Stack-chan SG90 Desktop Robot for M5Stack Core2

Stack-chan is a palm-sized companion robot. An M5Stack Core2 shows an animated face, and two small SG90 servos let it look left, right, up and down. It runs JavaScript firmware, so you can add your own behaviours, connect it to chat or voice services, or drive it from a browser over Bluetooth.

Updated for modern use: it uses the SG90 case designed for the Core2 with its M5GO Bottom2, so you do not need a custom circuit board or to take the M5Stack apart. Every part comes from regular shops.

What you build

• A printed shell that holds the Core2 and its bottom module
• Feet that carry the pan servo
• A bracket that holds the pan and tilt servos (SG90 version, plus an MG90S version)
• A spacer and optional hats, including cat ears

Files

• Print-ready STL files for the shell, feet, both brackets, the spacer and two hats
• STEP files for the shell, feet and SG90 bracket so you can change the design
• Build guide PDF: printing, firmware setup, servo pins, assembly and troubleshooting
• Bill of Material PDF with quantities, notes and a shop link for every part

Print settings

Print in PLA at 0.2 mm layers. Lay the shell with the M5Stack opening facing down and use supports. The feet and bracket print without supports.

Electronics

• M5Stack Core2 with M5GO Bottom2 (or a Core2 for AWS, which already has it)
• Two SG90-size 180 degree servos (the M5Stack Servo Kit 180 has two, plus two Grove to Servo adapters)

Bill of Material

Every part you need to buy, with quantities, notes and shop links, is in the Bill of Material PDF in the files of this model.

Software

Build and flash the Stack-chan firmware with the Moddable SDK using the Core2 + SG90 target. Set the pan and tilt servo pins to match the two Grove ports you used (the build guide shows how). Then use the Stack-chan browser tools to change Wi-Fi and preferences, try MODs, or make your own face.

Full build guide and source

The build guide, source and all project files: https://github.com/ToolKnox/hawkridge-stack-chan-sg90-m5stack-core2-robot (Code > Download ZIP).

Safety

SG90 servos draw a short burst of current when they start; if the Core2 resets, charge the battery fully. Some servos sold as SG90 or MG90S differ in size or horn shape, so check yours against the bracket before printing many copies.