[TANKS] Re: High Power Servo Hack
On Jun 10, 3:04 pm, HV wrote: > My Hitec servos show 20 millisec pulse repetition period. ... <<< At the motor output? The conventional control signal is a 1-2 ms pulse every 20 ms. It would be simple to convert the control pulse to an output pulse at the same rate, i.e. one output pulse per input pulse. What I'm looking for is the duty cycle (the ratio of pulse "on" time to period) of the output pulse across the motor terminals (or even better between ground and the base of one of the output power transistors). At full speed, it should be 100% or close to it. --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
My Hitec servos show 20 millisec pulse repetition period. On Jun 9, 5:17 pm, "Doug Conn" wrote: > >> If anyone has access to a scope and can measure the duty cycle for any > > analog servo, I'd > appreciate a report. > > Fromhttp://www.societyofrobots.com/actuators_servos.shtml > > The motor of an analog servo receives a signal from the amplifier 30 times a > second or at 30Hz. This signal allows the amplifier to update the motor > position. Digital servos use a high frequency amplifier that updates the > servo motor position 300 times a second or at 300Hz. By updating the motor > position more often, the digital servo can deliver full torque from the > beginning of movement and increases the holding power of the servo. The > quick refresh also allows the digital servo to have a tighter deadband. > > - Doug --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
>> If anyone has access to a scope and can measure the duty cycle for any analog servo, I'd appreciate a report. >From http://www.societyofrobots.com/actuators_servos.shtml The motor of an analog servo receives a signal from the amplifier 30 times a second or at 30Hz. This signal allows the amplifier to update the motor position. Digital servos use a high frequency amplifier that updates the servo motor position 300 times a second or at 300Hz. By updating the motor position more often, the digital servo can deliver full torque from the beginning of movement and increases the holding power of the servo. The quick refresh also allows the digital servo to have a tighter deadband. - Doug --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Good news to report: My very slow but very high-torque servo is now working nicely. WARNING: ;~} High technology information follows. There are no relays, microswitches, baling wire, or tobacco spit used. If this offends you, stop reading. ;~} I took a cheap analog servo and removed the motor and all surface- mount devices connected to the motor terminal pads. I connected the pad to the inputs of a TLE 5206-2 H-bridge (as recommended elsewhere by Steve Tyng - thanks Steve!!!). I connected the ground of the servo board to the ground of the bridge. The H-bridge is supplied by a 12 volt SLA battery. The H-bridge output drives a gearmotor, the shaft of which drives a 5K pot via plastic gears. I'll take photos and post them when I build the next one. The gearmotor arm now moves steadily, slows down as it approaches the target location, then stops. No overshoot, no hunting, no humming. (No guarantee this will be true with a faster motor.) I suspect the problem with the previous approach was NOT the momentum of the geartrain but rather the slow turn-on and turn-off of the SSRs. The new H-bridge chip turns on and off in a few us (worst case 30). I'm very pleased with the result so far. Two minor issues: the travel is about 135 degrees (vs 80 for the original servo) and the motor is not running at full speed under servo control. The travel is no doubt due to different electrical rotation angles between the original pot and my replacement pot (which is much easier to mount reliably). I will check this later and report. I can fix it with a different pot, different gear ratios between the motor shaft and pot shaft, or use a "servo stretcher" to adjust the endpoints. I wasn't expecting the speed reduction. I suspect the servo duty cycle is significantly less than 100% at full speed. (It's possible this is a design "feature", to avoid possible shoot-through when suddenly changing directions at full speed.) If anyone has access to a scope and can measure the duty cycle for any analog servo, I'd appreciate a report. One caution: I zapped an H-bridge chip by not paying attention to the specs. The supply voltage can be up to 40V, but the logic input cannot exceed 7V. This means you can't pull these inputs up to the H- bridge supply (e.g. if you had an NPN open-collector output). The output from the servo board is a little under 6V or a little above zero, which works just fine. On May 16, 1:10 pm, Mike Lyons wrote: > I've just completed a prototype of a custom servo with massive torque > - the gearmotor has a reduction ratio of 1636 (and RPM of 1.5). ... --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Correction: I removed all the 2-terminal SMDs (from memory there were three, presumably capacitors to reduce noise). I did not remove the two PNP transistors that form the top legs of the H-bridge. On Jun 9, 4:08 pm, Mike Lyons wrote: ... > I took a cheap analog servo and removed the motor and all surface- > mount devices connected to the motor terminal pads. ... --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
I've just completed a prototype of a custom servo with massive torque
- the gearmotor has a reduction ratio of 1636 (and RPM of 1.5).
The control electronics are the guts of a standard R/C servo driving a
pair of SSRs in a half-bridge configuration ("push-pull") with a
bipolar power supply (+12/-12 V). I had these SSRs lying around,
otherwise I would have used an H-bridge chip as Steve Tyng recommended
elsewhere.
It consistently overshoots twice and then settles nicely (e.g. from
far left, it overshoots a little to the right, then overshoots a
little less to the left, then stops in the center).
I believe there are 2 problems:
1. The momentum of the gear train makes it take longer to slow down
(and start up) than the servo electronics design anticipated. The
damping factor needs to be a little higher so it slows down earlier as
it approaches the required position. I don't have documentation on
the servo controller chip so I don't know how feasible it would be to
change this. I started with the original pot from the servo, then
used a standard pot that is much easier to mount, and the results were
the same.
2. The SSRs have a maximum turn-off time of 1 ms, while the
transistors in the servo are probably under 1 us. The SSR maximum
turn-on time is 100 us, vs under 1 us again. The duty cycle delivered
to my gearmotor may be a lot wider than intended as it approaches the
required position, making the first problem worse. Joe Sommer tested
a couple of my SSRs and found one worked OK with his SSR controller
and one did not, apparently because they were right on the margin and
one was a little slower. In the next few weeks I plan to experiment
with different PWM parameters using a custom controller, and using an
H-bridge chip instead of the SSRs.
3. [Probably trivial] I'm using the existing transistors to drive the
SSRs. This might be compounding the second problem a little, but I
don't think enough to warrant breaking out the PWM signals before the
transistors. If someone can advise me otherwise I'll refine the
design.
I had considered using the guts of a digital servo, but
a) $$$ ($25 vs $9) and
b) the much higher PWM rate could lead to a "shoot-through" condition
where one SSR hasn't finished turning off when the other is turned on,
leading to magic smoke.
On Mar 26, 10:32 am, Frank Pittelli wrote:
...
> ... The motor
> momentum caused it to overshoot the mark, at which point the controller
> tries to reverse direction. But, if there's a little sloppiness in the
> pot, then it overshoots in the other direction or just hums while it
> stays in the same place.
...
--~--~-~--~~~---~--~~
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[TANKS] Re: High Power Servo Hack
I tried using the Oatley kits for the second revision RocketMan's steering. I also noticed the overshoot that Frank mentioned below. The main problem I had with them was that the position would start to 'drift' after a few minutes of operation. The device would drive the motor fully left or right and wouldn't go the other direction. Worse, it would keep the drive current on. I smoked several sets of driver FETs and burned up two Oatley circuit boards before I stopped trying. I was on the upper end of the specified load range (2 amps I think). I suspected maybe the heat was causing the driver FETs to leak and that's what was causing the drift. I added heat sinks and a small fan, but it didn't seem to make a difference. For steering, RocketMan ended up with a ServoCity servo gear box, a beefy servo, and a home-made mongo servo saver. I thought the steering was acceptable, but a little slow. We'll see how Tom feels about it :) My mechanical steering linkages and front suspension were probably the biggest steering impediments after I changed to the gearbox. - Doug -Original Message- From: rctankcombat@googlegroups.com [mailto:rctankcom...@googlegroups.com] On Behalf Of Frank Pittelli Sent: Thursday, March 26, 2009 10:32 AM To: rctankcombat@googlegroups.com Subject: [TANKS] Re: High Power Servo Hack Steve Tyng wrote: > The Oatley board does exactly what we have been discussing. I don't > have any direct experience with the kit but I know Frank built a > couple and had issues with them. Maybe he might elaborate. The only issues that I had during my testing was that the controller is "twitchy" if you have a sloppy pot and/or the motor speed is not adjusted properly. That is, it doesn't seem to account properly for the momentum of the motor and load when moving to a new position. The motor momentum caused it to overshoot the mark, at which point the controller tries to reverse direction. But, if there's a little sloppiness in the pot, then it overshoots in the other direction or just hums while it stays in the same place. So, the lesson is: use a high-quality pot when trying to build a heavy-duty servo. If possible, use an accurate multi-turn pot and gear it accordingly to the drive shaft. Doug, on the other hand, had lots more issues with them when he tested them ... primarily related to working load, if I recall, but he can elaborate better. Frank P. PS. It took quite a few weeks to get the Oatley boards from down-under because he sent them via regular snail-mail. --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Steve Tyng wrote: > The Oatley board does exactly what we have been discussing. I don't > have any direct experience with the kit but I know Frank built a > couple and had issues with them. Maybe he might elaborate. The only issues that I had during my testing was that the controller is "twitchy" if you have a sloppy pot and/or the motor speed is not adjusted properly. That is, it doesn't seem to account properly for the momentum of the motor and load when moving to a new position. The motor momentum caused it to overshoot the mark, at which point the controller tries to reverse direction. But, if there's a little sloppiness in the pot, then it overshoots in the other direction or just hums while it stays in the same place. So, the lesson is: use a high-quality pot when trying to build a heavy-duty servo. If possible, use an accurate multi-turn pot and gear it accordingly to the drive shaft. Doug, on the other hand, had lots more issues with them when he tested them ... primarily related to working load, if I recall, but he can elaborate better. Frank P. PS. It took quite a few weeks to get the Oatley boards from down-under because he sent them via regular snail-mail. --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Marc, The Oatley board does exactly what we have been discussing. I don't have any direct experience with the kit but I know Frank built a couple and had issues with them. Maybe he might elaborate. Steve --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
I considered and discarded the original idea I had for the BT-7's steering. I have a rather well made ball screw that I had intended to use for this purpose. The ball screw, from the motor end, would seem to work well. Friction is VERY low, good for not overworking the motor. The problem shows up when something hits the front wheels. There is a significant mechanical advantage (at least in the BT-7) from the wheel end. This means that if your motor is trying to go one way and your front wheels hit a rock, driving your wheels the other way, you are going to blow a fuse. An Acme screw might fare better, don't know how much. I think the better option would be a worm screw setup like a wiper or window or sunroof motor. In this setup, the gear can not work upon the worm, thus effecting a sort of stop. Of course, if a large enough force is applied to the gear, it will destroy the drive. Paul H. - Original Message - From: Derek Engelhaupt To: rctankcombat@googlegroups.com Sent: Wednesday, March 25, 2009 10:48 AM Subject: [TANKS] Re: High Power Servo Hack Has anyone considered using something like a lead screw connected to a motor for steering instead? I just bought one of these to do my traverse in the Sturmtiger. I bought an extra one to play with. I would think that it would work well for steering and be very robust as it's already welded to an aluminum plate. Derek T065 On Tue, Mar 24, 2009 at 11:38 PM, Paul Hilton wrote: Now that, Steve is good intel! I am VERY interested in the TLE 5206-2 driver. I am ready for the "Paul Harvey", (the rest of the story) whenever you would like to post it. A simple (very simple) diagram showing what to connect where and perhaps a socket part number would be useful. I have a whopping $8 burning a hole in my pocket! Paul H. - Original Message - From: "Steve Tyng" To: "R/C Tank Combat" Sent: Tuesday, March 24, 2009 4:47 PM Subject: [TANKS] High Power Servo Hack > > I've renamed the subject of this thread back to "High Power Servo > Hack" so lets not try to hijack it again (do not change the subject on > these emails). > > > Now back to the topic at hand. > > There's been discussion on making custom h-bridges in lieu of the > commercial boards available. I've found the following integrated h- > bridge modules currently listed on eBay. > > > http://cgi.ebay.com/MPM3002-Motorola-H-BRIDGE-MOSFET-POWER-MODULE_W0QQitemZ200308339465QQcmdZViewItemQQptZLH_DefaultDomain_0?_trksid=p3286.m20.l1116 > > http://cgi.ebay.com/1ea-ST-L6203-6203-Full-H-Bridge-Motor-DRIVER-IC_W0QQitemZ400020364797QQcmdZViewItemQQptZLH_DefaultDomain_0?_trksid=p3286.m20.l1116 > > These are obsolescent out-of-production h-bridge modules (include all > four driver FETS) that could be utilized (with a small amount of > additional components) to drive external motors (up to the current > rating of the module) and can be driven by the hacked servo. > > An interesting and current (in production) h-bridge device is the > Infineon TLE5206-2 driver. This is a basic h-bridge driver that > includes over amperage and temp sensing built-in and only requires one > external capacitor. It can handle a continuous 5amps which should be > plenty for a steering servo setup. DigiKey has these at under $8US in > single quantities. > > > http://www.infineon.com/dgdl/tle5206-2_20010619.pdf?folderId=db3a304412b407950112b43820d56a4a&fileId=db3a304412b407950112b438215b6a4b > > If you review the datasheets for these devices you will find all the > info needed to utilize them in the hacked servo project under > discussion. > > > Steve Tyng > > > > > > > > > > --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
I'm sure that would depend on a few different factors. First one would be the speed of the motor turning the screw. The second would be the travel time of the screw which would be determined by the thread count on the screw. Derek On Wed, Mar 25, 2009 at 11:01 AM, Thomas Lum wrote: > Would response time be a problem for this method? > > On Mar 25, 2009, at 10:48 AM, Derek Engelhaupt wrote: > > Has anyone considered using something like a lead screw connected to a > motor for steering instead? I just bought one of these to do my traverse in > the Sturmtiger. I bought an extra one to play with. I would think that it > would work well for steering and be very robust as it's already welded to an > aluminum plate. > > Derek > T065 > > On Tue, Mar 24, 2009 at 11:38 PM, Paul Hilton wrote: > >> >> Now that, Steve is good intel! I am VERY interested in the TLE 5206-2 >> driver. I am ready for the "Paul Harvey", (the rest of the story) >> whenever >> you would like to post it. A simple (very simple) diagram showing what to >> connect where and perhaps a socket part number would be useful. I have a >> whopping $8 burning a hole in my pocket! >> >> Paul H. >> - Original Message - >> From: "Steve Tyng" >> To: "R/C Tank Combat" >> Sent: Tuesday, March 24, 2009 4:47 PM >> Subject: [TANKS] High Power Servo Hack >> >> >> > >> > I've renamed the subject of this thread back to "High Power Servo >> > Hack" so lets not try to hijack it again (do not change the subject on >> > these emails). >> > >> > >> > Now back to the topic at hand. >> > >> > There's been discussion on making custom h-bridges in lieu of the >> > commercial boards available. I've found the following integrated h- >> > bridge modules currently listed on eBay. >> > >> > >> > >> http://cgi.ebay.com/MPM3002-Motorola-H-BRIDGE-MOSFET-POWER-MODULE_W0QQitemZ200308339465QQcmdZViewItemQQptZLH_DefaultDomain_0?_trksid=p3286.m20.l1116 >> > >> > >> http://cgi.ebay.com/1ea-ST-L6203-6203-Full-H-Bridge-Motor-DRIVER-IC_W0QQitemZ400020364797QQcmdZViewItemQQptZLH_DefaultDomain_0?_trksid=p3286.m20.l1116 >> > >> > These are obsolescent out-of-production h-bridge modules (include all >> > four driver FETS) that could be utilized (with a small amount of >> > additional components) to drive external motors (up to the current >> > rating of the module) and can be driven by the hacked servo. >> > >> > An interesting and current (in production) h-bridge device is the >> > Infineon TLE5206-2 driver. This is a basic h-bridge driver that >> > includes over amperage and temp sensing built-in and only requires one >> > external capacitor. It can handle a continuous 5amps which should be >> > plenty for a steering servo setup. DigiKey has these at under $8US in >> > single quantities. >> > >> > >> > >> http://www.infineon.com/dgdl/tle5206-2_20010619.pdf?folderId=db3a304412b407950112b43820d56a4a&fileId=db3a304412b407950112b438215b6a4b >> > >> > If you review the datasheets for these devices you will find all the >> > info needed to utilize them in the hacked servo project under >> > discussion. >> > >> > >> > Steve Tyng >> > >> > >> > >> > >> > >> > >> > >> > > >> > >> >> >> >> >> > > > > > > > > --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Steve, thanks for all the info. Two years ago we discussed the (discontinued) http://secure.oatleyelectronics.com/product_info.php?cPath=26_57&products_id=204&osCsid=124c5fdeefb5d022e450ff8ef26acbcc Would this do the same as the setup you mentioned? I can't believe there wouldn't be a market for the Oatley board. Marc --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Thanks for all the info Steve. Two years ago we discussed the (discontinued) http://secure.oatleyelectronics.com/product_info.php?cPath=26_57&products_id=204&osCsid=124c5fdeefb5d022e450ff8ef26acbcc Would that give the same result? And has anyone by change found a replacement for this discontinued item? Marc --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Would response time be a problem for this method? On Mar 25, 2009, at 10:48 AM, Derek Engelhaupt wrote: > Has anyone considered using something like a lead screw connected to > a motor for steering instead? I just bought one of these to do my > traverse in the Sturmtiger. I bought an extra one to play with. I > would think that it would work well for steering and be very robust > as it's already welded to an aluminum plate. > > Derek > T065 > > On Tue, Mar 24, 2009 at 11:38 PM, Paul Hilton > wrote: > > Now that, Steve is good intel! I am VERY interested in the TLE 5206-2 > driver. I am ready for the "Paul Harvey", (the rest of the story) > whenever > you would like to post it. A simple (very simple) diagram showing > what to > connect where and perhaps a socket part number would be useful. I > have a > whopping $8 burning a hole in my pocket! > > Paul H. > - Original Message - > From: "Steve Tyng" > To: "R/C Tank Combat" > Sent: Tuesday, March 24, 2009 4:47 PM > Subject: [TANKS] High Power Servo Hack > > > > > > I've renamed the subject of this thread back to "High Power Servo > > Hack" so lets not try to hijack it again (do not change the > subject on > > these emails). > > > > > > Now back to the topic at hand. > > > > There's been discussion on making custom h-bridges in lieu of the > > commercial boards available. I've found the following integrated h- > > bridge modules currently listed on eBay. > > > > > > http://cgi.ebay.com/MPM3002-Motorola-H-BRIDGE-MOSFET-POWER-MODULE_W0QQitemZ200308339465QQcmdZViewItemQQptZLH_DefaultDomain_0?_trksid=p3286.m20.l1116 > > > > http://cgi.ebay.com/1ea-ST-L6203-6203-Full-H-Bridge-Motor-DRIVER-IC_W0QQitemZ400020364797QQcmdZViewItemQQptZLH_DefaultDomain_0?_trksid=p3286.m20.l1116 > > > > These are obsolescent out-of-production h-bridge modules (include > all > > four driver FETS) that could be utilized (with a small amount of > > additional components) to drive external motors (up to the current > > rating of the module) and can be driven by the hacked servo. > > > > An interesting and current (in production) h-bridge device is the > > Infineon TLE5206-2 driver. This is a basic h-bridge driver that > > includes over amperage and temp sensing built-in and only requires > one > > external capacitor. It can handle a continuous 5amps which should > be > > plenty for a steering servo setup. DigiKey has these at under > $8US in > > single quantities. > > > > > > http://www.infineon.com/dgdl/tle5206-2_20010619.pdf?folderId=db3a304412b407950112b43820d56a4a&fileId=db3a304412b407950112b438215b6a4b > > > > If you review the datasheets for these devices you will find all the > > info needed to utilize them in the hacked servo project under > > discussion. > > > > > > Steve Tyng > > > > > > > > > > > > > > > > > > > > > > > > > > > --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Has anyone considered using something like a lead screw connected to a motor for steering instead? I just bought one of these to do my traverse in the Sturmtiger. I bought an extra one to play with. I would think that it would work well for steering and be very robust as it's already welded to an aluminum plate. Derek T065 On Tue, Mar 24, 2009 at 11:38 PM, Paul Hilton wrote: > > Now that, Steve is good intel! I am VERY interested in the TLE 5206-2 > driver. I am ready for the "Paul Harvey", (the rest of the story) whenever > you would like to post it. A simple (very simple) diagram showing what to > connect where and perhaps a socket part number would be useful. I have a > whopping $8 burning a hole in my pocket! > > Paul H. > - Original Message - > From: "Steve Tyng" > To: "R/C Tank Combat" > Sent: Tuesday, March 24, 2009 4:47 PM > Subject: [TANKS] High Power Servo Hack > > > > > > I've renamed the subject of this thread back to "High Power Servo > > Hack" so lets not try to hijack it again (do not change the subject on > > these emails). > > > > > > Now back to the topic at hand. > > > > There's been discussion on making custom h-bridges in lieu of the > > commercial boards available. I've found the following integrated h- > > bridge modules currently listed on eBay. > > > > > > > http://cgi.ebay.com/MPM3002-Motorola-H-BRIDGE-MOSFET-POWER-MODULE_W0QQitemZ200308339465QQcmdZViewItemQQptZLH_DefaultDomain_0?_trksid=p3286.m20.l1116 > > > > > http://cgi.ebay.com/1ea-ST-L6203-6203-Full-H-Bridge-Motor-DRIVER-IC_W0QQitemZ400020364797QQcmdZViewItemQQptZLH_DefaultDomain_0?_trksid=p3286.m20.l1116 > > > > These are obsolescent out-of-production h-bridge modules (include all > > four driver FETS) that could be utilized (with a small amount of > > additional components) to drive external motors (up to the current > > rating of the module) and can be driven by the hacked servo. > > > > An interesting and current (in production) h-bridge device is the > > Infineon TLE5206-2 driver. This is a basic h-bridge driver that > > includes over amperage and temp sensing built-in and only requires one > > external capacitor. It can handle a continuous 5amps which should be > > plenty for a steering servo setup. DigiKey has these at under $8US in > > single quantities. > > > > > > > http://www.infineon.com/dgdl/tle5206-2_20010619.pdf?folderId=db3a304412b407950112b43820d56a4a&fileId=db3a304412b407950112b438215b6a4b > > > > If you review the datasheets for these devices you will find all the > > info needed to utilize them in the hacked servo project under > > discussion. > > > > > > Steve Tyng > > > > > > > > > > > > > > > > > > > > > > > > > --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Now that, Steve is good intel! I am VERY interested in the TLE 5206-2 driver. I am ready for the "Paul Harvey", (the rest of the story) whenever you would like to post it. A simple (very simple) diagram showing what to connect where and perhaps a socket part number would be useful. I have a whopping $8 burning a hole in my pocket! Paul H. - Original Message - From: "Steve Tyng" To: "R/C Tank Combat" Sent: Tuesday, March 24, 2009 4:47 PM Subject: [TANKS] High Power Servo Hack > > I've renamed the subject of this thread back to "High Power Servo > Hack" so lets not try to hijack it again (do not change the subject on > these emails). > > > Now back to the topic at hand. > > There's been discussion on making custom h-bridges in lieu of the > commercial boards available. I've found the following integrated h- > bridge modules currently listed on eBay. > > > http://cgi.ebay.com/MPM3002-Motorola-H-BRIDGE-MOSFET-POWER-MODULE_W0QQitemZ200308339465QQcmdZViewItemQQptZLH_DefaultDomain_0?_trksid=p3286.m20.l1116 > > http://cgi.ebay.com/1ea-ST-L6203-6203-Full-H-Bridge-Motor-DRIVER-IC_W0QQitemZ400020364797QQcmdZViewItemQQptZLH_DefaultDomain_0?_trksid=p3286.m20.l1116 > > These are obsolescent out-of-production h-bridge modules (include all > four driver FETS) that could be utilized (with a small amount of > additional components) to drive external motors (up to the current > rating of the module) and can be driven by the hacked servo. > > An interesting and current (in production) h-bridge device is the > Infineon TLE5206-2 driver. This is a basic h-bridge driver that > includes over amperage and temp sensing built-in and only requires one > external capacitor. It can handle a continuous 5amps which should be > plenty for a steering servo setup. DigiKey has these at under $8US in > single quantities. > > > http://www.infineon.com/dgdl/tle5206-2_20010619.pdf?folderId=db3a304412b407950112b43820d56a4a&fileId=db3a304412b407950112b438215b6a4b > > If you review the datasheets for these devices you will find all the > info needed to utilize them in the hacked servo project under > discussion. > > > Steve Tyng > > > > > > > > > > --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
I was researching better steering and found this youtube video on a similar idea of using a wiper motor to steer with servo feedback. http://www.youtube.com/watch?v=eimYnrCMOLI Tom --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Steve, The SSR option looks quite interesting. How would this be coupled with the hacked servo? I've only seen schematics for H-bridges, how do they interconnect? I may in fact go with the commercial H-bridge. At best I would save $20 building a MOSFET H-bridge, even less building one using SSRs. We'll see. --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Paul, Your schematic is a basic h-bridge and would work fine. One note is that it has parallel 19amp p-channel mosfets on the high side (to somewhat match the 50amp n-channel mosfets on the low side). You could remove the extra p-channel mosfets as long as you stay within the current ratings of the p-channel mosfets. About the current ratings of the components. At first glance it would seem these components are vastly overrated for the motors we want to drive. In fact they may be underrated. The stated current ratings for mosfets are usually the max rating for a period measured in milliseconds and the manufacturer is assuming that's with sufficient heat sinking installed. If you dig into the spec sheets of these componets you will find the "real world" current ratings are always much less than the advertised ratings. You will need to build the circuit to handle the stall current of the motor you will be using. On the voltage, the components you will use are marked with a maximum voltage. As long as you stay under your lowest rated component you should be fine. Mosfets are very sensitive to static and are easy to destroy just by handling them improperly during assembly so order extra. You can also assemble an h-bridge using dc solid state relays (SSR's) simulare to what Joe Summer did with his controler on his Hetzer. http://rctankcombat.com/articles/speed-control/084Hbridge.jpg SSR' are nice because they are designed to be abused. Instead of using the big Crydom SSR's you could use smaller pc mount SSR's like these: http://www.alltronics.com/cgi-bin/item/24B003/search/Grayhill-70M-ODC5-Relay The only issue with the SSR's is that they weren't really designed with high speed switching operations in mind so may not be able switch at the frequency that the hacked servo is switching at. We know the Crydom D1D40's will switch reliably to a certain frequency but that was proved by buying and testing them ourselves. If you want to try the Grayhill SSR's listed above you'll be blazing a new path for the hobby. I'm all about reliability in my combat vehicles. To me it isn't worth saving a few bucks on a critical component just to have it fail on one of the two weekends a year I really need it to work. So my preference if I were to build this hack would be the commercial h-bridge, an SSR h-bridge, and finally the homebuilt mosfet h-bridge. I'd also acquire/ build a second as a spare. Steve Tyng Concerning your voltage On Mar 4, 1:37 am, "Paul Hilton" wrote: > OK Steve, sometimes I'm a bit 'thick" when it comes to electronics. I have > zero experience with H-bridges and MOSFETs in general. Are you saying that > this will do the job? > > http://130.94.182.150/servo.jpg > > Seems vastly overpowered for my app, but I'll give it a go. I assume that > the ".2" beside the capacitor is .2 micro farads. I also wonder about > substitutions for the MOSFETs. If I used smaller MOSFETs, would it all > still work? What about 2 N-channel and 2 P-channel, rather than 2 and 4? > And what of voltage, is this not an issue? Seems kind of important to me. > And why build a 38 amp H-bridge, then call out "three good gearmotors for > steering servos" none of which draws more than 750 mA, like these guys have > done? Seems like a bit of overkill. > > Paul H. > > - Original Message - > From: "Steve Tyng" > To: "R/C Tank Combat" > Sent: Saturday, February 28, 2009 11:15 AM > Subject: [TANKS] Re: High Power Servo Hack > > > Paul, > > > The Pololu board would not work to "amplify" the current capability of > > a standard r/c servo. The Pololu board is a bit to intelligent in > > that it has it's own processing capability and determines motor speed > > and direction via separate PWM and direction signals. Though the > > Pololu board has an h-bridge the board itself is not controlled like a > > typical h-bridge circuit. It is meant to be controlled be a > > microprocessor and not as something as crude as a hacked hobby servo. > > > The hack we are discussing replaces the internal and very basic h- > > bridge circuit of the servo with an external higher capacity circuit. > > This h-bridge circuit requires a PWM speed signal on one of either two > > inputs unlike the Pololu board which has only one input for the PWM > > speed signal and a second to determine direction. > > > Simple h-bridge boards a few and far between. The Tecel was one, > > RobotPower simple h-bridge is the only other commercial h-bridge that > > I can recall offhand. Most servo hacks off this type I've read about > > usually involves making a custom h-bridge board, which act
[TANKS] Re: High Power Servo Hack
OK Steve, sometimes I'm a bit 'thick" when it comes to electronics. I have zero experience with H-bridges and MOSFETs in general. Are you saying that this will do the job? http://130.94.182.150/servo.jpg Seems vastly overpowered for my app, but I'll give it a go. I assume that the ".2" beside the capacitor is .2 micro farads. I also wonder about substitutions for the MOSFETs. If I used smaller MOSFETs, would it all still work? What about 2 N-channel and 2 P-channel, rather than 2 and 4? And what of voltage, is this not an issue? Seems kind of important to me. And why build a 38 amp H-bridge, then call out "three good gearmotors for steering servos" none of which draws more than 750 mA, like these guys have done? Seems like a bit of overkill. Paul H. - Original Message - From: "Steve Tyng" To: "R/C Tank Combat" Sent: Saturday, February 28, 2009 11:15 AM Subject: [TANKS] Re: High Power Servo Hack > > Paul, > > The Pololu board would not work to "amplify" the current capability of > a standard r/c servo. The Pololu board is a bit to intelligent in > that it has it's own processing capability and determines motor speed > and direction via separate PWM and direction signals. Though the > Pololu board has an h-bridge the board itself is not controlled like a > typical h-bridge circuit. It is meant to be controlled be a > microprocessor and not as something as crude as a hacked hobby servo. > > The hack we are discussing replaces the internal and very basic h- > bridge circuit of the servo with an external higher capacity circuit. > This h-bridge circuit requires a PWM speed signal on one of either two > inputs unlike the Pololu board which has only one input for the PWM > speed signal and a second to determine direction. > > Simple h-bridge boards a few and far between. The Tecel was one, > RobotPower simple h-bridge is the only other commercial h-bridge that > I can recall offhand. Most servo hacks off this type I've read about > usually involves making a custom h-bridge board, which actually isn't > very difficult to do. Here's a link for one such project. > > http://130.94.182.150/mowers.htm (scroll down to "CONVERTING STANDARD > R/C SERVOS INTO MONSTER SERVOS") > > > Steve Tyng > > > > > --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Paul, The Pololu board would not work to "amplify" the current capability of a standard r/c servo. The Pololu board is a bit to intelligent in that it has it's own processing capability and determines motor speed and direction via separate PWM and direction signals. Though the Pololu board has an h-bridge the board itself is not controlled like a typical h-bridge circuit. It is meant to be controlled be a microprocessor and not as something as crude as a hacked hobby servo. The hack we are discussing replaces the internal and very basic h- bridge circuit of the servo with an external higher capacity circuit. This h-bridge circuit requires a PWM speed signal on one of either two inputs unlike the Pololu board which has only one input for the PWM speed signal and a second to determine direction. Simple h-bridge boards a few and far between. The Tecel was one, RobotPower simple h-bridge is the only other commercial h-bridge that I can recall offhand. Most servo hacks off this type I've read about usually involves making a custom h-bridge board, which actually isn't very difficult to do. Here's a link for one such project. http://130.94.182.150/mowers.htm (scroll down to "CONVERTING STANDARD R/C SERVOS INTO MONSTER SERVOS") Steve Tyng --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Doug wrote: > I think that having a powerful steering servo is only part of the solution. > You also need a mechanism to handle the jolts and bumps without transmitting > the shock to the servo (or gearmotor). Agreed. A thought I've just had is that since the system we are discussing involves a position sensor separate from the gearmotor, there is no overriding reason to attach the sensor directly to the motor output. The sensor could be connected to the steering assembly directly instead. The gearmotor could then be attached to the steering via a slip clutch assembly. Any shocks to the steering would be absorbed in the slip clutch thus avoiding damage to the gearmotor. On the sensor mounting, one would need to ensure the travel of the steering assembly does not exceed the throw of the sensor which would damage it. Steve Tyng --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Thanks Steve, I have a pair of these: http://www.allelectronics.com/make-a-store/item/DCM-316/12VDC-SUNROOF-MOTOR/1.html that I may be able to adapt, the shafts are a bit on the short side but I may be able to stick a slotted arm on. If not, I'll look at the 24V Mabuchi gearmotor you have listed. I also wonder if there might be a cheaper alternative to the motor controller you mention. One might be: http://www.pololu.com/catalog/product/755 I'm sure that if I look hard enough, I could find others. Paul H. - Original Message - From: "Steve Tyng" To: "R/C Tank Combat" Sent: Friday, February 27, 2009 12:54 PM Subject: [TANKS] Re: High Power Servo Hack > > Paul, > > I have not personally tried this yet but I see no reason why it will > not work well. Some possible gearmotors for steering our armoured > cars could be: > > http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1634&catname=electric > http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1664&catname=electric > http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1257&catname=electric > http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1685&catname=electric > http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1693&catname=electric > > > PF, > > The Tecel board seams to be no longer available that's why I listed > the Robot-Power alternative. I've spoken with the owner of Robot > Power and he stated that his Simple H-Bridge is being used to make > high power servos by others. > > > Steve Tyng > > > > > > On Feb 27, 11:55 am, pixelFiend wrote: >> I've been wanting to do this as well for a project. Every time I look >> into >> it however, I keep running up against the Tecel website, which turns up >> an >> "access forbidden" message on the D200. I make a note to call or look >> into >> it further, then other things come up. >> I have several motors I could use for this— does anyone have any info on >> Tecel? Are they still a going concern, or have you bought from them? >> >> PF >> >> >> >> On Fri, Feb 27, 2009 at 11:38 AM, Paul Hilton wrote: >> >> > Steve, you must have been reading my mind. I was just thinking about a >> > solution for the BT-7's steering. Have you tried this? Seems like a >> > good >> > choice for large wheeled vehicles! >> >> > Paul H. >> > - Original Message - >> > From: "Steve Tyng" >> > To: "R/C Tank Combat" >> > Sent: Friday, February 27, 2009 10:03 AM >> > Subject: [TANKS] High Power Servo Hack >> >> > > Here's an interesting article on modifying a standard servo to drive >> > > an external gearmotor. Basically the geartrain is removed from the >> > > servo which is then used as a position sensor for the gearmotor. The >> > > servo electronics are used to drive an offboard h-bridge. >> >> > >http://www.fieroaddiction.com/servo.html >> >> > > An h-bridge that would work well with this setup (the Tecel D200 >> > > referenced doesn't appear to be available anymore). >> >> > >http://www.robotpower.com/products/simple-h_info.html >> >> > > Steve Tyng >> >> -- >> PF >> >> astromechbuilder.com >> astromechfactory.com > > > > --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
I think that having a powerful steering servo is only part of the solution. You also need a mechanism to handle the jolts and bumps without transmitting the shock to the servo (or gearmotor). I finally found something that worked pretty well for RocketMan. Check out this out RC Tank Combat post. http://www.rctankcombat.com/archive/2007-08/msg00415.html -Doug From: rctankcombat@googlegroups.com [mailto:rctankcom...@googlegroups.com] On Behalf Of Chrysanthos Kanellopoulos Sent: Friday, February 27, 2009 11:54 PM To: rctankcombat@googlegroups.com Subject: [TANKS] Re: High Power Servo Hack Lots of voltage but they are inexpensive. I don't know if they spin indefinitely or if they are "programmed" to rotate only 60 or 90 degrees left and right to suit a steer system, or what does the trick. Chrys Paul, I have not personally tried this yet but I see no reason why it will not work well. Some possible gearmotors for steering our armoured cars could be: http://surpluscenter.com/item.asp?UID=2009022709083981 <http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1634&catname= electric> &item=5-1634&catname=electric http://surpluscenter.com/item.asp?UID=2009022709083981 <http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1664&catname= electric> &item=5-1664&catname=electric http://surpluscenter.com/item.asp?UID=2009022709083981 <http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1257&catname= electric> &item=5-1257&catname=electric http://surpluscenter.com/item.asp?UID=2009022709083981 <http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1685&catname= electric> &item=5-1685&catname=electric http://surpluscenter.com/item.asp?UID=2009022709083981 <http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1693&catname= electric> &item=5-1693&catname=electric PF, The Tecel board seams to be no longer available that's why I listed the Robot-Power alternative. I've spoken with the owner of Robot Power and he stated that his Simple H-Bridge is being used to make high power servos by others. Steve Tyng On Feb 27, 11:55 am, pixelFiend wrote: > I've been wanting to do this as well for a project. Every time I look into > it however, I keep running up against the Tecel website, which turns up an > "access forbidden" message on the D200. I make a note to call or look into > it further, then other things come up. > I have several motors I could use for this- does anyone have any info on > Tecel? Are they still a going concern, or have you bought from them? > > PF > > > > On Fri, Feb 27, 2009 at 11:38 AM, Paul Hilton wrote: > > > Steve, you must have been reading my mind. I was just thinking about a > > solution for the BT-7's steering. Have you tried this? Seems like a good > > choice for large wheeled vehicles! > > > Paul H. > > - Original Message - > > From: "Steve Tyng" > > To: "R/C Tank Combat" > > Sent: Friday, February 27, 2009 10:03 AM > > Subject: [TANKS] High Power Servo Hack > > > > Here's an interesting article on modifying a standard servo to drive > > > an external gearmotor. Basically the geartrain is removed from the > > > servo which is then used as a position sensor for the gearmotor. The > > > servo electronics are used to drive an offboard h-bridge. > > > >http://www.fieroaddiction.com/servo.html > > > > An h-bridge that would work well with this setup (the Tecel D200 > > > referenced doesn't appear to be available anymore). > > > >http://www.robotpower.com/products/simple-h_info.html > > > > Steve Tyng > > -- > PF > > astromechbuilder.com > astromechfactory.com -- PF astromechbuilder.com astromechfactory.com http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Lots of voltage but they are inexpensive. I don't know if they spin indefinitely or if they are "programmed" to rotate only 60 or 90 degrees left and right to suit a steer system, or what does the trick. Chrys Paul, I have not personally tried this yet but I see no reason why it will not work well. Some possible gearmotors for steering our armoured cars could be: http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1634&catname=electric http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1664&catname=electric http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1257&catname=electric http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1685&catname=electric http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1693&catname=electric PF, The Tecel board seams to be no longer available that's why I listed the Robot-Power alternative. I've spoken with the owner of Robot Power and he stated that his Simple H-Bridge is being used to make high power servos by others. Steve Tyng On Feb 27, 11:55 am, pixelFiend wrote: > I've been wanting to do this as well for a project. Every time I look into > it however, I keep running up against the Tecel website, which turns up an > "access forbidden" message on the D200. I make a note to call or look into > it further, then other things come up. > I have several motors I could use for this— does anyone have any info on > Tecel? Are they still a going concern, or have you bought from them? > > PF > > > > On Fri, Feb 27, 2009 at 11:38 AM, Paul Hilton wrote: > > > Steve, you must have been reading my mind. I was just thinking about a > > solution for the BT-7's steering. Have you tried this? Seems like a good > > choice for large wheeled vehicles! > > > Paul H. > > - Original Message - > > From: "Steve Tyng" > > To: "R/C Tank Combat" > > Sent: Friday, February 27, 2009 10:03 AM > > Subject: [TANKS] High Power Servo Hack > > > > Here's an interesting article on modifying a standard servo to drive > > > an external gearmotor. Basically the geartrain is removed from the > > > servo which is then used as a position sensor for the gearmotor. The > > > servo electronics are used to drive an offboard h-bridge. > > > >http://www.fieroaddiction.com/servo.html > > > > An h-bridge that would work well with this setup (the Tecel D200 > > > referenced doesn't appear to be available anymore). > > > >http://www.robotpower.com/products/simple-h_info.html > > > > Steve Tyng > > -- > PF > > astromechbuilder.com > astromechfactory.com -- PF astromechbuilder.com astromechfactory.com --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Ah, thanks Steve. I'm sorry, I hadn't read through the bottom of your message. I'll check them out. PF On Fri, Feb 27, 2009 at 12:54 PM, Steve Tyng wrote: > > Paul, > > I have not personally tried this yet but I see no reason why it will > not work well. Some possible gearmotors for steering our armoured > cars could be: > > > http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1634&catname=electric > > http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1664&catname=electric > > http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1257&catname=electric > > http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1685&catname=electric > > http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1693&catname=electric > > > PF, > > The Tecel board seams to be no longer available that's why I listed > the Robot-Power alternative. I've spoken with the owner of Robot > Power and he stated that his Simple H-Bridge is being used to make > high power servos by others. > > > Steve Tyng > > > > > > On Feb 27, 11:55 am, pixelFiend wrote: > > I've been wanting to do this as well for a project. Every time I look > into > > it however, I keep running up against the Tecel website, which turns up > an > > "access forbidden" message on the D200. I make a note to call or look > into > > it further, then other things come up. > > I have several motors I could use for this— does anyone have any info on > > Tecel? Are they still a going concern, or have you bought from them? > > > > PF > > > > > > > > On Fri, Feb 27, 2009 at 11:38 AM, Paul Hilton > wrote: > > > > > Steve, you must have been reading my mind. I was just thinking about a > > > solution for the BT-7's steering. Have you tried this? Seems like a > good > > > choice for large wheeled vehicles! > > > > > Paul H. > > > - Original Message - > > > From: "Steve Tyng" > > > To: "R/C Tank Combat" > > > Sent: Friday, February 27, 2009 10:03 AM > > > Subject: [TANKS] High Power Servo Hack > > > > > > Here's an interesting article on modifying a standard servo to drive > > > > an external gearmotor. Basically the geartrain is removed from the > > > > servo which is then used as a position sensor for the gearmotor. The > > > > servo electronics are used to drive an offboard h-bridge. > > > > > >http://www.fieroaddiction.com/servo.html > > > > > > An h-bridge that would work well with this setup (the Tecel D200 > > > > referenced doesn't appear to be available anymore). > > > > > >http://www.robotpower.com/products/simple-h_info.html > > > > > > Steve Tyng > > > > -- > > PF > > > > astromechbuilder.com > > astromechfactory.com > > > -- PF astromechbuilder.com astromechfactory.com --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Paul, I have not personally tried this yet but I see no reason why it will not work well. Some possible gearmotors for steering our armoured cars could be: http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1634&catname=electric http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1664&catname=electric http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1257&catname=electric http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1685&catname=electric http://surpluscenter.com/item.asp?UID=2009022709083981&item=5-1693&catname=electric PF, The Tecel board seams to be no longer available that's why I listed the Robot-Power alternative. I've spoken with the owner of Robot Power and he stated that his Simple H-Bridge is being used to make high power servos by others. Steve Tyng On Feb 27, 11:55 am, pixelFiend wrote: > I've been wanting to do this as well for a project. Every time I look into > it however, I keep running up against the Tecel website, which turns up an > "access forbidden" message on the D200. I make a note to call or look into > it further, then other things come up. > I have several motors I could use for this— does anyone have any info on > Tecel? Are they still a going concern, or have you bought from them? > > PF > > > > On Fri, Feb 27, 2009 at 11:38 AM, Paul Hilton wrote: > > > Steve, you must have been reading my mind. I was just thinking about a > > solution for the BT-7's steering. Have you tried this? Seems like a good > > choice for large wheeled vehicles! > > > Paul H. > > - Original Message - > > From: "Steve Tyng" > > To: "R/C Tank Combat" > > Sent: Friday, February 27, 2009 10:03 AM > > Subject: [TANKS] High Power Servo Hack > > > > Here's an interesting article on modifying a standard servo to drive > > > an external gearmotor. Basically the geartrain is removed from the > > > servo which is then used as a position sensor for the gearmotor. The > > > servo electronics are used to drive an offboard h-bridge. > > > >http://www.fieroaddiction.com/servo.html > > > > An h-bridge that would work well with this setup (the Tecel D200 > > > referenced doesn't appear to be available anymore). > > > >http://www.robotpower.com/products/simple-h_info.html > > > > Steve Tyng > > -- > PF > > astromechbuilder.com > astromechfactory.com --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
I've been wanting to do this as well for a project. Every time I look into it however, I keep running up against the Tecel website, which turns up an "access forbidden" message on the D200. I make a note to call or look into it further, then other things come up. I have several motors I could use for this— does anyone have any info on Tecel? Are they still a going concern, or have you bought from them? PF On Fri, Feb 27, 2009 at 11:38 AM, Paul Hilton wrote: > > Steve, you must have been reading my mind. I was just thinking about a > solution for the BT-7's steering. Have you tried this? Seems like a good > choice for large wheeled vehicles! > > Paul H. > - Original Message - > From: "Steve Tyng" > To: "R/C Tank Combat" > Sent: Friday, February 27, 2009 10:03 AM > Subject: [TANKS] High Power Servo Hack > > > > > > Here's an interesting article on modifying a standard servo to drive > > an external gearmotor. Basically the geartrain is removed from the > > servo which is then used as a position sensor for the gearmotor. The > > servo electronics are used to drive an offboard h-bridge. > > > > http://www.fieroaddiction.com/servo.html > > > > An h-bridge that would work well with this setup (the Tecel D200 > > referenced doesn't appear to be available anymore). > > > > http://www.robotpower.com/products/simple-h_info.html > > > > > > Steve Tyng > > > > > > > > > > > > > > > -- PF astromechbuilder.com astromechfactory.com --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
[TANKS] Re: High Power Servo Hack
Steve, you must have been reading my mind. I was just thinking about a solution for the BT-7's steering. Have you tried this? Seems like a good choice for large wheeled vehicles! Paul H. - Original Message - From: "Steve Tyng" To: "R/C Tank Combat" Sent: Friday, February 27, 2009 10:03 AM Subject: [TANKS] High Power Servo Hack > > Here's an interesting article on modifying a standard servo to drive > an external gearmotor. Basically the geartrain is removed from the > servo which is then used as a position sensor for the gearmotor. The > servo electronics are used to drive an offboard h-bridge. > > http://www.fieroaddiction.com/servo.html > > An h-bridge that would work well with this setup (the Tecel D200 > referenced doesn't appear to be available anymore). > > http://www.robotpower.com/products/simple-h_info.html > > > Steve Tyng > > > > > --~--~-~--~~~---~--~~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~--~~~~--~~--~--~---
