Well, in my quest to be able to build self-contained devices I decided that it was worth looking at ways to power my microprocessor and attached devices. Up until now I’ve been powering everything using the power supplied from my laptop’s USB supply – but in the future it’s going to be useful to be able to power my arduino (or ATmega micro) independently.
There are lots of different schematics available to produce a 5V dc regulated current, after searching around I chose one at http://stuff.nekhbet.ro/2006/06/18/how-to-build-a-5v-regulator-using-78l05-7805.html. I used this as the basis for my design, but I also added a quick blow fuse to limit the amount of current that can be drawn – the 7805 regulator IC the circuit uses has a maximum rating of 1A.
The circuit was drawn up in VeeCAD (which is good for designing stripboard circuits.)
The finished product fits on a 9×25 piece of strip-board and produces a nice steady 5 volts from my 12V power adapter.
9×25 stripboard (veroboard)
7805 voltage regulator
a ‘to220′ heatsink
10uF 25V electrolytic capacitor
220uF 25V electrolytic capacitor
fuse holder + a quick blow fuse
1n4007 rectifier diode
some terminal blocks – to make connecting to the regulator easier