SOFTWARE for PIC16F628: Program code is written using MikroC v8.2. Size of code is 1,8 Kb which is within demo limit of MikroC. You can use any other PIC for this purpose, but if you use PIC16F628 as I did, there is no need for external crystal, because PIC16F628 has an internal oscillator at 4MHz. If you want to use different PIC, make sure that you make propper changes to MikroC and recompile.
Links to some usefull web sites.
To build this project you'll need PIC programmer...
Donations are appreciated.