Here's a simple use of the SmartBoard Baseboard, configured to drive an external H-Bridge, which itself it wired to a motor. This could be used as a starting point for another project, or as a life-test for a motorized system. The H-Bridge is driven from a PWM signal, where initially the PWM duty cycle is hard-coded. In a later version of the software, the duty cycle would be based on the system voltage driving the H-Bridge.

Circuits Involved

• Analog Input - 1 channel to measure the system voltage. Requires appropriate resistor divider circuit to achieve appropriate scaling.
• PWM Output - 2 channels of PWM output, one for each phase of the external H-Bridge driver.
• USB - Since all the high power is external, the unit can be powered strictly from the PC USB port.
• USB Serial Communications - It's always handy to see something happening, so the current status will be available on the serial port accessed by the PC.

Block Diagram

Here's the basic block diagram.

                    ------- USB to PC
                   /
  +-------------+-[]-+-------------+
  |             |    |             |
  |             |    |             |
  |             |    |             |
  |             |    |             |
  |             |    |             |
  |             |    |             |
  |   [12345678]+----+ [123456]    |
  +--------------------------------+
       |     |          ||
  System     Ground     |+-- Phase B
  Voltage               +--- Phase A