Engine RPM 4+

Acoustic Tachometer

Real-Time Specialties

    • $8.99

iPhone Screenshots

Description

Measure the RPM of an engine by analyzing the sound it makes. Engine RPM listens to the sound of a running engine and uses advanced signal processing algorithms to extract the frequency of that sound and calculate the RPM.

This app is primarily for setup and diagnostics of engines. After setting the the number of cylinders and whether the engine is a 2-stroke or 4-stroke engine, the app can work with any internal combustion engine, from diesel tractors to aircraft engines to motorcycles to chainsaws. To use the app you must set an expected RPM range to guide the analysis algorithms to the correct RPM. A real-time graph of the autocorrelation graph is displayed to help in troubleshooting and adjusting the expected RPM range.

The analysis requires a clear sound from the engine without excessive interference from extraneous sounds. Do not expect to read the RPM of an engine while other things are making too much noise at the same time. The analysis also requires that the RPM be stable. It cannot read the RPM of an engine that is rapidly accelerating. For this reason, and because of the need for adjusting the expected RPM range, this app should not be considered a drop-in replacement for an operational tachometer.

Setup options include update periods from 93 milliseconds to 1.5 seconds, one to 12 cylinders, 2-stroke or 4-stroke, low-pass filtering, and signal clipping. The overall RPM range is 400 to 90,000 RPM (although at any one time, the operational range is typically +/- 30% around a nominal expected RPM). Precision is usually about +/- 10 RPM.

What’s New

Version 2.5

* Optional Low-Pass Filtering to suppress high frequency interfering sounds.
* Optional signal rectification to transform high frequency percussive bursts into low frequencies that were otherwise too low to be detected by the microphone.
* Older unreliable modes of operation were removed (auto ranging and tracking) in favor of the more reliable Hint Band mode.
* Built-in help is greatly expanded.

Ratings and Reviews

3.8 out of 5
26 Ratings

26 Ratings

EJTVDY ,

Expensive and complicated but it works....

1- Read all the help pages beforehand; it’ll take you about 5-10 minutes but well worth it.
2- I used to set idle on a 2 stroke fuel injected motorcycle where the idle is critical: too high and the bike runs too lean, too low and it bogs down in low RPM starts.
3- At first I had it set up to sample every 3 seconds. That was too long. So I cut to 3/4 of a second and it was less of a hassle. I was able to guesstimate the current RPM’s at 1500, (actual was closer to 1700), so I set up the software that way, kept making small adjustments on idle screw until
I got it just right.
4- Logging the RPMs and times was a nice feature.
5- to get a 5 star price needs to come down materially or ease of use must improve significantly.

Overall I’m happy with this given the alternatives.

Rein’s Small Engine ,

Great concept. Great execution. Great price!

The Tiny Tach tachometer I’ve been using in my small engine work wasn’t extremely expensive, but it’s finicky and difficult to use when I’m tuning something like a chainsaw.
This app, after a couple minutes glossing over the instructions, was almost intuitive to get to function. It will be really nice to be able to set this down and have both hands free to operate the throttle and adjust carburetor settings on equipment now. Large, easy to see display and controls plus other features I haven’t even gotten to will make my work SO much easier! Thanks guys, for all your hard work. I’m totally happy with the price!

blade1693 ,

Pricey but works good.

This was a little more expensive that I would have liked but once I used it I would say it’s defiantly useful. Used it to check low and high speed of my lawnmowers and it’s right on. Just slide around the hint rpm as it’s running and it finds the speed right away. It’s also cool that you can also see the audio waveform. The app doesn’t look to fancy but as long as it keeps working with future iOS updates I’ll be happy.

App Privacy

The developer, Real-Time Specialties, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More

Supports

  • Family Sharing

    Up to six family members can use this app with Family Sharing enabled.

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