How to Control a DC Motor with an Epson Optical Encoder and Pololu Driver Using Arduino

Question:

In your YouTube video about programming Arduino with an Epson optical encoder and DC motor for a DIY DTG printer, how do you program the system so that the motor moves in response to the encoder using a Pololu driver?

Answer:

Wiring & Programming the Encoder + Pololu Driver on Arduino

To make your DC motor move in response to an Epson optical encoder, you'll need to set up an interrupt-driven feedback system and use a motor driver like the Pololu to control power and direction. This setup is very similar to what’s used in CNC systems and DIY DTG printers for precise motion control.

Here’s how to do it step-by-step:

1. Hardware Wiring

Optical Encoder:

• Connect VCC (usually 5V) and GND to the Arduino’s 5V and GND pins.

• Connect Encoder A output to an interrupt-capable pin on the Arduino (typically D2 or D3).

• Optionally, connect the Encoder B output if you want to track direction (for quadrature encoding).

DC Motor + Pololu Driver:

• Connect the motor terminals to the Pololu driver’s output.

• Connect the driver's PWM and DIR input pins to available digital/PWM-capable pins on the Arduino.

• Provide sufficient external power (e.g., 12V or 24V) to the motor and motor driver according to the motor’s rating.

2. Arduino Code Overview

You’ll want to:

• Read the encoder using either a library like Encoder.h or attachInterrupt().

• Track position or velocity by counting encoder ticks.

• Use a control loop, often a PID controller, to drive the motor based on encoder feedback.

Example Code Sketch:

Notes on Implementation:

• The Pololu driver handles the motor current and switching, but you must manage PWM direction and power via software.

• This example uses position-based PID, but you can also modify it for velocity control by computing ticks per unit time.

• If you're using Epson optical encoders from printers, make sure you check the pinout (they’re usually labeled A, B, VCC, GND).

Helpful Resources:

• Encoder Reading: PJRC Encoder Library

• Motor Driver Reference: Pololu Product Pages

• PID Tuning: Try different Kp, Ki, and Kd values to stabilize motor motion and avoid oscillation.

Repair Support for Printer-Driven Projects

Controlling motors and encoders is an advanced part of DIY printer builds, and hands-on configuration is critical. For that reason, we’re unable to provide remote or live support for motion control projects. That said, we do offer in-person repair and diagnostic services through our workshop:
Printer Repair Service
(https://bchtechnologies.com/printer-repair-service)

Keep in mind we operate on a first-come, first-served basis, and turnaround time may vary. We also encourage DIY builders like yourself to continue exploring through online resources. Our YouTube channel homepage (https://youtube.com/@bchtechnologies) is a great place to start. Use the search icon next to the "About" tab to look up keywords like "DTG Arduino motor control" or "optical encoder."

There’s a growing community of makers doing the same kind of projects, and you might find others sharing similar wiring diagrams or code tweaks.

Thanks again for your thoughtful question and for being part of our creative tech community. We hope your DIY DTG build turns out excellent—and that your motor control works as smoothly as you envisioned!