Project Overview
Client: Tobias Grove – FFDEV
Project: Compact ESP32-Based Modular PCB with Breakaway Tabs
Designed a cost-efficient, modular single-sided PCB with breakaway tabs to support multiple configurations using the ESP32 microcontroller. The board integrates sensors, analog front-ends, power management, and user input interfaces, optimized for flexibility, manufacturability, and low BOM cost.
Problem Description
The client required a compact, low-cost, and modular PCB with support for multiple variants. It needed to:
Support always-on and detachable HX711 modules
Be powered and charged via USB-C for LiPo batteries
Support I²S MEMS microphone, MPR121 capacitive touch sensors, and expandable I²C and GPIO access
Maintain minimal size while ensuring robust analog and digital signal separation
Be suitable for hand-soldering in key areas, and easy for batch production
Solutions Implemented
✅ Designed a 2-layer single-sided PCB with carefully routed analog/digital signals
✅ Integrated ESP32-WROOM module with BLE and solder pad for optional Wi-Fi antenna
✅ Added USB-C charging circuit using TP4056 with reverse-polarity protection and PTC fuse
✅ Created detachable HX711 boards using mouse-bite breakaway tabs
✅ Implemented low-noise layout techniques (separate ground/power planes, stitched GND vias)
✅ Included reset/boot buttons, PWM output, and user input switches
✅ Designed for expandability: I²C headers, solder pads for MPR121, digital pots, and microphone
✅ Verified SPI/I²C conflicts, ensured reliable boot behavior (strapping pin isolation)
✅ Optimized component placement for usability (connectors near edge) and manufacturability
Impact on the Project
🔹 Enabled the client to test multiple hardware configurations without needing new PCBs
🔹 Reduced board re-spins and BOM cost with reusable modular design
🔹 Improved analog signal reliability with proper grounding and layout
🔹 Addressed critical power-on reset and bootloader issues early in development
🔹 Delivered a clean, production-ready PCB layout that is easy to assemble and test
Hardware Designs and Schematics (Multiple Variations)
V2.5 – 4 Layer Board
V2.3 – Smaller Version with 2 Layer Board
