Posted by Bill Raymond on February 6, 2009 at 10:07am
Hey guys, I was setting up my autopilot system for my senior thesis "Building a UAV for Remote Sensing and Cartographic Applications" when I guess I burnt it out. No power to the board, including direct power, and yes i switched the jumper. :-(.... The whole board seems toast. I ordered two new boards today. I followed the wiring diagram and all. I'm thinking there was a surge somehow. If you guys have any ideas let me know....P.S. The programers won't even read the board :'-( Take care and keep up the good work...I'll be posting pictures soon
It doesn't necessarily, but it does help for sizing/payload planning, plus I'd rather set the first one up using a known good configuration. Just call me paranoid chicken... ok please don't!
No idea of amp load, I'm afraid. I've got all the sensors and such, just haven't bothered to hook them up yet. Why does it matter? (Ardupilot doesn't care)
Chris,
Thanks for the reply. I looked right at that page too! I understand regarding attention to detail, I've not powered my board up as I've been unavailable, so I'll just double-check the soldering. Regarding the Super's setup. Do you know what type of amp load your plane uses for take-off and just cruising?
My Superstar setup is the one listed here. All Futaba equipment, standard servos.
All the ArduPilot pages have been updated to show the current version of the board, with the built-in power supply.
Most of the "toasting" I've seen is in sloppy soldering of pigtails and the like, where V+ touches data lines. That will fry a processor pretty quickly (I've done it myself). At $25 a board, it's hardly worth trying to replace the chip; might as well just get another board and be more careful the next time.
Clearly folks have had success in completing the setup of these boards. I'm curiouse is the "toasting" occuring during the flashing process or is it during later setup?
@Chris - Can you share the planes setup you used during flight testing? I'd like to compare your setup to what I'm planning on using. Interested in motor, esc, amp draw (high load and low load numbersif possible), the model/type of servo used on the rudder.
Anyone - If/when folks use the earlier board or one of the ones they setup from the pcb, is it just safer to get a voltage regulator to run through? Any suggestions on one to use?
bGatti asked whether servos tolerate a reverse connection. Once I managed to kill one of my servos this way. I have a small servo tester circuit with a CMOS IC on it, and I connected a HITEC hs55 to it- reversely :((( The tester survived but it did't take a half second and the servo died. Its chassis was pretty warm.
Just to be clear, boards made after 1/26 have a built-in voltage regulator. (You can see it here). On those boards, if you want to use an external battery, solder a bridge over that solder jumper and connect the battery to the BATT +- pins.
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After a quick look at the board, It appears a voltage regulator could be plugged in - in place of the power select switch. Connect vin to the SVR5 pin. Connect vout and ground to the appropriate power pins of either programming plug. The use of a low dropout regulator requires a higher voltage from the BEC. moving the system voltage to 3.3 would solve the problem - but that would be a larger change.
This is not to jump ahead of the diagnosis.
I'm suspicious of the combination of the diode with the noise of the servo motors - and propose that a regulator would solve the issue. A zenor clamping diode could help, as well as some induction between the servos and the mpu.
I created a sim of this power system in 5Spice ( a diode and a capacitor) I added small resistors and inductors to represent the wire lengths and created a rising voltage. Then I injected noise into the power inputs - to represent motors. Under noisy conditions, the voltage rose from 6 to 7.5. I suspect a high voltage motor feedback from a servo motor would pass directly through the diode and into the chip. caveat emptor: the sim is far from perfect.
Comments
Thanks for the reply. I looked right at that page too! I understand regarding attention to detail, I've not powered my board up as I've been unavailable, so I'll just double-check the soldering. Regarding the Super's setup. Do you know what type of amp load your plane uses for take-off and just cruising?
My Superstar setup is the one listed here. All Futaba equipment, standard servos.
All the ArduPilot pages have been updated to show the current version of the board, with the built-in power supply.
Most of the "toasting" I've seen is in sloppy soldering of pigtails and the like, where V+ touches data lines. That will fry a processor pretty quickly (I've done it myself). At $25 a board, it's hardly worth trying to replace the chip; might as well just get another board and be more careful the next time.
@Chris - Can you share the planes setup you used during flight testing? I'd like to compare your setup to what I'm planning on using. Interested in motor, esc, amp draw (high load and low load numbersif possible), the model/type of servo used on the rudder.
Anyone - If/when folks use the earlier board or one of the ones they setup from the pcb, is it just safer to get a voltage regulator to run through? Any suggestions on one to use?
.
This is not to jump ahead of the diagnosis.
I'm suspicious of the combination of the diode with the noise of the servo motors - and propose that a regulator would solve the issue. A zenor clamping diode could help, as well as some induction between the servos and the mpu.
Anyone else have thoughts?