Shoving electronics in small boxes without shorting them out

This has happened one too many times, and I had to overpay for a new robot MCU last night because the last one caught on some exposed metal and shorted out.

How would I keep that from happening? Heatshrink doesn't make sense because the MCU (RF nano) is too big. Electrical tape might work but the warmth inside the robot would weaken it over time. I could cover it in hot glue I guess, but that would take forever and add a lot of weight to a bot that has to weigh <1 pound. It's already at 0.95.

I've already taken a couple of precautions, by clipping any excess pins that weren't used by the robot, but clearly it wasn't enough.

Get some larger heatshrink ?
Has the board got any mounting holes ?

Kapton tape is a common choice for robust insulation that's resistant to heat. But usually you just mount the boards on stand-offs to avoid the problem completely.

post a few so we can see the thing and offer some advice based less on guess work.

Don't use conductive boxes, plastic insulates & is lighter.

But then you have no screening/shielding... Kapton sticky tape is available in a range of widths.

Its common experience that electronic equipment that works fine on the bench will fail as soon as the lid is fitted to its enclosure. The extent of the failure depends on
how hard it is to reopen the enclosure
how much effort has been put into getting it working,
the total value of the parts
and how essential it is for the device to work.


@johnerrington Yes.
@MarkT I forgot about that stuff! EDIT - Ohhhh, but it's really expensive.
@missdrew The box is 3D printed plastic. It shorted on some bolts that I can't omit from the project.
@UKHeliBob Yeah, it has mounting holes, but they are the same size as the ones on the Arduino Nano, so not very helpful. Larger heatshrink makes sense but the other issue is that the board has pins soldered on, instead of a direct wire-to-board connection.
Rf nano v3.0 micro usb module atmega328p qfn32 5v 16m ch340 integrate  nrf24l01+2.4g wireless imme Sale -

Thanks for posting a pic of the board. Whiles I am delighted to have confirmed for me the MCU you are using, I am more interested, at this point, on seeing an image of the project. I'd like to see where things are and at what point the short happens and other shots that may help us help you.

Ah. I'm at school at the moment, so the only photos I have access to are the outside, and those are fairly outdated. The photos I have of the inside are REALLY outdated. I'll show what I have of the outside (the really old inside photos won't help) and then snap a photo of the up-to-date thing when I get home.

So those two blue motors are held in by long brass bolts that are fastened on the other end. That's what the Arduino shorted out on this time, but I think some other exposed metal (switch terminals, other PCBs, other screws, etc) could be a problem too if they come in contact with the wrong part of the board.

EDIT - This is very different from what the bot looks like right now, but it shows where everything is.

I follow the philosophy put forth in reply #3.

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Why. Plastic such as Nylon would work well at the power level your motors are producing.

Tape or some covering like nail polish, will only wear through or off. You should look to physical mounting improvements and parts spacing tolerances.

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I didn't know that nylon bolts existed when I started. Maybe an upgrade in the future for weight/smaller likelihood of shorts.

So I thought about zip-tying the nano to the brushless ESC that runs the flywheel out front, but it ended up holding down the reset button. Maybe I should desolder it and reset the board with a piece of metal? Or tie it on the other way and re-solder the pins upside-down (pointing up)?

I do not know. From the images posted so far, I see 2 drive wheels, a spinning slasher wheel, some blue thing, some black cover, a few wires, and a white case. I also, see a few screws and bolts. I'm unable to make a judgement call on what to do or not do with the supplied images.

These ones weren't going to be useful. I'll post more, but it will be at 6:00 or 7:00 because my bus schedule is dog crap.

EDIT - 6:00-7:00 EST.

Cut a piece of rubber so it forms a wall around the reset button to prevent accidental pushing. Glue that to the board.
Get a piece of cellophane - nice selection in flower shops, or just use the wrapping from a cigarette box, choko candies, etc. Wrap the board in it along the long sides, use a piece of scotch tape to hold it. Cables go out from the short sides, under the USB connector and the antenna.

So just-

Cover the board in stuff? I'm going to use the dead board as a test dummy so I can just kind of test stuff without worrying about killing the board. I'll definitely look at some of these, especially the cellophane idea.

Wifi boards get warm. I would not recommend putting too much tape over them. They could overheat. Especially when tucked away in a box.