I am looking to build or preferrably buy a miniature waterproof switch for a "waterbot" I'm working on, but I have come up empty handed in my google searches. I only found one that might be usable, but wondered if any of you might know where I can find one. All I'm looking for is a waterproof, push button "on/off" switch. Ideally it would be like the reset button on my wireless router where it's sunken and you need to use a pen or something to turn it on and off. Any ideas? Please help!

I'd also be interested if anyone knew a cheap product that might have one of these switches that I could take it from....

I'd suggest using a regular switch inside the waterproof housing, with some sort of "soft spot" where you could just squeeze or press the skin to hit the switch underneath. Another option would be a pin or rod going through the hull to the switch inside (waterproofed with grease like a propeller shaft). Depending on the amount of submersion, you might not need much more than a rubber cover like the boot on a car's gear shift.

Reed switch with an external magnet? The magnet could be loose, or slid or rotated into place. Guaranteed to be waterproof.

Maybe slipped into one of those "coin cell" holders to keep it in place? Not the plastic ones, but the metal "pocket" kind that just presses the cell against the PCB...

Thanks for the replies! I've ordered probably 15 different switches (including the reed switch) to try out, but I'm still looking. I can't seem to find a SPST latching pushbutton switch as small as I would like. I really don't want the push button over 6mm, but I'm starting to think that might not be possible. My waterbot is basically a small, hollowed out submarine and it will be completely submerged when in use. I've decided to give up on the waterproof switch and just find the smallest one and try to waterproof it myself. I've found a lot of momentary switches that meet my size requirement, but I need a switch capable of turning on and off my waterbot. I'm open to any other products/ideas anyone may have. Thanks again for the replies! At least it feels like I'm finally moving forward with this idea.

Since I have been unable to find a switch to meet my needs, I have another question. Is there an easy, inexpensive way to just skip the switch altogether and just use water to complete the circuit? So, once I put my WaterBot in the water, the water would complete the circuit?

The problem I see with that is the inability to shut it down, aside from "catch it, take it out of the water, and dry it off"...

Unless your case is all-metal, I think the magnet-plus-reed switch is the best (most waterproof) bet. Or at least a magnet-plus-hall-effect-sensor that cuts power to the drive system you're using. A little clip can hold the magnet in place without fuss, and just pop the magnet out to disable (at least some of) the robot.

Yes, it's me again and I think I found what I need, but it's a little more $ than I had hoped to spend and I can't seem to find a place to purchase it. It's from Meder and it is part number MK6-4-E. Anyone know where I can order that part and not have to order 100 at a time? Thanks!

The MK06-4-B is available from Mouser. Are you a bit flexible?