I did several projects with PICs before that's the reason why. I chose this PIC cause this is a very allround PIC, very cost effective, lots of I/O so no need for a key matrix unless you want more buttons. An INT port, HW serial port, internal OSC and so on. I could use a PIC18 at higher speeds but I think the PIC16 is fast enough.
The interrupt on change pins that are available are used for the rotary encoders. This way they are very responsive and reliable. I tried reading them on regular pins but that gave me not wanted results. The other buttons are read in a loop, the program runs fast enough not to miss a keypress.
The cost of the PCB is not much.
-16f887 at 4 euro
-headers at 2 euro
-cables are old ones I reused
-analog multiplexers are 0.5 euro a piece, 2 are used
-inverting schmitt triggers cost 0.3 euro a piece, I used 3
-7805 and the rest of the parts set you back around 2 euro
All together you build this for less than 15 euro including a PCB.
To honest I was going to use an arduino first, just to explore the platform but I didn't like the way it was programmed compared with the CCS compiler I'm used to. Though, I'm sure you can do it as easily on an Arduino.
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