Jester,
Based on my own experiences over 50 years ago your "wiper motor park signal" is actually a simple "keep it going until the wipers are at parked position". This position is usually adjustable.
The signal will alternate on/off every revolution of the output shaft. Typically this internal switch is used to provide motor power if the user has turned off the wipers before they've reached the parked position. The park switch then opens and the motor stops.
Yes, my first car did not have self parking wipers so I added a cam and a switch to do the business.
Be aware that these motors have a substantial start current surge which could impact on the Pi if the power source isn't butch enough. As above consider adding noise suppression capacitors across the motor connections and motor ground.
Edit: the switch is likely to be a simple wiper system that provides an On - connected, Off - open circuit. The On could also be joined to motor ground consistent with vehicle wiper motor wiring. The chassis/ground of the motor either needs connecting to Pi O volts and the GPIO input uses a pull-up to 3.3 volts. BUT ensure there is no 12 volts on the switch contacts. As outlined above better use an Opto-isolator system to sense these types of signals.
Based on my own experiences over 50 years ago your "wiper motor park signal" is actually a simple "keep it going until the wipers are at parked position". This position is usually adjustable.
The signal will alternate on/off every revolution of the output shaft. Typically this internal switch is used to provide motor power if the user has turned off the wipers before they've reached the parked position. The park switch then opens and the motor stops.
Yes, my first car did not have self parking wipers so I added a cam and a switch to do the business.
Be aware that these motors have a substantial start current surge which could impact on the Pi if the power source isn't butch enough. As above consider adding noise suppression capacitors across the motor connections and motor ground.
Edit: the switch is likely to be a simple wiper system that provides an On - connected, Off - open circuit. The On could also be joined to motor ground consistent with vehicle wiper motor wiring. The chassis/ground of the motor either needs connecting to Pi O volts and the GPIO input uses a pull-up to 3.3 volts. BUT ensure there is no 12 volts on the switch contacts. As outlined above better use an Opto-isolator system to sense these types of signals.
Statistics: Posted by RaspISteve — Wed Jul 31, 2024 10:54 am