A Timegrapher. This app is to measure the BPH of mechanical watches. It will display time error per day as well. The app uses microphone to measure BPH. Recommend to plug a microphone into phone and attach the microphone to the back of your watch. Basic version display wave graph and pulse interval histogram. Frequency display requires 'Premium' upgrade.
Download the latest .apk setup package of Clock Tuner 2.11 free of charge and check out users' reviews on Droid Informer. You will need 3 MB of free disk space to set up the app. According to the antivirus report, this application doesn't contain viruses or any kind of malware. BuzzSoft is the developer of Clock Tuner that is listed among the Tools category.