Engine RPM vs Strobe Light
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Engine RPM
Analyze engine sound to calculate RPM using advanced signal processing. Ideal for engine setup and diagnostics, it supports various engine types and provides real-time feedback for accurate readings.
- Acoustic RPM measurement
- Engine sound analysis
- Supports 2-stroke/4-stroke engines
- Configurable cylinder count
- Real-time autocorrelation graph
- Adjustable update periods
- Low-pass filtering
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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.
Strobe Light
This application transforms your smartphone into a digital tachometer using its flashlight. It measures the rotational speed (RPM) of objects by flashing light at them, making them appear stationary when the flash rate matches their speed. Save readings and use it for mechanics, education, or industrial checks.
- Measures RPM of rotating objects
- Adjustable strobe speed (1-10,000 RPM)
- Quick adjustment buttons (+/- increments)
- Flash sync for accuracy
- Save and review RPM data
- Works in low light conditions
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Strobe Light - RPM turns your phone into a powerful tool for measuring the speed of rotating objects. The app works like a digital tachometer and offers two measurement modes: Strobe Light and Camera. You can measure the RPM of fans, motors, wheels, and other rotating devices without touching them. In both modes, the same stroboscopic principle is used. When the flash rate or camera frame rate matches the speed of the object, it creates the illusion that the object is standing still. This helps you visually determine the exact rotational speed of the object with high accuracy. Strobe Light Mode Using your phone's flashlight, this mode flashes light at the object in a specific pattern. It works best in a dark or low-light environment and is ideal when you want a quick RPM reading with the built-in flashlight. How to Use (Strobe Light): Mark the rotating object with something visible (a sticker or tape works well). Point your phone's flashlight toward the object. Turn on the strobe using the power button. Adjust the strobe speed using the + and - buttons until the object looks still. The RPM shown on the screen is the object's rotation speed. You can save the reading for later reference. Camera Mode Camera mode uses your phone's camera to show a live preview at a set frame rate (FPM — Frames Per Minute). When the frame rate matches the object's RPM, the rotating object appears frozen on screen. This mode is useful in well-lit conditions when you want to see the object clearly while tuning the speed. How to Use (Camera): Open Camera mode from the home screen and allow camera permission. Point the camera at the rotating object. Adjust the frame rate using the + and - buttons until the object looks still. The value shown on the screen is the object's RPM. Use the flash button if you need extra light in darker areas. Save or reset your reading anytime from the bottom buttons. Where It's Useful: Mechanics: Test fans, engines, or motors by measuring RPM. Education: Ideal for physics experiments that require RPM measurements. Industrial Use: Check the condition of rotating machinery. Calibration: Ensure rotating devices are running at the correct speed. Maintenance: Compare readings over time using saved history. Key Features: Two Measurement Modes: Choose Strobe Light or Camera from the home screen based on your environment and preference. Adjustable Strobe Speed: Set the strobe from 1 to 10,000 RPM for accurate measurements. Camera Frame Rate Control: Set camera preview from 30 to 14,400 FPM for precise visual tuning. Quick Adjustment Buttons: Easily change the speed with buttons for +1, +10, +50, or +100 RPM increments in both modes. Flash Sync (Strobe Light): Ensures the light flashes at the correct frequency for accurate RPM readings. Built-in Camera Flash (Camera Mode): Toggle the flash on or off for better visibility in low light. Save and Reset: Save current RPM readings with a custom title or reset to default anytime. History Tracking: Save and review your RPM data anytime for easy access from the menu. Works in Different Lighting: Strobe Light works best in the dark; Camera mode works well in normal and low-light conditions. Simple and Energy-Efficient: The app's interface is easy to use and designed to be practical for everyday measurements. Visual Tachometer: Acts just like a real tachometer using visual strobe techniques with your phone's flashlight or camera. Strobe Light - RPM makes it simple to measure RPM without any special tools or equipment. Whether you prefer the classic flashlight strobe method or the new live camera preview, this app gives you flexible and accurate RPM measurement in one place. Perfect for mechanics, hobbyists, students, and professionals alike. Contact us at: zsmapps2024@gmail.com Terms of use: Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Screenshots
Verdict
The clearest difference is review sentiment: Engine RPM at 48% against Strobe Light's 0%. Engine RPM also leads on rating (4.0 vs 2.0) and in-app purchases (none vs 2). Strobe Light's advantage is price (Free vs $8.99) and update cadence (every 7 months vs every 16 months). On device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Strobe Light is free to download; Engine RPM costs $8.99 up front. Strobe Light sells 2 in-app purchases, starting at $5.99 per month. Engine RPM asks for nothing beyond the download.
Engine RPM holds the better App Store score, 4.0 against 2.0. That said, the two scores are not equally well evidenced: Engine RPM has 35 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 48% of Engine RPM's written reviews are positive against 0% of Strobe Light's.
Engine RPM ships an update every 16 months, Strobe Light every 7 months. The most recent releases landed on November 6, 2026 and October 31, 2026 respectively.
| Parameter | Engine RPM | Strobe Light |
|---|---|---|
| Price | $8.99 | Free — better |
| Rating | 4.0 (35 ratings) — better | 2.0 (1 ratings) |
| Positive reviews | 47.7% of reviews — better | 0.0% of reviews |
| Number of ratings | 35 — better | 1 |
| Update frequency | Every 16 months | Every 7 months — better |
| Ads | No — better | Yes |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Ad-supported |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 13.0 — better | 15.0 |
| Further details — not scored | ||
| Size | 3 MB | 25 MB |
| Age rating | 4+ | 4+ |
| Developer | Real-Time Specialties | Zain Saeed Mughal |
Customer experience
Engine RPM
Strobe Light
Bugs and requests
Engine RPM
Reported bugs
12 issues- Does not register live RPM readings
- Displays incorrect or random numbers
- App opens then closes immediately
- Blank display or flashes incorrect data intermittently
- Cannot get consistent readings
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- Does not work on specific devices (e.g., iPhone 6)
- E-motor measurement not possible
- Readings are not accurate
- Cannot get a reliable reading
- Randomly skips between significantly different numbers
- Generates random numbers
- Does not recognize sound correctly
Requested features
5 requests- Save configuration settings
- Option to display cycle/cylinder count on home screen
- Improved response time for transient surges
- Simplified or automated setup process
- Auto-scaling graphical display for easier harmonic matching
Strobe Light
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Engine RPM
No in-app purchases
Strobe Light
- Remove Ads$5.991 Month
- Remove Ads$4.99
Questions
Is Engine RPM free?
Is Strobe Light free?
Which has better reviews, Engine RPM or Strobe Light?
Do Engine RPM or Strobe Light have ads?
Which is updated more often, Engine RPM or Strobe Light?
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