Privacy policy

Stillspin Strobe Tachometer · Revised 15 September 2026

In short

Readings you save stay in one file on your iPhone. Camera and microphone frames are analysed as they arrive and never kept. The only file made from the camera is a freeze clip you chose to record, and it is deleted when you leave that screen. Nothing reaches the developer.

Who is responsible

Aleksei Bukhalov makes the app and is the person responsible for it under data-protection law: alex@bukhalov.com. He receives none of what is described below. It stays on your iPhone unless you send it yourself, and then it goes only to whoever you send it to.

Readings you save

When you keep a measurement, the app stores its rate, the method that took it, the marks per turn in force, the name and notes you gave it, and any target speed you typed. Target speeds you add on the Saved screen are stored the same way. All of it sits in a single file inside the app's own storage. The app also keeps your display unit, flash brightness and length, the haptics switch, and the results of the emitter check, in the iPhone's settings storage for this app.

Camera, microphone and the freeze clip

The optical instrument and the turntable screen read the rear camera, the acoustic instrument reads the microphone, and recording a freeze uses the camera that faces the same way as the flash. iOS asks before either is first used; refusing one leaves the other methods working, and the Open Settings button on a refused screen takes you to the iPhone's Settings if you change your mind. Frames and audio taken for a measurement are analysed in memory and then discarded.

Recording a freeze writes an eight-second video, with no sound track, to temporary storage so the system share sheet can pass it on. The app deletes it, and the raw capture behind it, when you leave the Record the freeze screen. Until the unlock is bought the app never asks for the microphone, and asks for the camera only when you record a freeze.

Sharing and exporting

Exporting measurements hands their text directly to the share sheet without writing a file. Sending a freeze clip hands the video to the same sheet, together with a short message that names the app and links to its App Store page; you can edit or delete that message before sending. Where either goes is your choice, and once it arrives it is outside the app's control. Choosing Save Video makes iOS ask permission to add that one clip to your photo library; the app never reads the library.

The unlock and the App Store

The single in-app purchase is handled by the App Store. Apple takes the payment and keeps the record of it against your Apple Account. The app asks StoreKit on the device whether that record exists, both when it starts and when you tap Restore purchase, and stores no receipt, account identifier or payment detail. Refunds are handled by Apple.

Code the app does not contain

There is no advertising, attribution, analytics or tracking code, and no crash reporting service of the developer's. There is no sync between devices, no web version, no shared database and no account. The app does not ask for or read your location. Its only network traffic is StoreKit.

Deleting everything

Swipe to delete any saved reading or target on the Saved screen. A deleted reading comes back if you tap Undo before leaving that screen; otherwise it is gone. Deleting the app removes its file and its settings. Backups made by iOS may keep copies according to your own settings — see Apple's explanation of iCloud Backup. The developer holds no copy and cannot recover anything for you.

How long anything is kept

Saved readings and targets stay until you delete them or delete the app. Settings stay until the app is deleted. The raw recording and the finished clip are removed when you leave the Record the freeze screen, whether or not you sent the clip.

Your rights

The GDPR and the UK GDPR give you the right to ask what personal data is held about you and to have it corrected or erased, and the California Consumer Privacy Act gives you the right to know what is collected and to refuse its sale. The developer holds nothing about you to show, correct or erase, and sells or shares nothing. What the app keeps is on your iPhone, where you can see it on the Saved screen and delete it yourself. You can still write to the address below, and you can complain to the data-protection authority where you live.

Flashing light and younger users

The app is a measuring instrument for machinery, made for adults rather than children. It flashes rapidly, which can trigger a seizure in people with photosensitive epilepsy; it shows a warning before it will run, and asks again when Dim Flashing Lights is switched on.

Who to write to

Aleksei Bukhalov makes this app. Questions about this policy go to alex@bukhalov.com, with Stillspin in the subject line.

Revisions

When this policy is revised, the date above changes, and the copy compiled into the app is revised in the same release.