Last year I built a very simple power supply unit, The idea being that I can use the dupont leads to connect a to a breadboard. Linked to this was a 5v version. I have no modified my original design to include a built in volt meter pictured below.
Having the meter soldered on the board is really useful, as it means I can plug a battery (usually 9v) and see exactly what voltage I have going in from the battery (or batteries) and therefore how much is going OUT at the other end (as the voltage drops as the battery is used). This is useful as under powering projects causes all sorts of random issues.
Next step will probably be to check the 5v PSU project works properly. Well it works as long as the battery powering it is new. May try some decent batteries, as the ones here are cheap ones from Poundland.