Arduino: bathroom (night)light prototype mobile edition

I finally acquired a battery pack, DC main connector and a few crocodile clips to make the prototype portable. I opted for a 4 AA battery pack, because I heard/read somewhere that the 9V batteries don’t last very long, where as the 6 volts my battery pack spit out will last longer. Not sure where I heard this, but when I find the proof I’ll post it here.

The DC mains connector was slightly trickier to source, mostly because I didn’t know what size to pick, I guessed that it would either be a 2.5mm or 2.1mm. In the end I confirmed it was 2.5mm through the Arduino documentation site.

I found this colour photo on LadyAda’s site showing which wire to connects to which pin. Red (Live/+) goes to the center pin and the Black (Neutral/Ground?/-) goes to the outer pin.

The only thing left to do was to change the PWR_SEL from USB to EXT to go wireless! I beamed with pride as I saw my little prototype splutter into life without the aid of its USB cable. Twas only a brief moment, because I realised the damn thing wouldn’t fit in the “casing” I had provisioned hastily from last night’s take away.

Luckily I circumvented disaster, by swapping to a smaller bread board I’d bought, obviously some psychic abilities kicking in there. Next up are some photos and then I’ll conclude my findings.

The p-type in its coffin, um casing!

Side shot

Under carriage shot

And finally an action shot!

Not a bad start, rather pleased that the takeaway box makes a tidy casing. However, the light is weak, VERY weak. So I think we’ll need about five if not more LEDs, preferably yellows or better still whites. So I anticipate more output pins, I managed to run two LEDs in series, but a third refused to light so I can only assume I ran out current.

So watch out for the next mini project which involves discovering how many LEDs it takes to make a night light!