Discover how to make a micro motor pololu housing LEGO-compatible with 3D printing to use it in your robot designs.
The housing for the micro motor pololu has been designed with OpenScad using a LEGO-compatible library:
Download the STL file and print it.
Suggested printing parameters:
Layer height (mm): 0.3
Wall thickness (mm): 0.8
Upper and bottom part thickness (mm): 4.2 (very important, otherwise the top cylinders break easily)
Printing speed (mm/s): 30
Without sticky platform
All necessary components are:
- A DRV8838 driver.
- Pololu micro-motor (torque/speed ratio depends on application).
- Two wires of different colors.
- Pin male connector 2.54mm pitch.
- Printed top of the part housing.
- 3D printed housing.
The connection of the motor driver with the microcontroller can be done as shown in the following figure:
You can see that the engine is controlled by two signals: ENABLE and PHASE, enabling rotation and controlling the sense of rotation and speed of rotation (with PWM), respectively, as shown in the table provided by the manufacturer. The motor has a braking mode in which ENABLE = 0 and a high impedance mode (motor disconnected, but without brake) if the ENABLE signal is on the air:
We have soldered the wires of the signals that we need to three 2-pin connectors each, as shown in the following figure:
Secondly, we have put the driver and the engine by the holes and soldered the wires of the motor to the terminals of the driver as shown in the following figure:
Finally you just need to attach the wheel, as shown in the figure:
We could also use a cross axle bush connector of Lego Technic (Element ID 4206482). In this case, we use a thermo-sealing gun by inserting the material hot glue inside the bush and followed by the motor shaft:
By doing this, we have a compatible a motor that we can use in any Lego design with proper adaptation.