An optical tachometerTachCraft
An optical tachometer for the workshop. Stick a strip of tape on anything that spins, point your phone camera at it and read the speed in RPM. TachCraft staggers the timing of its pictures, so fast parts read true instead of showing a false slow speed, and a torch strobe lets you check the reading by eye.
The camera tach and strobe are free. A one-time Pro unlock adds sound and vibration tachs, saved readings and workshop tools.
What it does
- Camera tach: tape a mark, point the camera, read RPM
- Staggered frame timing so fast parts are not misread as slow ones
- Finds the mark by itself, or tap where it passes
- A plus or minus figure, a "sure" bar and the mark's pulse over one turn
- Torch strobe with fine steps, turns per flash and a torch timing check
- Pro: sound tach for fans, motors and drills, no mark needed
- Pro: vibration tach, resting the phone on a running machine
- Pro: run stats, target band, saved readings as CSV, surface speed and pulley tools
- Works offline, no account, nothing recorded or uploaded
Articles
Questions
Where can I get it?
TachCraft is out now on Google Play for Android phones and tablets.
How can a phone camera measure fast parts?
A camera takes about 30 pictures a second, which normally makes faster parts look slow or backwards (the wagon wheel effect). On phones with manual camera control, TachCraft staggers the timing of its pictures and keeps the shutter short, so only the true speed fits. It shows the fastest speed the current shutter can follow, about 18,000 RPM at 1/2000 s.
Do I need to mark the part?
For the camera tach, yes: one strip of white or shiny tape works best. The Pro sound and vibration tachs need no mark.
What does the strobe do?
It flashes the phone torch so a mark seems to stand still, which lets you check a reading by eye. Phone torches top out at about 25 flashes a second, so faster parts are frozen every few turns. TachCraft measures how steady your torch is and shows a flashing light warning first.
What does Pro add?
A one-time unlock adds the sound tach, the vibration tach, run stats with a target band, saved readings you can share as CSV, and workshop tools for surface speed, wheel speed and pulley ratios. The camera tach and strobe are free.
Does it record or upload anything?
No. Camera pictures, sound and motion are analysed on the phone as they arrive and then discarded. There is no account.
Get TachCraft
Free to download on Google Play. Questions? Email us