Microdyno

Stefan Hurzlmeier

About this app

Microdyno measures the power and torque of your motorcycle or scooter with your phone. From the rpm trace of an acceleration run in a chosen gear, the app calculates the curve the way a chassis dyno does, only on the road.

Three ways to get the rpm
• Microphone: The app reads the rpm from the engine note. In the spectrogram editor you see the fundamental and its harmonics and erase any noise that gets in the way.
• Microdyno rpm sensor: A small Bluetooth sensor on the ignition lead reports every spark. No noise, no steps, the most accurate curve.
• Lambda sensor: Wideband probe with the AFR trace over rpm. Live while riding as a floating window (Picture in Picture), and in the analysis with map and audio playback.

Analysis
• Power, torque, rpm and speed as curves, peak values at a glance
• Trim the run at the markers, remove outliers, smoothing in three levels or, in expert mode, as a freely combinable chain
• Correction to DIN 70020 or SAE with temperature, pressure and humidity, fetched from the weather service on request
• Compare runs, with a mean curve over several runs
• Vehicles with gearbox, ratios, tyres, weight and driving resistances. Over 100 templates from the Vespa smallframe to the motorcycle

Cloud and browser
• Sign in with Apple, Google or e-mail and your recordings, results and vehicles stay in sync across your devices
• Web app at app.microdyno.de: open, trim and analyse recordings in the browser, download the files
• Without signing in, everything stays on the device

How it works
1. Create a vehicle or pick a template
2. Mount the phone, connect the sensor or use the microphone
3. Start recording and accelerate through the chosen gear
4. Trim the run, save the result, compare

Who it is for
Vespa and scooter riders, motorcycle tinkerers, tuners and workshops. Anyone who wants to know what an exhaust, a carburettor setting or a new cylinder really does.

Accuracy
The calculation is checked against dyno measurements. Repeatable results need equal conditions: same gear, same stretch of road, warm engine. Absolute figures depend on the weight and driving resistances you enter. For before-and-after comparisons on the same vehicle that does not matter.

No subscription, no hidden costs. The app is under continuous development. Questions and requests to [e-mail].

What’s new

• Microphone analysis far more accurate: rpm located between FFT bins, no more 162 rpm steps. Power curve right at start, end and peak.
• Open audio recordings in the web app (app.microdyno.de): the spectrogram is uploaded with the recording, also for old ones.
• One trim screen for phone and web, working on the spectrogram. Faster opening, trimming without recomputation.
• Spectrogram view without frame and time axis.