Let's Make Robots!

Water Present Sensor?

I seem to have a lot of water on my floor... From accidental uncleaned spills or melting dropped ice cubes. My last bot went over un unseen puddle of water and guess what... it died. So I was wondering if anyone knew of a cheap sensor that could detect water or even a way to make one. Thanks in advance.

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I'm sure it would be harder to implement than my simple idea.. but just using 2 Wires and a pull-down resistor in there, when they both come in contact with water (causing the input pin to go HIGH), then have some code based off if that sensor completes it's circuit, then set a command to drive around, like turn left 90 degrees, drive forward, turn right.. etc etc

 I'm sure it's not THAT simple, but the same idea was used in Zanthess' Mr Tea. She used 2 wires to show if the water was going to over flow, turning off something. Here's the link to Mr Tea. below.


Best of luck, let us know if you figure anything out


A while ago I made a simple 2-contact touch sensor using something like this:

Water Sensor

The same arrangement would work fine for a water sensor too, or you can flip it over and use a PNP transistor to reverse the output. The advantage over using just two wires is that the sensitivity is higher, but you can also adjust it by changing the resistor values.

Ok yes you may not beleive me but look it up

only salt water is conductive. But since humans have salt on their skin any liquid because a little slaty with our touch. However i think water may conduct a bit but i dont know for sure.

I'm pretty sure all water will conduct, just not as well depending on the type(ionized, unfiltered, etc).
water coming from my kitchen sink does conduct, not too well though
Put salt on the wires
Lol, not really much of a permanent solution =D

Put a sponge bumper around your robot.

Or test your robots out in another room. (Not the bathroom.)

i could put a sponge but that sort of defeats the purpose for me. i dont run my bots in the bathroom by the way.