Waterproofing arduino and lines out

I'm planning on building an LED-lit helmet for a 10k race. I'll be wiring up a bunch of Neopixel strips to an Arduino 101 with separate power cables to battery packs. I will be using all 14 of the digital outs, along with other connections.

The issue is that everything (except the battery packs) will go inside the helmet, with only a small amount of clearance, where it will be exposed to sweat and possibly rain blowing into the helmet from mounted fans.

How do I go about creating a waterproof enclosure with all of those cables coming out of the arduino? I've heard of shrink-wrapping the connection between the cables and LED strip cases, but how should I be waterproofing the cable-to-pinout connections on the board, with the enclosure or otherwise?

Ideally, I would like to be able to dismount the arduino from the enclosure for use elsewhere. My plan for preserving the connections was to solder the Arduino side of the digital-out cables for the LEDs to a row of male-male header pins (like this https://goo.gl/mmT60f) so I can plug and unplug the entire set of 14, but how would I waterproof this? Using shrink wrapping would be difficult because of the distance between the wires, and the possible gap between the black plastic spacer on the header pin and the shrink wrap.

Why are you mounting the Arduino in the helmet? Personally I’d put the Arduino in a backpack along with the batteries and then just run power and data wires to the strips in the helmet.

I'm mounting it in the helmet because I'd like the design to be as clean as possible, without too many obvious wires. The second reason is because I have even less of an idea how to mount these outside the helmet without being seen; using a normal backpack is not an option because I've had bad chafing issues with them in the past regardless of weight.

Just get a hammer and knock some holes in your scull so you have more room for the arduino etc.

That the same effect as what will happen when you have a fall off the bike and crash onto the helmet with the Arduuino and batteries etc in between

A safety helmet is designed to exact tollerances and drilling or fitting extra parts onto them, unless designed for is rendering them ineffective; fitting things inside is madness.

Why not use a Promini? Surely a 32-bit processor is overkill for controlling some LEDs?

Otherwise, put it all in a ziploc bag.

Anyways, putting holes in the scull would surely let water in https://en.wikipedia.org/wiki/Sculling

"shrink wrap"? Do you mean heat-shrink tubing? If so, get epoxy filled tubing so the chances of water getting in are minimized.

Paul

Normally you would put the board in a small polycarbonate (or like) box with the wires hanging out and fill it with potting compound (epoxy). However this would be too bulky for your helmet.

The alternative is to use a 'conformal coating' which will result in minimal increase in profile while achieving waterproofing.

https://en.wikipedia.org/wiki/Conformal_coating

As previously mentioned, a pro-mini would be a much better sized board to use.

Use something smaller than a 101! There are plenty of smaller boards with plenty of pins.

ricky101: Just get a hammer and knock some holes in your scull so you have more room for the arduino etc.

That the same effect as what will happen when you have a fall off the bike and crash onto the helmet with the Arduuino and batteries etc in between

A safety helmet is designed to exact tollerances and drilling or fitting extra parts onto them, unless designed for is rendering them ineffective; fitting things inside is madness.

This ^ precisely.

Qdeathstar: Why are you mounting the Arduino in the helmet? Personally I'd put the Arduino in a backpack along with the batteries and then just run power and data wires to the strips in the helmet.

Parenthetical: I'm mounting it in the helmet because I'd like the design to be as clean as possible, without too many obvious wires. The second reason is because I have even less of an idea how to mount these outside the helmet without being seen; using a normal backpack is not an option because I've had bad chafing issues with them in the past regardless of weight.

Umm, so where are the batteries going to be? Mount the Arduino with the batteries, not on or in the helmet, as suggested by Odeathstar, and sleeve the cables together so that there's a minimal of cables, for better visual appeal.