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Topic: DC ENCODED MOTOR FROM AUTOMOTIVE CONNECTION (Read 145 times) previous topic - next topic


Feb 16, 2020, 10:45 pm Last Edit: Feb 16, 2020, 10:47 pm by leonedevenezia
I removed from a tailgate of a BMW X5 the  actuators.
The motor of actuator runs with 12 V DC and has an encoder that takes advantage of the hall effect.
With the oscilloscope I'm able to read the square wave on the blue and green wires (chan A e chan B).
Two hall sensors are used in the motor encoder to read the direction and rotation speed of the motor.
The sensors are marked 12L (I suppose they are 12L Melexis Board Mount Hall Effect / Magnetic Sensors). The circuit is powered at 5Vdc.
Outputs A and B come from the GND pin of the 12L component.
The outputs A and B are connected with the GND of the power supply (5V) with by a resistor I used a 220 OHM one, with the oscilloscope I'm able to see 2 squares waves.
With the Voltmeter when I turn the motor I read V = 3.74 as low signal and V = 4.68 as hight signal for each output A and B (hall sensor not excited and hall sensor excited)

Can I read the status of the encoder with these two voltage levels ?
I can connect A and B to arduino digital I / O .

I have doubts about how to make the connection.
Can you suggest me how to make the connection?


I am taking a guess but years ago they use to use quadrature detection, very similar to digital mechanical pots. Give that a try.  This response is to help you get started in solving your problem, not solve it for you.
Good Luck & Have Fun!
This response is to help you get started in solving your problem, not solve it for you.
Good Luck & Have Fun!


Feb 17, 2020, 04:49 am Last Edit: Feb 17, 2020, 04:53 am by groundFungus
I do not know that particular encoder but usually the outputs are from the pulled up out pins.   They will be close to ground and close to 5V as the encoder is rotated so can be read by digital inputs.

What are the voltages on the A and B encoder out pins referenced to ground when the motor is rotated (without the resistors from the ground pins to ground)?
You will save everyone's time if you read and follow the forum guidelines.  :)          

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