COSMIIC Biopotential Amplifier (BP2)

The BP2 is a dual-channel biopotential recording module for acquiring myoelectric signals (EMG/MES) from voluntary muscles. It captures differential signals from epimysial or intramuscular electrodes, processes them on-board, and places the results on the CANopen network for use by other modules (e.g., to trigger stimulation patterns).

How it works

The BP2's Atmel AT90CAN128 processor manages signal acquisition from two differential electrode pairs (1 cm contact spacing). Raw signals are amplified, filtered, and digitized. The processor performs feature extraction (RMS, threshold detection) and broadcasts processed data over CANopen PDOs for real-time closed-loop control.

Designed for extremity placement near the target muscles, minimizing lead length and maximizing signal quality.

Hardware

Signal Processing

The BP2 supports multiple recording modes accessible via the NNP-API:

• Raw mode (enterTestRaw) — stream raw myoelectric signals
• Feature extraction mode (enterTestFeatures) — on-board RMS/threshold processing
• Patient mode (enterPatient) — closed-loop EMG-triggered stimulation

MATLAB Control

nnp.networkOn;
nnp.setBPGains(node, ch1_gain, ch2_gain);  % set bandpass filter gains
nnp.enterTestRaw(node, ch);                 % raw EMG streaming
emgRecordRaw(nnp);                          % GUI for EMG visualization

Design source

This page publishes the Fusion 360 Electronics molecule for the BP2 (BP2 FRAME MOL). Fusion Electronics is EAGLE underneath, so the board and schematic ship as EAGLE-format .brd/.sch, which the Adom viewers render natively — the interactive schematic, PCB and 3D shown on this page (and in Adom Nucleus) all come from this Fusion export.

• Upstream hardware: COSMIIC-Community/Implantables-BP2-Hardware (Apr 2025)
• Firmware: COSMIIC-Community/Implantables-BP2-App (C, AVR toolchain)
• License: open source under CERN-OHL-P-2.0 (hardware) and MIT (firmware).

Files

Created by: COSMIIC · Fusion 360 Electronics export