Workbench

Date

Written by

Workbench

Qmotor

Date

Originally published

March 28, 2023

Some boards need power! For our next feature focus, we decided to stress test Quilter’s ability to design boards that need higher currents. For our first take, we decided to implement a stepper motor driver.

This board is based on the Arduino Motor Shield Rev3. This board is a shield that can be used with an Arduino Uno and can two DC motors or a single stepper motor.

This board is designed to handle up to about 4A of total current. For the design, we assigned a 4A ampacity to all high power traces. Quilter automatically assigns a minimum 52mil width to all traces to support the current.

Component side of the assembled Qmotor motor-driver shield, with an L298 chip and pin headers.
Reverse side of the Qmotor shield with a large white Quilter logo and soldered header connections.

Our input files are here and our our output design file is here.

The script we used to drive the motor is here.

We coupled this shield with our Quilter-designed Arduino Uno. We tested the board with a simple stepper motor, which pulls 0.8A steady state. Checking for hot spots, we just see significant heat from the L298 (which is expected to reach over 100C in heavy use). Otherwise, no other hot spots were found.

Thermal image of the Qmotor board and connected stepper motor, with the hottest visible area on the board.

We are excited to start Quilter’s journey into high power design! What should we build next?

Qmotor motor-driver shield connected by wires to a stepper motor.

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Validating the Design

With cleanup complete, the final question is whether the hardware works. Power-on is where most electrical mistakes reveal themselves, and it’s the moment engineers are both nervous and excited about.

Continue to Part 4

Cleaning Up the Design

Autonomous layout produces a complete, DRC'd design; cleanup is a brief precision pass to finalize it for fabrication.

Continue to Part 3

Compiling the Design

Once the design is prepared, the next step is handing it off to Quilter. In traditional workflows, this is where an engineer meets with a layout specialist to clarify intent. Quilter replaces that meeting with circuit comprehension: you upload the project, review how constraints are interpreted, and submit the job.

Continue to Part 2