light sensors and remote revving

Well I never really felt the need for a rain sensor...I can usually tell it's raining by the water falling from the sky..lol.

But the cheapest way I could think of would be to install a shock sensor to the windshield.....adjust the sensitvity with a garden hose. Sounds funny but it should work. Send the output trigger to a relay to do whatever you wish to happen during a rain.

If your wife was banging on the OUTSIDE of the windshield..she would deserve at least a smack from the wipers...lol

You would need something that can detect the thumping of rain on the windshield for this to work so I think a shock sensor is the best for that if going cheap.

Anything else would require a way to pick up the moisture, I don't have any ideas for a cheap way to do that which would be reliable...and where to mount it as well might be a problem.

The way the factory rain sensors work is by sending an IR beam through the windshield.  If there is moisture on the windshield the beam will reflect back.  I'm guessing they are fairly sophisticated as you don't want false alarms, yet you still want them to react faster then a human could.

Well now that we are on the subject of rain sensors..heres some interesting info I picked up...

In 1958, the Cadillac Motor Car Division of General Motors experimented with a water-sensitive switch that triggered various electric motors to close the convertible top and raise the open windows of a specially-built Eldorado Biarritz model, in case of rain.

The first such device appears to have been used by General Motors, for that same purpose, in a concept vehicle designated "Le Sabre" and built seven years earlier, in 1950-51.

Nowadays, rain sensors are integrated in a system to automatically start the windscreen wipers (intelligent windscreen wipers).

Most common rain sensor implementation is based on prinicple of total internal reflection: an infrared light is beamed at a 45-degree angle into the windshield — if the glass is wet, less light makes it back to the sensor, and the wipers turn on. (you hit that one KPierson)

Yep..definatly sounds sophisticated...Not something a "hobbiest" might be able to accomplish inexpensivly with any relaible results.

There is an aftermarket device I found called "Rain Tracker". It retails online for 150 dollars.The Rain Tracker uses beams of infrared light to sense how much water hits the windshield.  It constantly adjusts the speed of the wipers so that they run just often enough to keep the windshield clear-- from all the way off to (most applications) high speed.  This frees the driver from that task, reducing driver distraction.  And driver distractions is the cause of 26% of all fatal crashes, says NHTSA.  The model RT-50 Rain Tracker controls the wipers in a full range of operation, from fully off, through intermittent and steady slow, and on up through high speed (in most applications) if that is what is called for.

Talk about scare tactics...lol...This is trying to get people to believe 26% of all fatalities on the road are caused by turning on the wipers..although it doesn't say that directly..it is misleading.

I have never even thought of this as I never felt it a big deal to switch the wipers on when it rains..but now my interest is sparked. I am going to experiment with different types of sensors and see what happens. I need to find something that can discriminate the resonance of rain on the windshield vs. road vibration (combined with some kind of moisture sensor I will probably need to build myself and place properly) ..and I need it to cost WELL under 150 dollars to build this or it's a waste.

I'll post results.

Who woulda thunk...lol