A fundamental task on the real project was to identify the electronic components needed to realize the idea.
So the very first thing I did was to simply hook up a few components I had at hand and play with them. As I had the ‘clever’ idea of integrating a universal power supply (UPS) on the board, I ordered a few ultra capacitors (10 and 20 Farad) and hooked them up with some resistors. I burned one of the capacitors immediately because I was so excited that I forgot I had to use at least two of them in series for a 5V setup (one has a maximum voltage of 2.7V, which I knew). Doing it right I was able to confirm my assumptions about the maximum current flowing through the components. I find these little ‘in series’ USB adapters pretty useful for that purpose. They give quite accurate readings for what they are and what they cost. These little devices even integrate the current over time, which is a useful feature. I only own cheap amateur electronic tools which (at least for my projects) suffice most of the time. I discarded the whole UPS circuit much later.