Add support for TM1637 key/button input

[timwaizenegger]

I've noticed that the TM1637 has two pins that you can use together with the LCD-grid pins as a key/button matrix. apparently you can connect up 16 buttons this way and read their state via the serial I/O.

It looks like very few off-the-shelve display modules for arduino/raspberry use this feature but it could be very useful in custom applications. When you're using a display it's most likely for a UI, so usually you'll want some buttons as well...

I found no arduino TM1637 lib that implements this feature. Your library seems very complete and ambitious; maybe you're interested in adding this 👍

[timwaizenegger]

I did find a library that seems to implement the feature; might be useful as a reference.

https://forum.arduino.cc/index.php?PHPSESSID=lpd0td3f2499n2i2jo1uq1atg6&topic=360318.msg2612868#msg2612868

[bremme]

Hi Tim, thanks for your feedback! There is already a low level method which should be able to read the key matrix (uint8_t SevenSegmentTM1637::comReadByte(void)). But I never really tested this since I didn't had a TM1637 display with connected buttons. I think I do have one now, if I can find it:). I'm going to have a look at this.