Acoustic Ruler Pro app for iPhone and iPad

4.4 ( 5584 ratings )

Utilities Productivity
Developer: Florian Student

1.99 USD

Current version: 4.4, last update: 7 years ago
First release : 01 Nov 2011
App size: 3.24 Mb

[Please also check out my app Sonalarm, the first sleep cycle alarm clock app that works from your bedside table with NO additional hardware!] Wouldnt it be amazing to have a ruler in your pocket all the time? Well now you can! Measure distances of up to 25 meters (82 feet) with two devices or up to 1.10 meters with one device and headphones.
Click below on "Florian Student Web Site" or open www.iq-tainment.com to watch two videos demonstrating the app.

Acoustic Ruler Pro has been featured on Cult of Mac, Techcrunch, GIZMODO, lifehacker, and MAKEZine.

The app works by clocking the time delay of the emitted sound waves. There are two different operation modes: a single device operation (with headphones) and a dual device mode for measuring the distance *between* two devices. Read below to find out which modes work on your iOS device.

Single device (headphone) mode:

This mode works on the iPhone 3GS (and newer), iPod Touch 3rd Generation (and newer) and on all iPads. You either need one of those devices and headphones with a mic or headphones without a mic and a iOS device with a built-in mic (excluding the iPod Touch 3rd Generation). The resolution in this mode is 1mm or 1/10 of an inch, depending on the unit system you have selected.

Dual device mode:

For this mode you need two compatible iOS devices. These are: iPhone 3GS (and newer), iPod Touch 4th Generation and all iPads. One device has to be started as the master device, and the other as the reflector device. The measurement is started on the master device, by pressing the “Measure” button. The reflector device then sends back the chirp of the master which displays the measurement result. The resolution in this mode is 1cm or 1/2 of an inch.

When you first start the program, it will guide you through the easy calibration steps with text and illustrations explaining what to do. Please recalibrate when you are getting wrong measurements.

The app lets you set the air temperature as an additional calibration. This is important, because the speed of sound varies considerably with temperature, affecting the precision of the measurements.

You can switch between displaying the measurement in feet/inches and meters/centimeters. Accordingly, the air temperature will either be set in degrees fahrenheit or celsius.

Since the app works by sending and receiving sound, you’ll obviously get the best results when using it in an environment that is not too loud.

Starting with version 4.2 of the app, the measured latency (delay) is also displayed. Double-tap the display of the distance to swap the locations where delay and distance are displayed. This feature was added because a couple of users of the app thought it could be useful to measure latencies in their audio systems. In the dual-device mode the displayed delay corresponds to the delay from one device to the other (i.e. half of the totally measured, round-trip delay).

If there are any problems with my app, please let me know by using the contact form on my blog. I will do what I can to get it working perfectly on your device. Customer satisfaction is very important to me.

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Follow @acoustic_ruler on Twitter to stay up to date with the newest developments, or to report any problems you may have.

Pros and cons of Acoustic Ruler Pro app for iPhone and iPad

Acoustic Ruler Pro app good for

Tried various distances up to 5 meters and down to a few cm, the app has been accurate to at least one cm and has worked every time. Great stuff, this is what I call innovation.

I use it fairly often to measure distances. Its pretty reliable and works as well as a tape measure for short distances!

Measures from microphone to speaker and NEEDs headphones for 1 iPhone use. Distance to be measured is limited by how far you can separate speaker/mic on your headset. Longer distances need 2 iPhones/iPod touches.

What a useful tool. Works very well, and well worth buying. I highly recommend this App to everyone!!!

This cant come close to replacing a tape measure obviously, but its still fun and not bad for estimating.

英語表記でわかりにくかったですが、図に描かれている通りにしてみました。まず、「Single Device Operation」モードで「Ｌ(電子音が流れる)」のイヤホンをマイクにくっ付けて基準値を設定。その後、「Ｌ」側とマイクの距離が表示されます。私の場合、少し誤差が出たのですが、こんなものなのだろうと思いしばらく使っていました。しかし、画面の下に気温を設定するバーがある事に気付き設定。すると、驚く事に誤差がほぼなくなりました。 iPod touchがあったので「Dual Device Operation」モードにも挑戦。音でそれぞれを認識するのでBluetooth接続等の面倒な設定は必要ありませんでした。「Master Mode(メインとなり、距離が表示される側)」と「ReFlector Mode」をそれぞれに設定し、iPhoneとiPod touchのお尻同士をくっ付けて基準値を設定。その後は「ReFlector Mode」の側を測り始めたい場所に置き、「Master Mode」側で(Measure)を押すと測定されます。メジャーを横に並べて比べましたが、2.5mの距離でも気温の設定が合っていれば5mmも誤差はありませんでした。十分使えます。あと、音量が小さいと届きにくいですので測る前に大きくした方がいいです(設定があまりに小さいと親切にもポップが出て来ますが)。

Some bad moments

Failed to measure anything over a foot and change (in single devise mode). Also kind of awkward to use. In any case its a cool little toy for about 5 minutes until you realize how unhelpful it actually is. At least it was only a buck.

It measured the width of my MacBook Pro as 50 cm. The actual width is 39.3 cm. A useless gimmick.

Waste of time and money, try it 10 minutes in the garage, living room and it never show the right mesures, concept is cool but it need major update.

A measurement with two iPhone 4s devices at 30 ft was accurate to within half an inch (and the 30 ft measurement with the tape was just eyeballed). Theres some impressive software in here!

Its not something you need everyday but thats the whole point of this App. You have it when you need it and its cheap enough that anyone can just download it quickly in case you need a second phone. Ive used the small screen bases ruler app quite a bit and was always hoping for an app that could measure longer distance. Love it.

Pretty cool, although it is loud. Got accurate measurements but my coworkers thought I was sending out an anti riot weapon!

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