Re: [TANKS] Remote Triggering - R/C MOSFET switch works fine
On Thursday, October 9, 2014 9:23:34 AM UTC-4, Frank Pittelli wrote: Agreed. I would never drive an inductive load directly with an opto-isolator. Fortunately, there are plenty of cheap FETs with built-in protection now that can be used. I disagree. I always use an opto-isolator between a microprocessor that reads RC servo signals and an inductive load. The opto-isolator protects the microprocessor from nasty inductive spikes. 1) small inductive loads (150 mA steady-state current) Drive the LED side of the opto-isolator with the microprocessor. The Darlington side can safely drive a small inductive load directly. 2) medium inductive load (2 A steady-state current) Drive the LED side of the opto-isolator with the microprocessor. Use the Darlington side to drive a BJT or MOSFET for the load. 3) large inductive loads (40 A steady-state current) Drive the LED side of a solid-state relay (SSR = big ass opto-isolator) with the microprocessor. The SSR output is a very large MOSFET with heat sinks that can drive the load. Driving an FET directly from the microprocessor does not protect it from large inductive spikes because there must be a common connection between the microprocessor GND, the FET source pin and low-side power for the load. Joe -- -- 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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [TANKS] Remote Triggering - R/C MOSFET switch works fine
Opto-isolators are slow to switch on and off. Darlington pairs are slow to switch on, and even slower to switch off. This results in a system thats slow to switch off, so by extension right as the inductor is kicking a huge current spike down to it, the opto-isolator is least equipped to handle it, being somewhere in the active region with high resistance. This also makes them unsuitable for driving the gate of a mosfet by the way, which is a capacitive load. In cases 2 and 3, you just drive an N mosfet directly. Heck, in all cases you just drive an NFET. I dont understand why anyone uses an SSR these days, when 200 amp mosfets can be had for 3$ each. Mosfets are cheaper, faster, and can handle more current safely. For your circuit to work, there must be a common ground. Ultimately the ground on your micro-controller and your load meet up no matter what you do. If you use an N mosfet, then the mosfet is on the low side of the load. I dont understand your reasoning for why you dont just drive the load off a mosfet. On Fri, Oct 10, 2014 at 7:44 AM, Joe Sommer anvil...@comcast.net wrote: On Thursday, October 9, 2014 9:23:34 AM UTC-4, Frank Pittelli wrote: Agreed. I would never drive an inductive load directly with an opto-isolator. Fortunately, there are plenty of cheap FETs with built-in protection now that can be used. I disagree. I always use an opto-isolator between a microprocessor that reads RC servo signals and an inductive load. The opto-isolator protects the microprocessor from nasty inductive spikes. 1) small inductive loads (150 mA steady-state current) Drive the LED side of the opto-isolator with the microprocessor. The Darlington side can safely drive a small inductive load directly. 2) medium inductive load (2 A steady-state current) Drive the LED side of the opto-isolator with the microprocessor. Use the Darlington side to drive a BJT or MOSFET for the load. 3) large inductive loads (40 A steady-state current) Drive the LED side of a solid-state relay (SSR = big ass opto-isolator) with the microprocessor. The SSR output is a very large MOSFET with heat sinks that can drive the load. Driving an FET directly from the microprocessor does not protect it from large inductive spikes because there must be a common connection between the microprocessor GND, the FET source pin and low-side power for the load. Joe -- -- 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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- Isaac Goldman 5142334423 This message contains confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e-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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [TANKS] Remote Triggering - R/C MOSFET switch works fine
What one of you E Guru's need to come up with is an R/C triggered circuit that can directly fire the solenoid in a typical e-marker. This bypasses the marker trigger board altogether. Loic's first combat tank had such a circuit but it had the nasty habit of firing when power was turned off. It was some sort of capacitor discharge circuit. -- -- 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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
RE: [TANKS] Remote Triggering - R/C MOSFET switch works fine
And this will be resolved when we have the “Hero” controller which will replace a LOT of features, like the pico switches, Marker onboard circuits, and 9V feeds to the Marker, Laser. In addition, it will be run by a PS2 controller which brings lots more capabilities, buttons and triggers. ‘Cross the Road Electronics’ is at the forefront of the Robotic world, but they are now very busy with some production schedule. They will work again on the Hero by late 2014. Cheers from Utah… can’t wait to cross aim with you guys in a couple of weeks! Loic -- -- 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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. attachment: Loic Anthian.vcf
Re: [TANKS] Remote Triggering - R/C MOSFET switch works fine
I tested the solution described below (4.2) today and it didn't work as expected ... but I believe it's a viable solution. Whaaa Stay tuned. I built a Pololu R/C Switch with Digital Output. The process was almost identical to the previous one for the Pololu MOSFET switch, except I needed two 2-position screw terminals as the two connections I needed were not adjacent. On the upside if I ever want to know the GOOD state and/or tap into the VCC it's ready to go. I turned on the marker power and my remote controller. When I turned on the power to the receiver (which also powers the switch board) the marker immediately fired. The switch board blinked its LED briefly about once a second as specified. I pressed the FIRE button on my controller and the switch board LED stayed on as specified while the button was pressed but the marker didn't fire. I pressed the manual trigger on the marker and it fired once, but didn't fire one subsequent presses. I pressed the FIRE button on my controller a few times and nothing. I pressed the manual trigger and again it fired once but no more. After scratching my head I realized the problem and a potential solution. Challenge: Explain the problem. Hint: All you need to know is in this discussion thread over the last few days. Advanced challenge #1: Devise a diagnostic procedure using the existing setup to confirm your theory. Advanced challenge #2: Propose a solution using the existing hardware. Principals of Tri-Pact are not eligible to enter. On Wednesday, October 8, 2014 5:48:33 PM UTC-4, Mike Lyons wrote: ... 4.1 Connect the output of a logic-level device (examples in 4 above) to the high side of the trigger, and the ground of the device to the marker ground (the low side of the trigger would be convenient). ... -- -- 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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [TANKS] Remote Triggering - R/C digital switch works fine ... I think!
I tested the solution described below (4.2) today and it didn't work as expected ... but I believe it's a viable solution. Whaaa Stay tuned. I built a Pololu R/C Switch with Digital Output. The process was almost identical to the previous one for the Pololu MOSFET switch, except I needed two 2-position screw terminals as the two connections I needed were not adjacent. On the upside if I ever want to know the GOOD state and/or tap into the VCC it's ready to go. I turned on the marker power and my remote controller. When I turned on the power to the receiver (which also powers the switch board) the marker immediately fired. The switch board blinked its LED briefly about once a second as specified. I pressed the FIRE button on my controller and the switch board LED stayed on as specified while the button was pressed but the marker didn't fire. I pressed the manual trigger on the marker and it fired once, but didn't fire one subsequent presses. I pressed the FIRE button on my controller a few times and nothing. I pressed the manual trigger and again it fired once but no more. After scratching my head I realized the problem and a potential solution. Challenge: Explain the problem. Hint: All you need to know is in this discussion thread over the last few days. Advanced challenge #1: Devise a diagnostic procedure using the existing setup to confirm your theory. Advanced challenge #2: Propose a solution using the existing hardware. Principals of Tri-Pact are not eligible to enter. On Wednesday, October 8, 2014 5:48:33 PM UTC-4, Mike Lyons wrote: ... 4.1 Connect the output of a logic-level device (examples in 4 above) to the high side of the trigger, and the ground of the device to the marker ground (the low side of the trigger would be convenient). ... -- -- 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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [TANKS] Remote Triggering - R/C MOSFET switch works fine
Not only has it already been built, but that circuit was battle-tested in the SU100, Patton and Semovente during the last battle. The board connects to the R/C receiver and directly drives the marker solenoid, as I explained in previous posts, exactly like an e-trigger. It even has a feature that allows you to restrict your firing rate to one shot every N seconds. I added that feature so that we can conduct the Doug Experiment one battle to see how reduced firing rates affect the game. On 10/10/2014 10:50 AM, TyngTech wrote: What one of you E Guru's need to come up with is an R/C triggered circuit that can directly fire the solenoid in a typical e-marker. This bypasses the marker trigger board altogether. Loic's first combat tank had such a circuit but it had the nasty habit of firing when power was turned off. It was some sort of capacitor discharge circuit. -- -- 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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [TANKS] Remote Triggering - R/C digital switch works fine ... I think!
oops ... the above should read I tested the solution described below (4.1) not (4.2). -- -- 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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [TANKS] Remote Triggering - R/C MOSFET switch works fine
On Friday, October 10, 2014 8:21:21 AM UTC-4, True North Armouries wrote: I dont understand why anyone uses an SSR these days, when 200 amp mosfets can be had for 3$ each. Build some high current drivers. Be certain to mount hefty heat sinks. Report back after you have fried a few. For your circuit to work, there must be a common ground. Ultimately the ground on your micro-controller and your load meet up no matter what you do. Incorrect - the GND on your microprocessor and the low-side power for your load are NOT connected when you use an opto-isolator or SSR. -- -- 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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [TANKS] Remote Triggering - R/C MOSFET switch works fine
The ground on the MCU and the low side dont connect to the same place through what black magic? Or are you lugging a second battery around? That sounds like a waste of space, and an additional thing to fail or malfunction at the wrong moment. I have built high current drivers, and I have yet to blow one or see one blow from an over-current. The one im designing for my tank even has closed loop current monitoring for additional protection. Actually come to think of it, SSRs are so inefficient and slow compared to mosfets I suspect for any power level you could affordably use an SSR, you would need very little heat sinking if any. On Fri, Oct 10, 2014 at 2:00 PM, Joe Sommer anvil...@comcast.net wrote: On Friday, October 10, 2014 8:21:21 AM UTC-4, True North Armouries wrote: I dont understand why anyone uses an SSR these days, when 200 amp mosfets can be had for 3$ each. Build some high current drivers. Be certain to mount hefty heat sinks. Report back after you have fried a few. For your circuit to work, there must be a common ground. Ultimately the ground on your micro-controller and your load meet up no matter what you do. Incorrect - the GND on your microprocessor and the low-side power for your load are NOT connected when you use an opto-isolator or SSR. -- -- 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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- Isaac Goldman 5142334423 This message contains confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e-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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [TANKS] Remote Triggering - R/C MOSFET switch works fine
The logic device has a small battery of its own, or is using the R/C receiver's battery. 4 x AAs work for me. The motor switched by the SSR (or whatever) has its own big fat battery. 12 V SLA or similar looks good. The two sides are isolated by the SSR (or whatever). On Friday, October 10, 2014 4:15:19 PM UTC-4, True North Armouries wrote: The ground on the MCU and the low side dont connect to the same place through what black magic? Or are you lugging a second battery around? That sounds like a waste of space, and an additional thing to fail or malfunction at the wrong moment. ... -- -- 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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[TANKS] 25 Pounder Upgrades for the Next Battle
Over the last month or so I've upgraded, rebuilt, and strengthened several parts of the Quarter Pounder. I thought it advisable to disclose the changes to the possible enemy to reduce the possibility of having too much of an advantage over them. Upgrade one: New barrel I during the last battle, I found the stock barrel to be accurate at close range, but longer range shots seemed to be sporadic. So after doing some homework I decided that a 32 Degrees Night Stick was a good choice. So far, no testing has taken place, but everywhere I read their accuracy is said to be up there with much higher end barrels. Upgrade two: New Actuator Not exactly an upgrade, more like a forced upgrade. The old actuator got fried, so I needed a replacement. Rebuild one: Elevate During the Quarter Pounder's quick build, I found that building the arms and lever for the elevate out of wood was the easiest choice. I was told that this setup should be replaced with either plastic or metal as the wood wouldn't hold up. Just recently I rebuilt everything with metal. Works very well and is plenty strong. https://lh4.googleusercontent.com/-lzXTxaDrllU/VDhq81pUi7I/AUc/W7piOlJJqYA/s1600/IMG_7937.JPG Strengthen one: Rotate When originally built, the cog wheel used a carriage bolt to attach the wheel to a coupler which is attached to the motor. The square neck of the carriage bolt was started to rotate its way loose. To fix this, I took a large washer and filed a square hole in it for the bolt. I then drilled to hole on either side of the waster and bolted this to the cog wheel. Much better and should last a long time. https://lh6.googleusercontent.com/-XASsNDYPwnk/VDhtQOCl_QI/AUo/neurFYVCKNM/s1600/IMG_7963.JPG Enjoy, C -- -- 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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [TANKS] 25 Pounder Upgrades for the Next Battle
The door lock actuator probably failed because it was powered too long. It consists of a simple motor that moves in one direction to move the control arm. When it reaches the far end, in a fraction of a second, the motor simply stalls and keeps pulling current until the voltage is turned off. If it pulls current for too long, it will heat up enough to break the small motor winding wire. Ask John all about it. He was the first person in the hobby to fry one ☺ When using a manual fire button, the button stays pressed for a lot longer than is required. So, you should always just tap the button, not press and hold. After the battle, I'll build a circuit for you that activates the actuator for 100 milliseconds, regardless of how long the button is pressed. We've been using that approach with door lock actuators ever since John blazed the trail and we haven't lost one since. -- -- 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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [TANKS] 25 Pounder Upgrades for the Next Battle
Ok, that makes sense. I believe the actuator failed when I put the cannon in storage. Sometimes, the servo doesn't quite inactivate the microswitch and I must not have caught it that time. I now know not to leave the battery hooked up not only to save the actuator, but also to help prolong the life of the LiPo. After the battle will be too late, Frank Just Kidding! :) I'm very interested and looking forward to getting one. :-) On Friday, October 10, 2014 8:13:01 PM UTC-4, Frank Pittelli wrote: The door lock actuator probably failed because it was powered too long. It consists of a simple motor that moves in one direction to move the control arm. When it reaches the far end, in a fraction of a second, the motor simply stalls and keeps pulling current until the voltage is turned off. If it pulls current for too long, it will heat up enough to break the small motor winding wire. Ask John all about it. He was the first person in the hobby to fry one ☺ When using a manual fire button, the button stays pressed for a lot longer than is required. So, you should always just tap the button, not press and hold. After the battle, I'll build a circuit for you that activates the actuator for 100 milliseconds, regardless of how long the button is pressed. We've been using that approach with door lock actuators ever since John blazed the trail and we haven't lost one since. -- -- 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 --- You received this message because you are subscribed to the Google Groups R/C Tank Combat group. To unsubscribe from this group and stop receiving emails from it, send an email to rctankcombat+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
