Wiper Motor question

[jssherrard]

I am using a wiper motor powered through an HB-25 on my Prop-1. Is it possible to use the parking switch terminals on the wiper motor to inform the Prop-1 when the motor is in its "parked" position? If so, how? Thanks!

[livinlowe]

You might want to put a meter on the terminals to see if they simple short together ( a switch inside the motor) or if you get 12v out. Other than this, if you don't have the data sheet on the wiper motor, I'm not sure how else you could tell.

[JonnyMac]

If it is a dry-contact output then you can connect it between Px.R and Px.W (where Px is the pin of your choice; if P6 or P7 move the SETUP jumper to DN). 

If the output is hot I wouldn't use it as the power going to the motor from the HB-25 is modulated and you may not be able to read that very reliably.  If you were not using a speed control then you could insert a 22K resistor between the [hot] output and a Px.W pin to read the switch.

[jssherrard]

The switch plate is connected to the ground; however, I can easily remove the ground from the switch plate without affecting the motor itself. Wouldn't this make it a normally closed dry-contact output?

I have to apologize... I have been assuming folks are familiar with the inner workings of these motors. I am using a MonsterGuts 12vdc Wiper Motor. The switch plate in my motor is connected to two unused terminals and the ground. As the motor tuns the switch plate turns. There is a notch in the switch plate which opens the connection once per revolution. If I remove the ground the switch plate will be effectively isolated from the electronics of the motor.

Is this what you mean by "dry-contact"?

Here is an image showing a very similar motor:



There is virtually no difference between my motor and the motor image above. The parking switch terminals (P1 and P2 in the image) are not connected to anything other than the switch plate. If I understand correctly I should be able to connect the parking switch terminals to Px.R and Px.W once the ground is disconnected from the switch plate...

Right?

(I feel kinda in over my head here, but I truly want to learn...)

[JonnyMac]

"Dry contact" means there is no current flowing through the connection unless you put it there externally.  Since you say that P1 and P2 are not connected to anything else that would be a "dry" connection and you should be able to use it like a normal switch.

[jssherrard]

Thanks to Jon & livinlowe for the feedback!

I disconnected the ground from the switch plate, connected the HB-25 to PIN0, connected the parking switch to PIN1 and...

IT WORKS PERFECTLY!!!

;D

This setup allows me to precisely sync my prop and audio, knowing that I can program the wiper motor to begin & end each "show mode" sequence at a precise position in the motors rotation. I am truly grateful for your assistance!