AD5941 EC Sensor Toolkit
Portable 4-channel electrochemical sensor based on AD5941 + ESP32-C6
Architecture note: This page describes the earlier AD5941/ESP32-C6 toolkit. The current STK RevM20 hardware case study uses continuous discrete TIAs, an ADS131M04, DAC80508 and ESP32-S3. The historical measurements below do not qualify RevM20 performance.
I am building this instrument myself, working from the published literature on AD5941-based portable potentiostats.
What
A palm-sized, BLE-enabled, 4-channel electrochemical sensor toolkit (STK) built around the Analog Devices AD5941 analog front-end and the ESP32-C6 MCU. Supports cyclic voltammetry (CV), chronoamperometry (CA), electrochemical impedance spectroscopy (EIS), and open-circuit potentiometry (OCP).
Hardware highlights
- AD5941 analog front-end with internal TIA, DAC, and 16-bit ADC
- ESP32-C6 for BLE + Wi-Fi telemetry
- External LTC6078 bypass to AIN3 — a workaround for the AD5941 internal LPTIA latch-up failure mode observed after ~30 s of sustained current (software mitigation alone is insufficient)
- Custom KiCad layout, optimized BOM, and reduced-footprint stretchable PCB variant in development
Firmware status
| Mode | Status |
|---|---|
| Cyclic voltammetry | Phase 1 complete (clean duck-shape on standard ferrocyanide, dEp limited by carbon electrode) |
| Amperometry | In progress (current focus, May 2026) |
| OCP / ISE (Na⁺) | Next milestone |
| EIS | Validated against benchtop potentiostat |
DIY screen-printed electrodes
A parallel track produces in-house SPEs from SEBS substrates with Dycotec DM-CAP-2100S carbon ink — a low-cost alternative to commercial DRP-110 chips, with the same standard 3-electrode geometry (WE / RE / CE).