© 2025 The Johns Hopkins University Applied Physics Laboratory LLC
DCMini is a miniaturized biopotential amplifier and multi-sensor system designed for research applications in brain-computer interfaces (BCI), muscular interfaces, and closed-loop biofeedback. It combines a flexible set of sensors with powerful wireless telemetry and SD logging — in a package you can stick on your head.
⚠️ This hardware is for research and development only. It is not certified for medical use and must not be used for medical diagnostic purposes.
- ✅ In active development and research use
- 🧪 Not for clinical or medical use
- 🔬 Used in closed-loop neuroscience, BCI, and sensor fusion prototyping
- 📦 3D-printable case design in progress
- 4–16 Channels of EEG/EMG/biopotential via ADS1299 (DC-coupled)
- nRF52840 BLE + USB radio module
- nPM1300 PMIC for LiPo charging + monitoring
- USB ground loop isolation for noise-free wired telemetry
- ICM-45605 6-axis IMU (accel + gyro)
- APDS-9253 ambient light & IR sensor
- PDM Microphone (SPK0838HT4H)
- DRV2605 + LRA haptics support
- MicroSD removable storage
- WS2812B Neopixel
- NFC tag interface for quick BLE pairing
- Board-to-board & FPC connectors for expansion and frontend access
- 5V boost rail to power external modules
- Open-source KiCad design with custom footprints
This is an advanced DIY PCB project. Many components on this board do not have leads for hand soldering, and you will at least need a hot-air rework station to place those. Additionally, this project is almost entirely built on flex PCBs, which have their own set of challenges, particularly getting them to sit flat on a hot plate. Many efforts were made to keep components to just one side of the board, but there are some connectors that just have to be on the rear of the board and some of these connectors are fine-pitch and very challenging to hand solder.
You can find a storefront where you can purchase an assembled board HERE. Maybe someday you'll be able to purchase a fully-constructed DCMini HERE.
- docs/assembly.md: PCB assembly documentation
- docs/build.md: Case print/mechanical build instructions
- docs/firmware.md: Instructions for flashing firmware
- docs/software.md: Documentation for companion software and acquisiton APIs
- docs/bci.md: Tutorial for using the DCMini as a brain-computer-interface
- docs/sleep.md: Information for using the DCMini for sleep studies.
DCMini includes:
- nPM1300 battery management (charge + monitor)
- 5V boost converter for peripherals
- USB isolation for noise-sensitive data capture and safe wired operation
| Interface | Connector | Notes |
|---|---|---|
| EXT: Expansion | DF40C-60DP (0.4mm pitch) | Exposes digital interface |
| AFE: Analog Frontend | DF40C-60DP (0.4mm pitch) | Exposes analog interface |
| FPC: Analog Frontend | FH35C-45S (0.3mm pitch) | Exposes analog interface + I2C |
Our rust firmware stack is available at the following address: https://github.com/dcmini-org/dcmini-fw
This hardware is licensed under the CERN Open Hardware License v2 – Permissive.
- ✅ You can use, modify, make, and sell this hardware
- ✅ You can incorporate it into commercial projects
- 🧾 If you distribute modified versions, include the original license and note your changes
- ❌ Don't use "CERN", "JHUAPL" or contributor names for marketing without permission
- 🩹 This project comes with no warranties — it’s experimental
See LICENSE.txt for full details.
This work was supported in part by intramural research funding from Johns Hopkins University Applied Physics Lab (JHU APL).
- Griffin Milsap: Hardware design
- Preston Peranich: Firmware implementation
- Will Coon: Device validation
If you use this hardware in a project or publication, we’d love to hear about it! Additionally, please consider citing:
Coon, W. G., Peranich, P., & Milsap, G. (2025). StARS DCM: A Sleep Stage-Decoding Forehead EEG Patch for Real-time Modulation of Sleep Physiology. arXiv preprint arXiv:2506.03442.