gStrings was originally released as two separate apps: an ad supported free version, and a paid version without ads. This was back in 2009, when in-app purchases were not available. With regards to functionality, they are the same.

Waves was written for Google's (then new) Holo design; it is now deprecated.

Yes. Download and install the last version of the app before the rewrite from here.

Please note that this is the ad supported version only. Restoring your previous purchases in the old version (keeping this functionality working alongside the new one) would have been a lot of work. Thank you for understanding.

No. But you need to understand how purchases work on Google Play (identifying the gmail account used when the purchase was made), and you must know exactly which item you have purchased.

You need the app with said item installed on the device, with its purchase status restored (happens automatically when you first run the app).

Other apps (ones you have not paid for) will then be able to query and verify your purchase.

Search the questions below for mode details in specific cases.

Search your archived emails for the 'gStrings' or 'Waves' keywords, since Google sent you an email with the purchase details when you made the purchase. Otherwise you will have to experiment:

If you purchased gStrings (the paid version), Play Store will show an 'Install' button instead of a button with the price when you attempt to download it.

If you purchased one of the in-app items in gStrings Free (disabling ads), or Waves (unlimited usage), just install the apps from Play Store and run them. Both will automatically restore your previous purchase status, provided that you have installed them using the same gmail account as you had at the time of the purchase.

Please follow these steps:

1. identify the item you have actually purchased (see Q above). You may have purchased the in-app item disabling ads in the free version, or you may have purchased the paid version instead,
2. identify the account linked to your purchase (the gmail account Google sent you the purchase details to),
3. run Play Store, and uninstall the tuner,
4. make sure the currently selected account in Play Store is the one identified in (2) above,
5. reinstall either the ad supported free, or the paid version of the app according to (1) above,
6. run the installed app -- purchase status will restore automatically.

If the above steps have not helped, you may just have encountered an unlikely temporary Google Play caching issue. Please take the time to read/understand the steps and try again a day or two later.

Yes. Please follow these steps:

1. identify the account linked to your purchase (the gmail account Google sent you the purchase details to),
2. install Waves from the Play Store, making sure Play Store's selected account is the one identified in (1) above,
3. run Waves, go to its Settings tab, scroll down and make sure it's 'Purchase status' reads 'Purchased' instead of 'trial',
4. install gStrings from the Play Store,
5. run gStrings, go to its settings (pulling the sliding bottom drawer out), scroll down and select 'Advertisements',
6. click on the 'VERIFY' button to query Waves for its purchase status, resulting in ads being disabled.

Yes. Waves has the same kind of verification built into it, as gStrings (see previous Q). However, you should not be using Waves, since both it's UI, as well as its functionality is inferior to gStrings'.

There can be a number of reasons for this. Some of the most common ones are:

1. you have used some third party app (e.g. a backup manager) to install gStrings,
2. you have side-loaded an installation APK,
3. you are experiencing a temporary Google Play Services caching issue.

These (and other similar) issues can almost always be resolved by:

1. uninstalling gStrings,
2. rebooting your phone,
3. installing gStrings from Google Play Store again.

The app has two operating modes:

1. automatic target tone selection,
2. manual target tone selection.

You can switch between the two modes using the button with a lock on it that keeps sliding in and out on the right edge of the screen (tapping the main widget area of the screen will slide the button in/out).

In automatic mode the app will switch the target tone (the middle value on the top list of sliding tones) to one that is closest to whatever it believes is the most significant fundamental frequency around the phone at any given moment.

In manual mode the app will not be changing the currently selected target tone. While it will continue to measure sound input in real time, only the needle position and Hz result are updated.

It's best to keep the app in Automatic tone selection mode. This way you wont have to fiddle with the app as you go from string to string on your instrument.

The thin bottom bar (with the upward pointing triangle on it) is a sliding bottom drawer. Pull it out!

The circles represent the list of target tones useful for your particular instrument (strings, if a stringed instrument is selected).

This is to help you out in case you were not sure about the tuning (tones assigned to the strings) of your instrument.

You can change the list of target tones by selecting an instrument from the list of instruments (first settings item).

I could, but you can too! The app supports custom instruments. Just click on the big round floating + button in the lower right corner of the list of instruments!

If you had to ask, please make sure it is set to 'Equal tempered'.