Toyota Rain Sensing Windshield Wipers

dug1967 · 02-11-2005, 11:42 PM

Have you guys seen the Avalon comercial where they mention wipers that come on automatically when it starts to rain????

Pretty cool....

I have been mulling over a simlar idea for a few years now, except I want the windows to be put up when it rains and the car is parked at work.... I leave the windows down in the summer when I am at work.... I hate a 150 deg car experience at the end of the day....

But in Texas it can (and will) rain at the drop of a hat... without warning....

Doing a Google search for "rain sensor" it is easy to make a little PC board and circuit to sense the rain..... and then power up the window motors, etc....

But I was wondering if anybody knew how Toyota did it with the Avalon..... a nice clean system would be cool...

Anybody know?

turbocad6 · 02-11-2005, 11:49 PM

one clue I can give you is that lexus has the rain sensor built into the windshield, bmw, benz & jag, infiniti do the same......haven't looked into this further, but they all have sensors that are built into the windshield. I have seen add on aftermarket(dei maybe?) rain sensors though I think, start searching high end security accessories....good luck..........

0l33l · 02-11-2005, 11:55 PM

Would help knowing what car you have.

One problem with your idea: POWER! The computer cannot be in standby if the rain sensor is to tell it something. That means that the computer will have to be on from when u start work till when you finish. Not a very good idea for batteries.

n8scstm · 02-12-2005, 12:41 AM

Ive seen sensors that sense water that are used for sprinkler systems. It turns them off in the rain. Its basically a sensor hooked to a relay. If you could get ahold of one of those you could make your own circuit pretty easily.

Vchat20 · 02-12-2005, 12:56 AM

i remember seeing an old car show on TNN where they were showcasing a device which was basically a sensor mounted on the inside of the windshield behind the rear view mirror and it was wired into the wiper system and essentially did what the avalon does, but on cars that cant. beyond that, i have no clue about the product.

one thing i can suggest as far as power is concerned (which ive seen someone else here suggest) is to have the computer running all the time (or atleast the times you wish the rain sensor to do its work), and have the computer wired to the ignition so that it will start the car every 5 minutes or so and run it for a couple minutes to keep the battery charged.

djmickyg · 02-12-2005, 01:06 AM

i work for bosch and bosch makes em .. i neer thought of getting a hold of one to play with

there all mounted on the windscreen, maily behind the rear view mirror. it looks like a dark purple/blue arear thats maybe 5cm square.

they work by emiting ultraviolet (i think ultraviolet) like onto the windscreen and when the window is dry the layers on it will be flat the light will reflect off the top surface and bounce back at the unit and it knows there is no rain
when rain falls on the area on the sensor the light goes true the window into the ball of rain and cus the rain ball is round not flat it is reflect off an on a different agle and the unit wont pick it up sencing there is rain.
the more light that is not reflected back the heaver the rain is

sfay93 · 02-12-2005, 01:10 AM

Quote: Originally Posted by djmickyg

i work for bosch and bosch makes em .. i neer thought of getting a hold of one to play with

there all mounted on the windscreen, maily behind the rear view mirror. it looks like a dark purple/blue arear thats maybe 5cm square.

they work by emiting ultraviolet (i think ultraviolet) like onto the windscreen and when the window is dry the layers on it will be flat the light will reflect off the top surface and bounce back at the unit and it knows there is no rain
when rain falls on the area on the sensor the light goes true the window into the ball of rain and cus the rain ball is round not flat it is reflect off an on a different agle and the unit wont pick it up sencing there is rain.
the more light that is not reflected back the heaver the rain is

I think this is correct. My wife's Chrysler 300 has this feature as well. The harder it rains, the faster the wipers go.

mushin · 02-12-2005, 01:43 AM

For power: I wouldn't go though the carputer for this. There's really no need, the logic is so simple (rain -> close power window button circuit for x seconds,) the computer is superflous. You don't even need a PIC. The rain detector tied to a timer circuit tied to a relay should do the trick. The idle power draw will be pratically nill (and you could probably make it actually nill if you wanted.)

I'm planning on adding a rain detector, but rather than auto-up the windows, it'll be tied to a remote control to sound an alarm to my desk at work - I have a manual-top convertable, so windows by themselves aren't going to do much good

turbocad6 · 02-12-2005, 12:57 PM

Hmm, I guess I just assumed the rain sensor was built into the windshield because I have changed quite a few, & I know that you must specify whether the vehicle has rain sensor or not, I'm used to seeing defrosters built in to winshields as well as anntennas, so I just assumed..............but after thinking about this further I realize that although the winshields are different, it's just to accomodate the rain sensor mounted behind it.

sorry for the miss-information I guess I just didn't pay enough attention to the actual rain sensors, although I do remember one car did have a strange box type thing attached to the mirror mounting area, that must have been the rain sensor.......

grepzen · 02-12-2005, 01:10 PM

Try another approach:

:: default position of windows == rolled up (security)
:: when temp (outside) > x then "vent" (roll down) windows 1/2"
:: when temp < y roll up windows (rain would cool outside temp below y)

They already have complete kits for this, & you get to set x and y values.

rando · 02-12-2005, 01:12 PM

Quote: Originally Posted by 0l33l

Would help knowing what car you have.

One problem with your idea: POWER! The computer cannot be in standby if the rain sensor is to tell it something. That means that the computer will have to be on from when u start work till when you finish. Not a very good idea for batteries.

This is not strictly true. With just a little bit of circuitry, it would be possible for the rain sensor to turn on the computer when it need it to do something. Moreover, he didn't mention if actually expected his PC to participate in this at all.

DeltaFX · 02-12-2005, 02:33 PM

Ultraviolet ? Me think it's infrared, UV-sensors aren't that common

Vchat20 · 02-12-2005, 08:26 PM

also, our windstar has a feature similar to this, although i doubt it is based on the rain amount, rather its probably speed based. basically you have to go through a long set of instructions listed in the owners manual to activate it (and you have to reactivate it every time you start the car). more or less it involes changing the ignition state and using the wiper controls and just properly coreographing(sp?) it all.

scott_fx · 02-12-2005, 08:34 PM

do some research on qtouch ic's I'm using them for a different applications but the watter on the windshield would cause a change in capacitance and trigger the ic. this would be the sensor...the logic is in your hands, i do like the auto pc power up because you could have it do some other cool things!

0l33l · 02-12-2005, 11:27 PM

Quote: Originally Posted by rando

This is not strictly true. With just a little bit of circuitry, it would be possible for the rain sensor to turn on the computer when it need it to do something. Moreover, he didn't mention if actually expected his PC to participate in this at all.

True, but that's more complicated...

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