In short. We developed the electronics and firmware for a portable, rechargeable, Bluetooth-controlled stimulator for facial muscle re-education and prevention of disuse atrophy. The system has three parts: the stimulator module, a mobile app that sets rhythm and intensity, and disposable pre-gelled Y-shaped electrodes that attach magnetically. The client’s device received FDA clearance.
The challenge
On a stimulator the disposable electrode is the product and the electronics support it. The pad sets the load the output stage sees, the comfort that decides whether patients keep using the therapy, and the recurring revenue. A 2026 study reports moderate to high pain in more than 20% of NMES participants even with a gel pad intervention, and a 2024 study notes contact dermatitis in about 40% of TENS users.
What the electronics should do
Design against an aged pad
A fresh pad and the same pad after eight applications present very different impedance. Constant voltage lets the dose fade; constant current drives voltage into a drying gel. The output stage has to be specified against end-of-life impedance.
Measure the electrode in the device
Measuring impedance every session lets the device derate, warn or refuse, and turns a comfort complaint into logged data the clinician can use.
Ramp in firmware
Ramp intensity rather than stepping it, and hold the ramp profile in firmware so it can change after human factors testing without new hardware.
Get the magnets right
Patients with facial weakness often have impaired dexterity. The magnetic retention force has to sit above the hydrogel peel force and below what an impaired hand can remove, measured on production pads.
The economics run through the same part
| Electrode case at 100,000 units | Cost per pad |
|---|---|
| Lean OEM | $0.18 to $0.24 |
| Typical commercial | $0.26 to $0.32 |
| Premium reusable | $0.35 to $0.45 |
| Conductive hydrogel inside the pad | $0.05 to $0.14 |
| Retail benchmark | $0.57 to $0.75 |
Full engineering note: The consumable is the product: electronics for an FDA-cleared wearable stimulator.
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Sources
- The consumable is the product: electronics for an FDA-cleared wearable stimulator
- OVA Solutions project portfolio, 2026
Client names are not disclosed. Updated on October 9, 2026.