Inspiration

Some short videos seem funny that YouTubers use dialing keyboard of their mobile phones to play short music. Wouldn't it be a little suprise for friends to play a birthday song as a gift? After several attemps, I found the sequence of taping the keyboard must be remembered, which can take a lot practicing. Fine, let's automate it with ADB and python!

Equipment

Huawei mate 20 (without root), USB cable or wifi, python3, ADB

Basic Idea

• Create a library of music scores in txt files. In each txt file, there are lines of series of numbers and *, #, which represent the sequence of tapping;
• Read txt file and interpret it to (x, y), in which x, y represents the (x, y) coordinates on the phone screen;
• Use OS.system() to call adb shell;
• Use adb shellinput tap x y to create tapping event
• Endless loop fr user to choose different melodies

Run

1. Use te USB cable to connect the phone and PC;
2. Tap the Build number several times to open Developer options
3. Enter Developer options and turn on USB debugging
4. Run the Faster.py on the PC. In the library, there're BirthdaySong, Little Star, He is a Pirate, City of Sky. Piano solos are suitalble to play.

A possible way to speed up the tapping

After running faster.py, most of music snippet sounds fluent. I'm amzeed at how simple it is to creatte beauty, meanwhile, I find the rythm is a bit slow for some music, like He is a pirate. After googling, I found that input tap is a java application, and that delay is actually the time required to spawn then run it.

The first thing I did was to change MelodyGenerator.py to Faster.py. The main difference is reducing the times to use os.system(). Because it will start a new subprocess each time. It would save some time to call it once for each snippet, and then pause, then next snippet with a new os.system(). But this method wouldn't make an obvious difference.

A possible way is to root the phone and use dd to record your taping and then replay the record. This blog inspires me a lot. However, rooting a new phone is risky. I tried that method and found permission denied in ADB shell while replaying the record.