Auto Car Wiper

How do you intend to wipe out a whole car??????????? For havens sake, the required battery power alone will be enormous.

As in windshield/windscreen wiper?

They use mechanical switches for sensors.

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what I meant is windshield wiper. sorry for the trouble. I want to make the wiper automatically switched on when rain drops to the windshield. My car is just a small car I used for electronic project. The problem is I don't know what sensor I need to use. What do u suggest?

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I think a conductive grid is usually used, don't have it "live" all the time as that'll wear ir out, just ping it for a microsecond or so every few seconds.

Bye. Jasen

Imagine if you will, the wire antenna that is laid against the inside of the windshield glass. 2 wire side by side carrying a small signal that is coupled between the wires. When the outside of the windshield gets wet, the water acts as capacitor connected to the 2 wires and thus you get more signal on the receive wire. There you have a capacitive coupling rain sensor. You can use that to activate the wipers with of course the signal and trigger circuits. Hope this gives you ideas. :)

Sjouke Burry wrote in news:4532f461$0 $2025$ snipped-for-privacy@text.nova.planet.nl:

That's why it will have an alternator on board. :-)

Puckdropper

"James Thompson" wrote in news:4a17b$45333cda$438c8521$ snipped-for-privacy@ALLTEL.NET:

That's an interesting idea. I've seen "rain detection" circuits that are basically two wires spaced a drop's space apart, and I was thinking that'd never work for a windshield. With your idea, it's possible to cover a much larger area and thus turn the wiper on when needed.

Puckdropper

Thanks guys for the help. Really appreciate it

harore

Came across a circuit the other day similar to what Mr. Thompson was suggesting. That's how I'd do it too - less problems with electrode corrosion and dirt build up giving false positives - like you'd run into with a contact sensor.

It is for a level gauge in a tank, but could be adapted for on/off indications easily enough. I doubt you'd need a crystal controlled oscillator for it, and moving the frequency higher may make it more sensitive with less electrode area . . .

Another possibility is using a mechanical humidity sensor - nylon rope webbing, under tension, seems to elongate when it is wet. Its possible to make a decent mechanical humidity sensor from horse hair (sold for violin bows) - but that wouldn't be ideal for outside.

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"I was thinking to make an auto car wiper. I want to know what is the best sensor to use for the circuit. Hope you guys can help me."

Re: You can purchase window defrost strip repair "paint" at automotive parts outlets. This is a conductive paint that is used to repair the heat strips that are laminated onto automotive windows; usually the rear window. It adheres well to glass. You could apply this to the outside of the windshield in two, closely spaced strips, to act as the sensor. When the glass between the strips becomes wet, this would provide the conductive path for your wiper activation circuit. I suppose you would have to experiment with spacing and placement of the "strips".

Dan Akers