Two small Bluetooth boxes built for the Microdyno app. Both count every ignition pulse with a microsecond timestamp. One also heats a wideband probe and delivers the air-fuel ratio live.
Neither sensor is available to order yet. Shop status
Two wires to the AC output of the ignition. The sensor turns every wave into a clean pulse, timestamps it to the microsecond and sends it to the app over Bluetooth. The rpm is live on the phone, no microphone, no recording, no post-processing.
The sensor runs on a battery and looks after its own power: five minutes without an ignition pulse and without an app connection, and it goes to sleep. The next ignition pulse or a press of the button wakes it. You never have to switch it off.
If Bluetooth drops during the ride, nothing is lost: the sensor also stores every pulse itself, and the app fetches the missing pieces after the run.
| Measures | Ignition pulses, microsecond timestamps |
|---|---|
| Wiring | 2 wires to the ignition's AC, after the voltage regulator |
| Input | Optocoupler, galvanically isolated, TVS protection |
| Pulses per rev | 1 to 24, set in the app |
| Power | Battery, USB-C charging |
| Standby | Deep sleep after 5 min, wakes on ignition pulse or button |
| Radio | Bluetooth LE, one connection at a time |
| Storage | Pulse log in the sensor, fetched by the app |
| Firmware | Updates over Bluetooth from the app |
| App | Microdyno for iOS and Android, Apple Watch |
The same rpm input, plus a wideband controller for a Bosch LSU 4.9 probe. The box runs off a 12 V battery, heats the probe and sends AFR, lambda and probe state to the app together with the rpm.
The heater is the delicate part: a cold exhaust is wet inside, and water on the hot ceramic destroys the probe. So the box stays in standby after power-up and only heats once the engine has run for 30 seconds. When you stop the engine the heater stays on for another five minutes, so a short stop doesn't mean waiting again.
In the app you see AFR live for jetting and, after the run, as an overlay on the power curve. The Apple Watch shows AFR straight from the sensor, on your wrist: if the mixture drifts from the optimum at full throttle, a badly set carburettor, an air leak or a blockage shows up at once, before the engine takes damage.
| Measures | Rpm like MicroDyno-RPM, plus lambda and AFR |
|---|---|
| Probe | Bosch LSU 4.9 wideband, 6-pin connector |
| Wiring | Red/black to 12 V battery, 2 wires to AC, probe |
| Probe heater | Starts after 30 s of engine running, 5 min after-run, then standby |
| States | Standby, Heating, Adjusting, Measuring, error states |
| Values | AFR, lambda, probe temperature, board voltage, 10 times a second |
| Power | 12 V, heater up to 2 A while warming up |
| Radio | Bluetooth LE, one connection at a time |
| Firmware | Updates over Bluetooth from the app |
No trimming, no harmonics editor. Press stop, the curve is there. Over three runs in a row that makes the difference.
Wind, traffic, a second scooter next to you: a problem for the microphone, not for the sensor. It counts ignition pulses, not sounds.
The lambda variant shows whether the engine runs rich or lean, live while riding and later in the curve. The microphone can't do that.