Bric(k)-o-lage – DCM Brick

Recently I finished a first version of the DCM Brick (DC Motor Control).  As for the DIO brick and the Master Brick, I designed schematic and PCB using fritzing . Also I ordered the PCBs from fritzing FAB. For the firmware I used my own libemb as a basis.

The DCM brick allows driving two DC motors independently.  Each motors direction (clockwise and counter-clockwise) is controlled by a PWM to allow adjustment of the speed. For driving the motors, I used the SN754410 quadruple half-H driver from TI. It turned out, that this choice was not the best since the SN754410 if specified to need at least 4.5 to operate while the MSP430G2553 operates from 2.8-3.6V. It turned out that the H  bridge works (most of the time) relay-able if driven with 3.6V but I think I need to switch to something like the TI DRV8835.

For the case I tried to design some kind of snap-in-lock (as one could see in the pictures below). The cover uses to standoffs which snap into the bottom half of the case. The result is fairly OK, and I expect it to become better when printing the case in higher quality (did only quick prints so far).

DCM with Connected DC Motor

DCM with Connected DC Motor

DCM Brick Specifications

  • Uses a MSP430G2553 from TI
  • Runs custom firmware
  • Connects to master brick through I2C
  • Control 2 DC motors in direction and speed using the SN754410
    QUADRUPLE HALF-H DRIVER
  • 2 status LEDs
  • Serial RX/TX for debugging

DCM Brick Schematic / PCB

The full files could found here.

DCM Brick Schematic

DCM Brick Schematic

DCM Brick PCB Top

DCM Brick PCB Top

DCM Brick PCB Bottom

DCM Brick PCB Bottom

Some pictures of the PCB (with and without parts):

DCM PCB Bottom/Top

DCM PCB Bottom/Top

DCM PCB Top/Bottom

DCM PCB Top/Bottom

DCM PCB

DCM PCB

 

DCM Brick Case

Find the OpenSCAD and STL sources here.

DCM Case Exploded

DCM Case Exploded

DCM Case

DCM Case

The following pictures show a first print out (done in „poor but fast“ printing quality):

DCM Case Closed

DCM Case Closed

DCM Case Open

DCM Case Open

DCM Case Inner/Outer View

DCM Case Inner/Outer View

DCM Case Outer/Inner View

DCM Case Outer/Inner View

DCM Brick Firmware

The whole firmware sources are located here.

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