Designing the electronic for an already existing shell is much cheaper than to produce a shell to fit your design… So I did the other way around, I found the shell that i liked afer many test.. and then I started to design the PCB
What you need is to learn a cad for this purpose, and then trying to make the PCB with different techniques… Obviously the password is STUDY...
I decided to learn EagleCad, on Internet you can find plenty of tutorials... then I started to experiment..
I wanted to keep everything small and light. So I chose the microcontroller AT MEGA 328P AU.
I decided to give a try to the laser printer toner technic. It works in this way: you print the circuit on a heat transfer paper by laser printer. The toner is a sort of plastic; therefore when you will put the copper plate in the acid it will not corrode the copper under the toner (the circuit).
To transfer the toner I bought a grandma ironing… first time in my life…. Then I used it also to solder the SMD components, checking the temperature with a laser thermometer, trying to follow a reflow curve.
Obviously it takes some practice to understand the right pressure and how to manage the temperature.. but after some try it was ok…