We swapped a $250 sensor for a $5 one. That is not a compromise. That is the point.
Traditional myoelectric prosthetics use EMG — electrical signals from muscles, captured by electrodes on the skin. The technology works, but it is expensive, sensitive to sweat and fatigue, and requires specialist calibration. We use Force Sensitive Resistors instead. They detect pressure. They cost under $5 each. They do not care about sweat. And if one breaks, you replace it.
Sensing
FSRs sit inside the socket liner, pressed against the residual limb. When a muscle contracts, pressure changes. That change is the signal. No electrodes. No amplifiers. No calibration session with a specialist. Just pressure.
Control
Two actuators. One drives independent thumb movement. The other curls all four fingers together through a single tendon. That gives you a pinch grip, a power grip, and a wrap — which covers most of what hands actually do in a day. Pressure maps to grip speed and force. The harder you press, the stronger the grip.
Repairability
Every component was chosen with one question in mind: can this be fixed in Gisenyi? Standard fasteners. No proprietary parts. No firmware that requires a laptop and a license to update. 3D-printable structural components. If something breaks two years from now, somewhere far from a clinic, it gets fixed.
The number that drives every decision
Target BOM for a complete Myogen system
A commercial myoelectric hand costs $15,000 to $100,000. Ours will cost under $250. That is not because we cut corners — it is because we made different choices. Fewer actuators. Cheaper sensors. Open-source platform. Local assembly. Every decision is measured against that number, because if we miss it, the whole point falls apart.