the problem is I keep blowing NANOs when connecting the Lipo (2 so far, no smoke but the 328 processor gets very hot and then stops working), before i connect my last one can anyone suggest any extra precautions I should take?
I should add that both Nanos powered up fine 2-3 times and ran the demo reel 100 code perfectly before giving up.
I am only guessing that there is a voltage differential between these 4 separate GND wires and the GND pin on the Nano. Easily checked with a voltmeter without connecting the Nano and burning it up in the process.
The DC-DC converter link provided does not make it clear ( at least to me ;- ) that the IN and OUT GNDs are common.
The nano Vin is rated for 7-12v. If your lipo is fully charged it will be 12.6v and may burn out your regulator in the nano. Definitely get another of the 5v regulators and use that to power the nano.
Maybe something isn’t connected the way you intended? Posting photos might allow an opportunity for someone to notice if there’s simply a wiring mistake.
Thanks for all the replies.
First of all here’s a pic (for what its worth). unfortunately i cant get to most of that now. after the first couple of test runs i proceeded to fit the rest of the spa section across the middle.
I checked for shorts continuity and polarity before sealing it also.
The Grounds are common throughout i (have just checked again with the limited access available).
I had read about the recommended 7-12v for VIN but it also stated an absolute limit of 6-20v
I have just checked the voltage of the lipo in use following the failure of the second nano and its only reading 11.6v.
A postmortem on the nanos revealed that the on board regulators have definitely given up one is outputting 2.5v and the other 10.7v
Think I may start digging away at some foam to pickup a 5v from one of the regulators.
Also if anyone is interested the wing is a flite test mini arrow (plans adjusted for 3mm depron)
Just to clarify the first nano had been connected with all the leds working as they should and then disconnected at least twice (most likley 3-4 but a wasn’t counting) before failing as soon as the lipo was plugged in on the final attempt.
The second one also followed a near identical pattern.
I always power the LED FIRST and after a second or two then power the the Nano
Out of the same 5v power supply
When to turn thing off, the Nano Off First and the the Led
This way I am sure that the Nano 5v supply rail is not affected by the high current of the leds
Also I put a diode between the lipo and Vin just to be sure that the Nano only receive power from the battery and not try to feed the power to the leds
Is the circuit diagram complete? If you’re also powering an electric motor, the inductive spike when the motor shuts down could kill the nano. What connectors are you using? I once make the mistake of using a four-conductor barrel jack for a long LED strip. Unplugging that without first removing power killed a Teensy.
@John_Corbett It was complete at the time of writing, it was mid build so I hadn’t added any of the other gear (motor esc servos etc)
I have also experienced problems when unplugging with the power applied (only fried the first pixel though) all the connections on this build are soldered.
I have taken @marmil s advice and picked up 5v from one of the other regulators.
No fried nanos so far…
