Help...Mimicking a windshield washer motor with a delay..

Feb 21, 2004 6 Replies

Hello there Folks.



I need some advice as to how I would make a small dc motor (say that ran on



2 c cell batterys) that would mimic a windshield wiper motor.


  1. This motor would have to lift a .25 pound weight



  1. The motor would travel 1/2 a turn in 10 seconds, then travel back 1/2 a turn in 10 seconds, and then delay for 1 minute.
  2. It would be cool if the delay could be set to 30 second intervals from 1 second to 5 minutes.

Thanks ...



Brent


Brent, if this were something I had to do, I would make a cam that the motor could drive. The cam would do two things for you- a) it would provide the reciprocating sweep action for your wiper arm, and b) it would allow you to mount a microswitch or other sensing device to tell it when to stop because it had reached the end of travel. Now, by adding a simple electronic timer, you can control the delay time in any manner you wish. It simply sees the microswitch that indicates "end of travel", runs its delay, then applies power to the motor. It will then wait for the microswitch to close again before running the delay time again.

Cheers!

Chip Shults

You could get an appropriately sized RC servo (plan on 4 or 5 batteries), connect it to some controller (BASIC, OOPIC, PIC, etc.). Then it's all software.

Mitch Berkson

Hi there Mitch..

Where would I start?

The appropriately sized RC servo (is this the DC motor?) would only have to lift something the weight of a cdrom..

What are the controllers....

Sotware, does this come with the controller?

Is there some kind Of Kit I would buy?

Sorry, Brent- I typically make this sort of thing on the fly. I would definitely use a gearhead for the motor, because otherwise you will have very little torque to deal with. So there are no real "drawings" of any sort to work from. But I can point out a mechanism for you to learn from. Ever see a wheel with a shaft sticking out, off-center? Now, attach an arm to that shaft and as the wheel turns, the arm can reciprocate. Picture the mechanism on an old style steam locomotive that turns the wheels. Windshield wipers have similar mechanisms, or they have a wheel with a slot inside. This is the same concept, but now the arm has the pin and the wheel, when turning, guides it back and forth. I'm sorry that I can't be more helpful, but take a look at the "how stuff works" site and you can surely find many examples of mechanisms that will do what you want.

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Cheers!

Chip Shults

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