OK - great!. For a direct email, is your address mtdsand...@gmail.com? Alan
On Mon, Jul 20, 2015 at 9:57 PM, Gerald Coley <ger...@beagleboard.org> wrote: > That is a long email. Send me a direct email, and at some point we can > have a discussion. > > Gerald > > > On Mon, Jul 20, 2015 at 6:36 PM, Alan Rosenbloom <rosenbloo...@gmail.com> > wrote: > >> Gerald: I am super impressed that you would offer your valuable time to >> help with not much in return than thanks. >> >> Background: I’m developing a complicated prototype and I am new to >> embedded systems. I was fairly frustrated that I could not “just hook >> things up” and have them at least not destroy the BBB while testing. I am >> beginning to understand that, like any device, more capability comes with >> more complexity and vulnerabilities. I still see the BBB as an amazing >> opportunity for inventors overall and realize that I need to learn more to >> use it properly. >> >> I cannot point to one circuit that caused the damage to >> the BBBs because I am trying different arrangements to integrate multiple >> devices. However, if you could answer some basic questions on design >> strategy, that could help. >> >> >> *Here’s what I need to accomplish:* >> >> I need to power 4 accessories: (1) a small stepper motor through the >> Pololu DRV8834 driver board. It consumes about 200 – 300 mA at 5 volts, (2) >> an IC chip via pulse wave modulation – it requires about 620mA at 1.55V, >> (3) a small DC motor which consumes about 40 mA at 3V (either by PWM and >> a relay or straight from a 3.3 V source) and (4) a small cooling fan – >> consumes about 120 mA at 5 V. >> >> I need to control turning all these on and off by a clock function. >> >> I need to read a GVS digital sensor: consumes less than 10 mA at 5 V. >> >> I need to read a GVS analog input: 5V input, output < 1 volt. >> >> I need to read DC voltages (analog): (1) on a pin on the DRV8834 driver >> board (0-1 volt range), (2) on a sensor with special input requirements – >> it needs both (+) 5 volts AND (-) 5 volts inputs to power it. The (-) >> voltage is derived from (+) 5 V using this inverter ICL7660A, which I have >> found to be about 91% efficient at converting DC (+) to DC(-) for this >> application. Sensor output max about 1.2 volts. >> >> Finally, I need to add and read a real time clock (RTC) such as the >> Chronodot (Adafruit) – requires I2C bus SDA, and SCL, as well as GND and >> (+) 5V. >> >> >> *What do you think of these strategies:* >> >> (1) Use the BBB-GVS board (http://beagleboard.org/project/BBB-GVS/). >> This board appears to provide a layer of protection from the sensor voltage >> inputs and power outputs for the BBB. The problem is they may not be a >> reliable supplier and I cannot tell if this board will accomplish all these >> tasks. >> >> (2) Use the BBB only for logic and supply all the power from an >> independent (probably 5V cell phone charger power pack) source with voltage >> regulator, using PWM and relays to regulate the voltages lower than 5 V and >> relays to control intermittent power needs. Would this be safer for the BBB >> i.e. not using power directly off the BBB while trying to read sensor >> output at the same time? It seems dangerous to me tying all the grounds >> together (analog, digital and power) that would be required to get both >> power out of the BBB and signal into it. >> >> (3) Power the BBB via a 3.7 volt backup battery through TP5 and TP8 >> to prevent abrupt cessation of power should a system failure occur. Seems >> like it would be possible to write code to give the “sudo shutdown –h now” >> command when the power went down. This would allow the PMIC time to do an >> orderly shutdown. >> >> >> >> I suspect that the sensors may be putting voltages on the BBB pins before >> they are powered up as part of the problem, but I am not sure how to >> prevent this. Is there a way to power up the sensors after the BBB has >> properly booted and to shut them down before the PMIC does its shutdown >> sequence? Any other external wiring or devices that could help safeguard >> the BBB? Any advice you can offer on any of this or other ways to protect >> the BBB would be appreciated. >> >> On Sat, Jul 18, 2015 at 8:31 PM, Gerald Coley <ger...@beagleboard.org> >> wrote: >> >>> If you do not use it properly, it will be damaged. That applies to every >>> electronic circuit ever designed. I would have stopped using the circuitry >>> after the second try. >>> >>> I would be happy to look at your circuit and see if I can identify what >>> the issue might be. >>> >>> Gerald >>> >>> >>> On Fri, Jul 17, 2015 at 10:27 PM, <rosenbloo...@gmail.com> wrote: >>> >>>> I now have 4 damaged or dead BBBs. On this last board (Element 14), I >>>> had only a stepper motor driver board connected (Pololu DRV8834), and >>>> nothing else. The DRV8834 was initially drawing power from the VDD5v on the >>>> BBB. The BBB "blacked out" twice while nothing was happening and while >>>> connected to both a 5V regulated power supply (Adafruit) and USB power. I >>>> was worried that the DRV8834 was drawing too much power (although I have >>>> found it uses < 200 mA @ 5V), so I used a separate power supply for the >>>> DRB8834. Only the logic of the DRV8834 was hooked up to the BBB - nothing >>>> that would supply power and no analog inputs. The third blackout also >>>> occurred without an obvious precipitant - again with both power sources >>>> connected (USB and barrel plug). Now the power LED flashes briefly when >>>> either USB or barrel plug power (Adafruit power source for BBB) is >>>> connected to the BBB. It will not sustain the power button nor boot up. >>>> >>>> This seems to be a repetitive theme on this forum. I am losing faith in >>>> the BBB ever functioning in a real world environment if it is this fragile. >>>> Is there any way to protect the BBB processor (or whatever is blowing) with >>>> external circuitry or power? >>>> >>>> Appreciate any help. I'm now out over $200 with these boards and I >>>> cannot identify anything that should be damaging them. Considering changing >>>> to another system at this point. Although I am impressed with the >>>> capability of the BBB, I would not call it a robust system. >>>> >>>> Help! >>>> >>>> >>>> >>>> On Thursday, June 11, 2015 at 9:08:39 PM UTC-4, Gerald wrote: >>>>> >>>>> The flashing LED indicates excess current is being drawn by the >>>>> processor. This can be related to damaged I/O pins or power supplies that >>>>> are not well regulated.. >>>>> >>>>> Gerald >>>>> >>>>> >>>>> On Thu, Jun 11, 2015 at 4:38 PM, <ahad...@gmail.com> wrote: >>>>> >>>>>> I have the same issue, already 3 boards has died. >>>>>> any solution, i tried to use optoisolator/pwm and noting. the BBB is >>>>>> a bad board. >>>>>> >>>>>> >>>>>> >>>>>> Le mercredi 25 février 2015 18:03:24 UTC+1, mdtsa...@gmail.com a >>>>>> écrit : >>>>>>> >>>>>>> Identical problem this morning: BBB boots fine when powered by USB, >>>>>>> but not when powered by a 2.0 mA rated 5.0 V DC power supply (nicked >>>>>>> from >>>>>>> some other device). BBB power LED blinks continuously. This power >>>>>>> supply >>>>>>> has worked with this BBB in the past. >>>>>>> >>>>>>> Mike. >>>>>>> >>>>>>> On Friday, January 23, 2015 at 8:44:59 PM UTC-8, 1127...@gmail.com >>>>>>> wrote: >>>>>>>> >>>>>>>> I had a similar problem- my power LED would just continue blinking >>>>>>>> when connected to a 5V power source. This meant there was something >>>>>>>> wrong. >>>>>>>> First, I checked if my BBB was still alive. To find that, I connected >>>>>>>> my >>>>>>>> board to a computer via USB. Surprisingly, this time power LED turned >>>>>>>> on >>>>>>>> normally. Then to make sure that everything was properly, I ran some >>>>>>>> program as given in the BB website >>>>>>>> http://beagleboard.org/getting-started. I was happy to see, the >>>>>>>> programs on the website worked just fine on my board. Thus, I was able >>>>>>>> to >>>>>>>> conclude that strangely, my BBB board didn't like 5V external power >>>>>>>> source! >>>>>>>> >>>>>>>> On Friday, November 22, 2013 at 6:41:41 AM UTC-8, Bert Lindner >>>>>>>> wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> Just had a 5V powered Beaglebone Black seemingly die on me. First >>>>>>>>> the power led kept blinking, then after removing the (BB Toys CAN) >>>>>>>>> cape the >>>>>>>>> power led would flash just once after applying power. Looking back in >>>>>>>>> previous threads this seemed to mean I killed the board somehow; >>>>>>>>> there was >>>>>>>>> also a GPS module attached to one of the UARTs and a probably power >>>>>>>>> hungry >>>>>>>>> USB wlan stick that I'm trying to get to work, so a power hungry >>>>>>>>> setup. >>>>>>>>> >>>>>>>>> I was ready to declare it dead, it remained just flashing once >>>>>>>>> after repeatedly unplugging and reattaching the power supply. >>>>>>>>> >>>>>>>>> However I noticed the single power led flash would also happen if >>>>>>>>> I pressed the power button (leaving the 5V plug in). Doing that >>>>>>>>> repeatedly >>>>>>>>> seems to have revived the board, will see if new problems occur. For >>>>>>>>> now it >>>>>>>>> behaves normally. >>>>>>>>> >>>>>>>>> Is this expected behaviour? >>>>>>>>> >>>>>>>>> Best, >>>>>>>>> >>>>>>>>> -Bert >>>>>>>>> >>>>>>>>> -- >>>>>> For more options, visit http://beagleboard.org/discuss >>>>>> --- >>>>>> You received this message because you are subscribed to the Google >>>>>> Groups "BeagleBoard" group. >>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>> send an email to beagleboard...@googlegroups.com. >>>>>> For more options, visit https://groups.google.com/d/optout. >>>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> Gerald >>>>> >>>>> ger...@beagleboard.org >>>>> http://beagleboard.org/ >>>>> >>>> -- >>>> For more options, visit http://beagleboard.org/discuss >>>> --- >>>> You received this message because you are subscribed to the Google >>>> Groups "BeagleBoard" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to beagleboard+unsubscr...@googlegroups.com. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> >>> >>> >>> -- >>> Gerald >>> >>> ger...@beagleboard.org >>> http://beagleboard.org/ >>> >>> -- >>> For more options, visit http://beagleboard.org/discuss >>> --- >>> You received this message because you are subscribed to a topic in the >>> Google Groups "BeagleBoard" group. >>> To unsubscribe from this topic, visit >>> https://groups.google.com/d/topic/beagleboard/jBFshjlPeHI/unsubscribe. >>> To unsubscribe from this group and all its topics, send an email to >>> beagleboard+unsubscr...@googlegroups.com. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to the Google Groups >> "BeagleBoard" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to beagleboard+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > Gerald > > ger...@beagleboard.org > http://beagleboard.org/ > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to a topic in the > Google Groups "BeagleBoard" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/beagleboard/jBFshjlPeHI/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > beagleboard+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. 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