Reversed Power on VIN / GND

[Prodigal]

I made the mistake of plugging 6v power into the GND port on the Moteino.  There was a small puff of smoke. 

I am able to power up the Moteino using either the USB adapter or through the VIN pin.  I can also upload a sketch to make an LED blink.  I have not tested the transceiver so I am not sure if that works or not.

Three questions:

1) Is there a way to prevent this from happening in the future?  Can I simply put a diode in front of the GND pin so current only flows out of GND and not in?

2) Is there a diagnostic sketch that will test all the different features of the Moteino?

3) If there is damage on the board somewhere, is there anything I can do to salvage or fix it?

Thanks,

Ken

[Felix]

You probably smoked the regulator.
There is no sketch to check for things like that
Yes you can add your own diode for that purpose. I did not include one because that would offset the regulator dropout by anywhere between 0.2-0.8V, which is a huge difference when running on battery.
I assume you have a multimeter if you fiddle with electronics, check the "3.3v" output, it should read 3.3V if the regulator is good.
If you can power it and upload sketches then run a blinky, then run the Node sketch. It should be very obvious what is not working by trying these things.

[Prodigal]

I tested the power.  Voltage from the battery to VIN is 6.2 volts.  Voltage out of the 3.3v pin is 3.31 volts.  So, it looks like the regulator is fine.  I must have pulled the power quickly enough to avoid real damage.

I'll play around with a diode on the ground line to see how that affects power to the Moteino.

Thanks for the help.

[Felix]

Well that's interesting, smoke but still working?
I think smoke is not a good sign anyway, something might still be working but then fail later...

[Prodigal]

I'll keep my fingers crossed.  In the meantime, can you answer this question: If there is damage on the board somewhere, is there anything I can do to salvage or fix it?

[Felix]

Probably, but is it worth it? They are all SMD parts, hard to get off properly.