CAN Motor PCB

What’s here?

Presented here:

• Guide for manufacturing the OpenExo CAN Motor PCB

• Design files 

• Voltage divider for battery voltage sensing (see below)

This PCB is designed to work with the CubeMars AK-series of motors, which communicate with the PCB via CAN. This PCB is also capable of communicating with other CAN motors, but support for such motors has not yet been integrated into the codebase. If you would like to use other CAN-based motors, refer to our software documentation for information on how to incorporate them into the firmware. 

If you’re following the build guide exactly, this PCB is the one you will use. The other PCB (Maxon PCB) is intended to broaden the capabilities of the OpenExo platform, though no transmission approaches or end-effectors have been designed for these motors. Stay tuned for future updates regarding these motors.

Voltage divider for battery voltage sensing

Starting with AK Board 0.5.1 Mark III, the INA219 chip was replaced with a voltage divider for estimating the battery voltage. To enable this feature:

1. Source two resistors, R1 and R2.

2. Measure and record their resistance before installing them on the PCB.

3. Install R1 and R2 on the PCB.

4. Update the values of RESISTOR_1 and RESISTOR_2 in config.h to reflect the measured values.

5. Set the battery sensor type to 3 in config.h.

6. Change the “volt_sense” pin in Board.h from “not_connected_pin” to “27”.

7. Reprogram the Teensy.

The following equation determines the maximum allowable battery voltage: 3.3 * (R1 + R2) / R2.

Note: We recommend starting with resistor values of 47 kiloohms for R1 and 4.7 kiloohms for R2, which result in a maximum allowable voltage of 36.3 volts.

Continue to OpenExo PCB Guide 

Continue to CAN Motor PCB Files 

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