Bosch Seat Motor Wiring Help

This is our team’s first year using a Bosch seat motor on the robot, and we are unsure of how to solder the resistors onto the am-3812 circuit board. Any help would be greatly appreciated; the more instructions the better!

Biggest issues are not getting solder bridges on the transistors and getting the resistors installed in the correct locations. Documentation is very difficult to find. Seat to DIO Assembly Pictures (am-3812).pdf (1.1 MB)

See the attached (hopefully it did attach) .pdf file for resistor positions.

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Thank you very much this is exactly what we needed!

Used to be a direct link to that document. I see it is no longer even in the general folder that is linked. I can check with AM to correct.

Agreed on the difficulty in avoiding solder bridges. Just use a fine tip solder iron and someone with steady hands.

@Tobor3758, suggest you test the board after soldering with an oscilloscope to see if you get a square wave output that drops from around 4V to pretty close to zero. If there’s any bridging you might get some sporadic results.

Does the am-3812 kit come in the KOP? We can’t seem to find it. It is currently out of stock with AndyMark. Are there any other alternatives for wiring the this motor (Bosch Seat Motor)?

If I understand it correctly, the am-3812 circuit board is for the wiring of feedback from the motor to the RoboRio. If all you need to do is power the motor to turn and you don’t need the feedback to your software, I don’t think the am-3812 is needed. We’re using this Bosch motor for the first time this year also, and will run the power through a Talon with limit switches but hadn’t planned on wiring up the H+ and H- wires. I’m sure someone will chime in if I’m wrong about this, and I thank them in advance!

We were planning to wire similar to how we did our motors for our wheels. So directly to the power distribution since it is 12v and then the signal cables to the Roborio PWM ports for programming.

…I don’t think the am-3812 is needed…

correct. It’s only to convert the hall sensor output to a digital read format for directly connecting to the Roborio digital ports.

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Please be careful not to bog down (mechanically overload) this or other auto window or seat motors. Note that its Specification Sheet off http://wpilib.screenstepslive.com/s/4485/m/63630/l/679357-bosch-seat-motor says “Note: Motor is protected with a thermal switch.” If you overheat the motor it’ll turn off until it cools, and all you can do is wait. And R35 says we can’t mess with the motor’s internals.

And yes, we learned about this the hard way.:blush:

I don’t believe this is in the KOP, we are having the same problem with the part being out of stock. Did you ever find another vendor?

My team is in Canada so I am not sure how quickly you can get it but I found this:

Thanks for the find. We couldn’t find a substitution. It isn’t available in the USA with Studica. Would you all be able to purchase an extra so we can be for shipping and the cost via paypal to our team in the USA?

If you have trouble finding It’s pretty easy to make with common components. Here’s some help…

Possibly just solder to a prototype board like this and cut what you don’t use…

  1. AM has been in and out of stock a couple times, but seems to re-supply quickly. So, signup there for email alerts.

  2. We wired a custom solution using the online schematic. We did have the electrical engineer helping and checking it out at his work. I’m not sure whether they made modifications to the circuit, but initially did. On testing, we had two problems. First, was the students wired the inputs backwards. Second, was interference (getting way to many counts). Finally, since the hall effect doesn’t have a direction you have to develop a different way to count up and down, we used the polarity of the voltage from the VictorSPX. We tried the control signal sign at first, which made for a weird PID output. But now my bucket is getting turned within a few degrees tolerance :smile:.

  3. I have two on order from AM. I’ll check when they get here, but since it will be surplus I might be able to spare one. I’m not sure when the shipment will arrive. I’m in Kansas, so from then it would be a day or two, I’m guessing. Just looked up the order and still is pending, so I can’t really say how long it would take. But is an option, if you don’t get it solved another way.

edit: I forget to say to solve our interference problem we used a ferrite bead on the signal wire (iirc).

^^ this circuit is easy enough to wire up with a scrap of perfboard if you are fair or better at soldering. Use sandpaper or at least fingernails on the component leads to get them shiny.

We did have slight changes in the circuit, see below:

With the 3906 transistor

Sorry we are still waiting for it ourselves we aren’t sure when it’s going to come.

I think the Andymark schematic may be different than the printed circuit board.

I think the 5.6k is actually connected to the input (not 220 ohm) and the 220 ohm is connected to the emitter of the first stage BJT.

Note: It’s kind of an odd design anyways. More typically the emitter would be tied to 5V. Also, the schematic is drawn reverse. Would have been better if the H+ and H- were on the left side of the page.

FYI, the schematic will only work if you use NPN transistors instead of what’s drawn… Working on a writeup.

I remember using a multimeter to reverse engineer against the PCB and left thinking the schematic was just wrong - that is, it didn’t match the board they actually sold :blush:. This explained why we got different results when we tried to replicate the circuit using our own parts on a breadboard.

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