How to create a circuit that will take place of Bosch Seat Motor DIO Kit (am-3812)?

I need to build a circuit that will regulate the encoder’s Low signal(it’s too high for RoboRIO), it should be compatible for RoboRIO. But while doing this, I should hold the HIGH(5V) signal below RoboRIO’s HIGH min input voltage limit. Normally, the DIO Kit does all of these; but I should create a circuit instead of it. Please help me about how can I do this.


https://wpilib.screenstepslive.com/s/currentCS/m/kop/l/679357-bosch-seat-motor

http://files.andymark.com/PDFs/Bosch+Seat+Motor+DIO+Kit+(am-3812)+Signal+Information.pdf

But truthfully, I think it was more trouble than it was worth. If you can place an external encoder, you’ll have an easier time setting it up for controlling it. The internal sensor is a hall effect sensor that does not give you the direction the motor is turning. You have to infer that in some other manner. We successfully used the voltage feedback from our motor controller, but you might need a Talon (I don’t recall) to do that.

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I’m in the process of writing up a deep dive on this motor… Just about everything on it seems to be wrong! Yes, I got it to work and tested it on three motors. FYI, out of three random motors from our stash, I got one that already had a dead sensor!

Key tips:

  1. If you reverse the polarity you WILL fry the sensor! Yes, the GREEN wire is the positive lead!
  2. It is a hall sensor looking at a magnet ring. It only counts motor rotations, not directions. I’m still working on the part number, waiting for a call back from Allegro.
  3. The AndyMark board is a level shifter that lowers the voltage generated by the 220 Ohm resistor by two diode drops. This brings “low” into the no-mans land of digital logic and leaves “high” in actual guaranteed high range. Thus, the circuit sort of works sometimes…
  4. The AndyMark schematic does not match what the board is supposed to do; those are actually NPN transistors, not PNP as claimed. If you put in PNP it won’t work at all.
  5. You MUST keep track of what direction you are driving the motor when you collect counts. I suggest not looking for counts unless you are driving it.

I’ll publish the details once I get all the ducks in a row. Message me if you need the schematic sooner.

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Micah and I have designed a board for this job. I’m trying to source a board mount connector to prevent the dreaded “hooked it up backward” problem…

If anyone knows the actual connector series that would be a HUGE help. I believe its a Sumitomo, but the part number doesn’t come up on their site.

Hey sir, I need a schematic and the bom about the design can you help me?

Often, the connector is designed to some industry standard format and a compatible connector can be more easily sourced from a different manufacturer. In all my years, I have used some obscure connectors but I have never heard of connectors from Sumitomo.

I assume you want to use these motors on your bot? I can send you the schematic when I get back to Houston Tuesday/Wednesday.
I hope you know that this is NOT an encoder… it’s just pulses per rev. You have to get direction from the voltage you are applying :wink:

Here you go! The intention is to drive Q1 into saturation but not fry it when the Hall sensor is in the low current state, and get it to turn off when the Hall sensor is in the high current state. It would be -really- nice if we could come up with a mating PCB mount connector, but you can solder the standard connector to your board. Color code on the connector is SUPER critical. Reversing the Voltage on that stupid Hall sensor will fry it! I know, its weird that an automotive sensor is vulnerable to such things, but that’s been my experience! I never did manage to actually get a data sheet for the sensor either; just one that was sorta close and acted pretty much the same way.

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