# Wiper motor controller finished



## Otaku

Hi all,
I finally finished the wiper motor controller circuit I've been working on. This circuit will allow the motor to rotate 180°, pause for a few seconds, then rotate another 180° and wait for the next trigger. I'll be using it for opening and closing the lid on a "Buried Alive" coffin. Here's a short video of the circuit in action.

Wiper motor demo video by Otaku1031 - [email protected]@[email protected]@http://vid73.photobucket.com/player.swf?file=http://vid73.photobucket.com/albums/i231/Otaku1031/[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@i231/Otaku1031/Wipermotor


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## gmacted

Good job Otaku!


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## psyko99

Nice job Otaku. Since the wiper moter is not a stepper motor, does the start and stop position ever get out of alignment?


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## Otaku

The start/stop positions are controlled by an optotransistor that "sees" a reflector mounted on the motor shaft. When the reflector bounces the IR beam back to the detector the motor power is cut. Momentarily disabling the opto starts the rotation. After 5 hours of testing (cycling every 30 secs) the start/stop position didn't vary by more than a couple of degrees. It's not quite as accurate as a stepper, but for opening and closing coffins, doors etc, its more than sufficient. The cost of the board components is ~ $17.00.


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## Dr Morbius

AWESOME!!! The applications for this are mind boggling.


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## dave the dead

Very cool...very creative! Sure wish I understood how you do what you do.....
Thanks for sharing. I can see lots of uses for this kind of circuit.


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## Otaku

Thanks for the kind words, all! And many thanks to all those who advised me during the frustrating design phase - couldn't have done it without ya! But that's what these forums are for, right?
I can picture doors, coffins, mailboxes, linkages of various types being actuated/extended by a wiper motor. Anything that doesn't present too heavy a load for the motor should work with this system. The timing circuit can be designed and adjusted to allow multiple extensions/retractions in a single cycle, too. This design is pretty basic; someone with PIC and counter experience should be able to run with this and optimize it into something that can be programmed easily.


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## heresjohnny

You can do a lot with this circuit Otaku, very nice!


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## Dr Morbius

I had a thought, don't know if its possible, but would there be a way to make it turn 180 (like it does now) but instead of completing the circle have it reverse direction and stop instead?


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## Stiff Kitten

Thats great I can see it working on many different props. Now that you did all the hard work are you going to post a how to/schematic of your little creation?


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## Otaku

Dr Morbius said:


> I had a thought, don't know if its possible, but would there be a way to make it turn 180 (like it does now) but instead of completing the circle have it reverse direction and stop instead?


Good question. I hadn't considered that design; you'd need to reverse the polarity to the motor. It may be possible using a latching relay. Dammit, Doc, now I'm not going to sleep tonight!


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## Revenant

Otaku said:


> Dammit, Doc, now I'm not going to sleep tonight!


That's what these forums are for, right?


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## Otaku

Revenant said:


> That's what these forums are for, right?


LOL!


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## Dr Morbius

Otaku said:


> Good question. I hadn't considered that design; you'd need to reverse the polarity to the motor. It may be possible using a latching relay. Dammit, Doc, now I'm not going to sleep tonight!


LOL! Sorry about that. Now what about speed control?


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## Koumajutsu

Dr Morbius said:


> I had a thought, don't know if its possible, but would there be a way to make it turn 180 (like it does now) but instead of completing the circle have it reverse direction and stop instead?





Otaku said:


> Good question. I hadn't considered that design; you'd need to reverse the polarity to the motor. It may be possible using a latching relay. Dammit, Doc, now I'm not going to sleep tonight!


yeah, it should be a fairly simple trick to pull off, but I have to ask why?
with a push-rod the a half a rotation would fully extend the rod and the other half of the rotation would retract it. if you needed rotation from that, just attach the free end to a cam similar to how an oscillating fan works


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## Otaku

Dr Morbius said:


> LOL! Sorry about that. Now what about speed control?


Speed control, eh? That's a double-edged sword. You'd need a pretty fat transformer to handle the wattage, I think. The original circuit has a 10K - 10 turn pot on it to adjust the motor speed, but it's a puny 20mA gearmotor and a completely different application (driving a small Geneva mechanism). And you lose some torque when you use a resistor, as you know. There's some PWM speed control kits available for DC motors, but I've used them and the range is pretty limited. A guy I work with built a motor speed controller for a large DC gearmotor, and the transformer he used must weigh 20 lbs, no kidding, and the motor draws just 3 amps. Speed control is definitely a nice option, but could get pricey. Has anyone tried using rheostats or similar devices with wiper motors?


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## Dr Morbius

Koumajutsu said:


> yeah, it should be a fairly simple trick to pull off, but I have to ask why?
> with a push-rod the a half a rotation would fully extend the rod and the other half of the rotation would retract it. if you needed rotation from that, just attach the free end to a cam similar to how an oscillating fan works


Why? WHY?! LOL! Now THAT is the magic question. Actually, If it were able to oscillate you could use TWO rods! Think linkages, also, you could use it to make intermittent unidirectional movement like a servo. YOu could use brakeline cables to transfer motion to articulate a hand to open and close. Things like that. Just thinking outside the box. Mostly to make a return motion where gravity wouldn't work or rods would collide if the shaft kept going.


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## Dr Morbius

Otaku said:


> Speed control, eh? That's a double-edged sword. You'd need a pretty fat transformer to handle the wattage, I think. The original circuit has a 10K - 10 turn pot on it to adjust the motor speed, but it's a puny 20mA gearmotor and a completely different application (driving a small Geneva mechanism). And you lose some torque when you use a resistor, as you know. There's some PWM speed control kits available for DC motors, but I've used them and the range is pretty limited. A guy I work with built a motor speed controller for a large DC gearmotor, and the transformer he used must weigh 20 lbs, no kidding, and the motor draws just 3 amps. Speed control is definitely a nice option, but could get pricey. Has anyone tried using rheostats or similar devices with wiper motors?


Oh man, I was just kidding about that! Sorry. Interesting subject though.


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## Koumajutsu

Dr Morbius said:


> Why? WHY?! LOL! Now THAT is the magic question. Actually, If it were able to oscillate you could use TWO rods! Think linkages, also, you could use it to make intermittent unidirectional movement like a servo. YOu could use brakeline cables to transfer motion to articulate a hand to open and close. Things like that. Just thinking outside the box. Mostly to make a return motion where gravity wouldn't work or rods would collide if the shaft kept going.


well, rather than having 2 rods connected at two different places, mount them both at the same place where they'll never cross over each other's mounting point (think FCG). if you wanted psudo-asyncronous motion, you'll probably need a gear or two anyways, so there wouldnt be an interference fit there either


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## randyaz

Nice circuit Otaku.

I came up with this configuration last year for precise positioning of the wiper motor in forward and reverse and speed control in eiter direction to move a prop's arms and for lowering/raising a large spider. It uses a Parallax HB25 ($49) motor controller for handling speed and direction and a QTI sensor ($6) for shaft loctation. I used a Stamp2 for the microcontoller and a Prop1 or Prop2 will work too. The size is 2"x2" and it handles up to 16v and 25 amps and uses PWM so the motor doesnt loose torque.

Its a little pricey but gives complete control of wiper motor. I did a write up here:
http://spooksterville.com/site/index.php?option=com_content&task=view&id=16&Itemid=25


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## Dr Morbius

Oh yea, I remember that..pretty neat!


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## BuriedAlive

Awesome job on the controller, Otaku, and for adding yet another great use for wiper motors.


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## Otaku

Here's the parts list and circuit schematic. If anyone has questions, just let me know.

http://halloweengallery.com/displayimage.php?pos=-3799

http://halloweengallery.com/displayimage.php?pos=-3800

For some reason the circuit drawing doesn't display in the window, but if you click on "show full size image", you'll be able to see it. I'll get pics of the opto reflector and the 10 amp outboard relay later this week. I also had to add a couple of wires/connectors for the 10 amp relay that allows you to switch the motor power. These are not on the parts list, but I'll post all the info you need. You'll notice the ?'s on the parts list - the .doc to .gif conversion didn't know what to do with the omega signs.


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## Otaku

I'm posting a PDF of the opto mounting bar and reflector. They're very easy to make. Let me know if you have any questions.


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## Otaku

Here's a PDF of the outboard 12VDC 10A relay that's used to switch the 5VDC power to the motor. The two blue wires connect between the power supply, relay and motor. The 10A relay is powered by the 12VDC output of the circuit As always, let me know if there are any questions.


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## Koumajutsu

Otaku: ever considered trying this using an optointerupter hacked out of an older (non optical) mouse and a circle piece of cardstock or thin rigid opaque plastic with a notch cut in it?


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## Dr Morbius

Koumajutsu said:


> Otaku: ever considered trying this using an optointerupter hacked out of an older (non optical) mouse and a circle piece of cardstock or thin rigid opaque plastic with a notch cut in it?


This is making me think of output...using the mouse's optointerupter for motion capture..my brain hurts now.


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## Koumajutsu

well, the optointerupter is really nothing more than a very short infrared trip beam. a PC mouse uses a couple to count pulses to determine how far you move the mouse and which direction you move. it then relays x and y change serialy down the bus, either pci or usb. (if looking to do some serious mouse hacking, I suggest using a PS2 mouse, or using a USB to PS2 adapter because the ps2 signal structure is still rs232 compliant and can be adapted to a comm port for input to a PC )


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## Otaku

Koumajutsu said:


> Otaku: ever considered trying this using an optointerupter hacked out of an older (non optical) mouse and a circle piece of cardstock or thin rigid opaque plastic with a notch cut in it?


Actually, I hadn't thought of using a mouse. The idea originally was for an effective replacement for compressed air that didn't need a PC to watch it. I had already designed a very similar circuit for some custom fixturing at work, so adding a few features was fairly easy. I did learn how much I didn't know about LM555's, though! Anyway, you're right, all the hardware is there inside a PS2 - you'd just need to add a way for the optics to see what the shaft is doing.


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## Koumajutsu

well, i thought of the optics from the mouse in a way as removing them from the mouse completely, the device should work in your circuit the same way but without having to bend and cut a metal flange for the "eye" to see. I was thinking of those less mechanicaly inclined.

Dr M got me thinking of how far one could go with making use of the guts of a mouse, so i got a little carried away


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## Otaku

Ahhh, I see! You're right, you would want to gut the mouse, of course. The opto that's used in my circuit does need a pretty good-sized reflector and that presented some challenges in mounting it on the motor. I'm still not convinced it's in the right place. I may try a different mounting scheme that can be done with off-the-shelf hardware.


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## Dr Morbius

Koumajutsu said:


> well, i thought of the optiocs from the mouse in a way as removing them from the mouse completely, the device should work in your circuit the same way but without having to bend and cut a metal flange for the "eye" to see. I was thinking of those less mechanicaly inclined.
> 
> Dr M got me thinking of how far one could go with making use of the guts of a mouse, so i got a little carried away


I'm bad that way...heheh. But yea, a mouse has some pretty interesting things in it, although I've never opened up an optical mouse, I wonder how one of those could be hacked? I have no idea how one works though...although that would be a discussion for another thread. I doubt it would pertain to Otakus wiper motor circuit though.


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## Otaku

One other factor that contributed to the size of the reflector is the amount of overrun of the motor after power is cut. A smaller reflector (or any sensing device that depends on feeding back a location to the controlling circuitry) would pass the opto's field of view before stopping. This would then activate the power relay and the motor would continue to rotate. When the motor is in actual use and there is a load on the shaft, this issue may disappear because the rotation would be braked. Once I get the system in a coffin I'll have a better idea of this behavior.


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## Koumajutsu

not to mention the delay induced by the relays. Could they be replaced with a couple FET's?


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## Otaku

Sure. The on-board relays are both 5VDC 2A, so FETs could replace them, as well as the 12VDC 10A DPDT that switches the motor power. The 10A ice cube relay is likely the slowest part of the system.


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## Phil

Two power relays to the motor would allow polarity reversal if the change of direction was desired.


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## Koumajutsu

Phil said:


> Two power relays to the motor would allow polarity reversal if the change of direction was desired.


a single DPDT relay can provide polarity reversal if you're dead set on relay control


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## Phil

true, but I gotta do something with this box of SPDT relays!


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## halstaff

Do you have an updated video link of this in operation?


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## toozie21

halstaff said:


> Do you have an updated video link of this in operation?


I know it is a old thread, but it is new to me as well. Would love to see some more info on it as well!


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## Otaku

Let me take a look on an old drive and see if I can find some useful info. Were you looking for something specific? The circuit has been re-designed to use a limit switch rather than the opto-sensor for indexing the motor (too unreliable), and the updated boards should still be available from Jeff at Simple Circuit Boards.


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## halstaff

I'm working on an upcoming article on triggers and sensors for Servo Magazine and will be mentioning limit switches. This thread came to mind and was just hoping that the video was still available for those looking for more info.


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## toozie21

Otaku said:


> Let me take a look on an old drive and see if I can find some useful info. Were you looking for something specific? The circuit has been re-designed to use a limit switch rather than the opto-sensor for indexing the motor (too unreliable), and the updated boards should still be available from Jeff at Simple Circuit Boards.


Hmmm, I don't see it on his site, do you have a link to it?


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## Otaku

I think you'd need to email him and ask for the Otaku motor controller board. Jeff hasn't updated his site for a while.


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## Otaku

halstaff said:


> I'm working on an upcoming article on triggers and sensors for Servo Magazine and will be mentioning limit switches. This thread came to mind and was just hoping that the video was still available for those looking for more info.


There's a series of videos in this thread:
http://www.hauntforum.com/showthread.php?t=11632&highlight=buried+alive
It doesn't really show the motor with the limit switch attached or the latest board rev. More of a showcase thread.


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## Otaku

Steve, this one might be more useful. Click on the title bar to play the file.
http://vid73.photobucket.com/albums/i231/Otaku1031/Wipermotordemo.mp4


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