I will use a voltage regulator to allow for a flexible input and to make sure that the output remains at 5V. I will be using a 7805, which will allow me to use an input voltage in the range of 7 – 25V. The 7805 can be used with currents up to 1.5A. I don’t imagine that the current requirements to be anywhere near this. At high currents the 7805 will need a heat sink.
The voltage regulator will work without any additional components but to improve stability and to reduce inductance, I will add 2 ceramic capacitors. These should be as close as possible to the terminals as possible. Capacitors will help to clean the output. The reason why I will use ceramic capacitors and not electrolytic, is that they are faster.