Last updated: 4 September 2026
Deutsch · English
In short: Without an account, all measurement data stays on your device. There are no analytics or tracking services, no advertising and no selling of data. If you choose to create an account, your vehicles, recordings and results are stored with Google Firebase in the Frankfurt data centre so you can use them on several devices and in the browser. You can delete your account and all cloud data yourself at any time in the app or in the browser.
This policy explains how personal data is processed when you use the Microdyno app for iOS and Android, the web app at app.microdyno.de, the website microdyno.de and the Microdyno sensor. In case of discrepancies between the German and the English version, the German version prevails.
Stefan Hurzlmeier, Benediktusweg 13, 93049 Regensburg, Germany
E-mail: support@microdyno.de
No data protection officer has been appointed, as the legal requirements for a mandatory appointment are not met.
The app works fully without an account. The following data is then processed and stored only on your device and is not transmitted to us.
The Microdyno sensor sends ignition pulse timestamps and the RPM derived from them over Bluetooth Low Energy; the lambda variant additionally sends the air-fuel ratio, the state of the lambda probe and the board voltage. The Bluetooth permission is required for this. The data is stored on the device as a recording.
If you grant the location permission, the app records speed, latitude and longitude about once per second during a recording. Speed, gear ratio and the engaged gear are derived from it. These positions become part of the recording. The approximate coordinates are also used once to fetch weather data (see section 4.1). Without the location permission recordings still work, without speed and gear detection.
To determine RPM from the engine sound the app can record audio. This only happens when you start an audio recording. Recordings are stored and analysed on the device.
Vehicle name, weight, gear ratio, frontal area, drag coefficient, tyre size, measurement results (power, torque, curves), ambient conditions and the names you assign. You enter this data yourself; it relates to your vehicle and, without an account, is stored only on the device.
The legal basis is Art. 6(1)(b) GDPR (providing the functions you request). You grant the Bluetooth, location and microphone permissions in the operating system and can revoke them there at any time. The data remains stored until you delete it in the app or uninstall the app. Recordings and results can be exported as CSV or audio files; what you share afterwards is your responsibility.
For sync and the web app you can sign in with Sign in with Apple or Google. Sign-in runs through Firebase Authentication (Google). We process the identifier at the sign-in provider, your e-mail address (with Apple optionally an anonymised relay address), your name on first sign-in where provided, a user ID assigned by Firebase, sign-in timestamps and technical session tokens. Apple and Google are independent controllers for their sign-in services; their privacy policies apply (Apple, Google).
Anything you delete on one device or in the browser is removed from the cloud and from your other devices as well.
We use Firebase, a service of Google Ireland Limited, Gordon House, Barrow Street, Dublin 4, Ireland, as a processor under Art. 28 GDPR (Firebase Authentication, Cloud Firestore, Cloud Storage, Cloud Functions, Firebase Hosting), based on the Google Cloud Data Processing Addendum. Database and files are stored in the region europe-west3 (Frankfurt am Main). For Firebase Authentication, Google may also process sign-in data on servers in the USA. This transfer is based on the European Commission's adequacy decision for the EU-US Data Privacy Framework, under which Google LLC is certified, and additionally on the EU Standard Contractual Clauses.
The purpose is providing sync and the web app, which you request by creating an account. The legal basis is Art. 6(1)(b) GDPR. Use is voluntary; the app is fully usable without an account.
Only your account can access your cloud data; this is enforced technically by the service's access rules. As operator, the controller has technical access and uses it only to fix faults or at your request in support.
Cloud data is kept until you delete it. "Delete account" in the app or the browser deletes your account, all database content and all files immediately and permanently; the data on your device remains. Under Google's deletion process, data may remain in the provider's backups for up to 180 days before being overwritten.
For the climate correction of power figures, the app fetches temperature, air pressure and humidity for your approximate location when you request it. The coordinates and your IP address are transmitted to the weather service: OpenWeather Ltd., London, United Kingdom (privacy policy), or Open-Meteo (privacy policy). An adequacy decision of the European Commission exists for the United Kingdom. The legal basis is Art. 6(1)(b) GDPR. You can enter the values by hand instead.
At your request the app checks microdyno.de for new sensor firmware and downloads it if available. The hosting provider processes the access data described in section 5.1.
Both are served through Firebase Hosting (Google Ireland Limited, see 3.3). On every request the hosting provider processes technically necessary access data: IP address, date and time, requested file, transferred volume, referrer, browser and operating system. The purposes are delivery, security and fault analysis; the legal basis is Art. 6(1)(f) GDPR. Access data is stored by the provider for a short time and not merged with other data.
The web app uses the sign-in from section 3.1 and stores in the browser (Local Storage, IndexedDB) only what is technically necessary for the session and your settings (§ 25(2) no. 2 TDDDG). No cookies or similar techniques are used for advertising or analytics.
The website and the web app load fonts from Google Fonts (Google Ireland Limited). Your IP address is transmitted to Google in the process. The purpose is a consistent appearance; the legal basis is Art. 6(1)(f) GDPR. More information: Google privacy policy.
If you write to us by e-mail, we process your details to handle the request (Art. 6(1)(b) and (f) GDPR). Our mailbox is operated by IONOS SE, Elgendorfer Straße 57, 56410 Montabaur, Germany, as a processor. Requests are deleted once handled unless statutory retention obligations apply.
Data is not passed on to any other third party unless we are legally obliged to.
You have the right of access (Art. 15 GDPR), rectification (Art. 16), erasure (Art. 17), restriction of processing (Art. 18) and data portability (Art. 20). You can export recordings and results yourself at any time and delete your account with all cloud data yourself. Consent can be withdrawn at any time with effect for the future (Art. 7(3)).
Right to object (Art. 21 GDPR): Where we process data on the basis of Art. 6(1)(f) GDPR, you may object at any time on grounds relating to your particular situation. We will then no longer process the data unless we can demonstrate compelling legitimate grounds that override your interests.
To exercise your rights, an e-mail to support@microdyno.de is enough. You also have the right to lodge a complaint with a supervisory authority (Art. 77 GDPR). The authority responsible for us is the Bavarian State Office for Data Protection Supervision (Bayerisches Landesamt für Datenschutzaufsicht), Promenade 18, 91522 Ansbach, Germany, www.lda.bayern.de.
There is no automated decision-making including profiling within the meaning of Art. 22 GDPR. Your data is not used for advertising or sold.
The service is not directed at children under 16. We do not knowingly process children's data. If you are a parent or guardian and learn that a child has created an account, write to us and we will delete it.
All transfers are TLS-encrypted. Cloud data is protected by account-bound access rules and stored in Frankfurt. On the device, the protection mechanisms of your operating system apply.
We update this policy when the processing or the legal situation changes. The current version is always available at microdyno.de; we point out material changes in the app.