Home coffee roasting doesn’t have to mean expensive commercial machines or sealed, black-box electronics. In the book Build Your Own Coffee Roaster with Raspberry Pi, author Matthew Beard explains how to build a fully functional DIY coffee roaster using readily available parts, a Raspberry Pi, and a control system designed specifically for real roasting work.
 
 

The Cobra Smart Roaster

A DIY coffee roaster built from standard parts

The project, called Cobra, is built around a heat gun, solid-state relays, infrared temperature sensing, and a Raspberry Pi running a Linux-based control system. These components form a compact, affordable DIY coffee roaster that can automatically follow roasting profiles, while still leaving the builder in full control of both hardware and software.

OpenRoasterController: software without subscriptions

Rather than relying on proprietary software or subscriptions, the roaster uses the OpenRoasterController (ORC), a free control system created by the author and built around Node-RED. ORC runs directly on the Raspberry Pi and manages the roasting process based on temperature measurements.

Recipes can be created for specific coffees, allowing roast parameters to be selected with a single click. Fixed profiles make it possible to define drying, browning, and development phases precisely, while manual mode allows direct user control during a roast.
 

The ORC HMI


Profiles and Artisan integration

The book also explains how to connect ORC to Artisan Scope using MODBUS. This allows temperature data to be displayed and recorded in Artisan, making it possible to compare roasts, mark roast phases, and overlay live roasts with saved profiles.

Hands-on electronics with an emphasis on safety

The build process is described step by step, covering power supply setup, low- and high-voltage wiring, solid-state relay installation, Raspberry Pi connections, infrared sensor mounting, enclosure layout, and system testing.

Electrical safety, grounding, heat management, and proper component spacing are treated as core parts of the project. The explanations are practical and based on the author’s own build experience.


More than a coffee roaster

Setup for roasting in a bowl with a whisk
 

While the Cobra can be built for around $120 (depending on existing tools and parts), the book makes clear that cost is only part of the motivation. The project is also about learning: understanding control systems, experimenting with profiles, and seeing how software and hardware interact in a real, physical process.

Build Your Own Coffee Roaster with Raspberry Pi will appeal to coffee enthusiasts, makers, and electronics hobbyists who enjoy building things themselves — and who prefer knowing how their machines work, rather than trusting a closed box.

By the end of the book, readers will have a working DIY coffee roaster and a clear understanding of how its control system operates, making it suitable for further experimentation or customization.

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