In order to finalize our prototype and our project, we decided to solder the components of the Music box on a printed circuit.
Here is the scheme of the circuit:
We then designed our printed circuit board using the EAGLE (Easily Applicable Graphical Layout Editor) software, which has a freeware version available. To learn how to use this software, we found a tutorial on Sparkfun. We added two different libraries on EAGLE in order to find our specific components. Both libraries are on github, the first one is Adafruit, and the second one is Sparkfun.
Components of the circuit: 1 arduino uno, 2 potentiometers, 2 push buttons, 1 RGB LED, 1 piezo speaker, 5 resistors.
The design of the a printed circuit on EAGLE happens in two steps :
First we created a schematic with all our components routed:
Then we designed a board from the schematic:
Once the design of the circuit was done, we printed both sides on two plastic films and we superimposed them in order to have each on one side of the copper plate:
Then, we went to the laboratory and followed a specific procedure to create the printed circuit including several washing steps of the copper plate, photoresist covering of the plate, printing of our circuit onto the plate with UV light, acid engraving …
We printed it twice in case something went wrong. After that, we checked with the microscope that the printing was correct, we drilled the holes and we cut the circuit to have the following final result:
Finally, the last step was to solder the components on the PCB but we didn’t have the time to finish that yet.