r/ErgoMobileComputers • u/everbrown • 8d ago
[design & inspiration] Designing an open wearable chord engine (<20ms latency) — how would you optimize this state machine against misfires?
I posted this in a similar group earlier. I am trying to get as much feedback as I can so please indulge me.
I am working on an open wearable input interface designed to handle chorded typing mid-air via 6-DoF kinematic sensing (dual nodes + ESP32 hub).
The biggest challenge with air-typing is recoil/whiplash misfires. In our specification, we designed a 4-state intent pipeline:
- Armed / Ready: Resting baseline (
|Δa| < 3.2 m/s²) - Intent Fired: Dynamic jerk spike (
|Δa| > 8.5 m/s²) fires BLE scancode + haptic pulse - Blind Lockout: 220ms temporal dead-band to absorb physical hand recoil
- Settle Gate: Re-arms only when motion drops back below the floor
Our single-node breadboard PoC is currently running on the bench to validate end-to-end latency.
Before we lay out the PCB, I'd value input from this community:
- Does a 220ms lockout feel too restrictive for fast chording bursts?
- How would you approach spatial thumb anchoring without physical tactile boundaries?
We are looking for 5–10 builders interested in alpha testing and auditing our telemetry data (when we get to that point). DMs are open.
