Rain or water sensor?

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=66632
Printed Date: July 19, 2025 at 2:49 AM

Topic: Rain or water sensor?

Posted By: wester97
Subject: Rain or water sensor?
Date Posted: November 19, 2005 at 11:39 PM

Anyone know of a water sensor that I could use so that i dont end up leaving my windows cracked and have a freak storm soak my car again?

Obviously going to be used with a window module and timer ....

Thanks!!

Replies:

Posted By: dualsport
Date Posted: November 20, 2005 at 1:19 PM

Sounds interesting-
There's probably a commercial one out there, but something like this should work, if you can't find it and want to try making it yourself from a few cheap components-
posted_image

Component List >>>
1uF cap
1N4001 diode
RELAY
BS170
10M, 1M, 330 ohm resistors
14011 CMOS NAND gate

Maybe use a pair of header pins for the contacts, which you would put in a shallow tray that would collect the rain water- the idea is that when the water touches both pins, it'll conduct and short the two together, triggering the circuit and briefly closing the relay.
It outputs a single pulse, and won't repeat until the contacts dry out and open the circuit again.

Posted By: dualsport
Date Posted: November 20, 2005 at 1:23 PM

By the way, if your trigger input doesn't really require any current drive, you could probably delete the BS170 and relay shown, to cut down on the parts count.

Posted By: wester97
Date Posted: November 20, 2005 at 5:07 PM

Wow. Really makes me wish I was an EE!

Posted By: dualsport
Date Posted: November 20, 2005 at 9:17 PM

Sure enough, a google search shows something tailor made for the purpose: rainmain

Posted By: Ween
Date Posted: November 20, 2005 at 9:50 PM

hi,

if i recall correctly, Micro-sciences/Twindows had an add on piece to their sunroof

controller modules that performed a rain sense(auto-close) and temperature sense(auto-vent).

the rain sensor portion was a circuit board (gold plated for corrosion protection) that was installed

near the windshield. also i'm pretty sure i could trigger the auto-close input of their window modules

using the above circuit board directly connected to that particular input.

more input for you.

mark