#8 Low battery blinking indicator

This thought came out of the LED ring flash li-po mod, since the battery indication programmed into the microcontroller was "calibrated" for 100% being the 6v coming out of four full AA batteries, and (close to) 0% around 3.8-4v. Obviously, since a single lithium cell is only 4.2v when full, the stock battery indicator's out of whack.

Next step - i wanted a blinking indicator. Partially, because a solidly-lit LED would be a constant drain, and partially because a flashing light is more noticeable - think turn-signals on cars, or the emergency lights on police cars & ambulances.

#7 Cheapo ring LED flash / light teardown & li-po mod

I had been thinking about grabbing a LED ring flash for my camera for quite some time, but finally last week, i pulled the trigger on one. Cheapest of the cheap (from what i could find on the British eBay), but still cost me a bit under 30 bucks.

That being said, it's a reasonably well-featured package: four different coloured diffusers (that go onto the front of the LED ring), eight different size adapter rings (for lens/filter threads, and onto which the light clamps on to), and the control unit that mounts into the camera flash "hot-shoe". Also, the LEDs in the light "head" are split into two halves (ie. left and right), for <ahem> creative effect when using the ring flash for macro work.

The thing normally works on 4 AA's, buuuuuut... given some of the previous posts here, you oughtta have half an idea about my feelings regarding disposable power sources... <wink-wink, nudge-nudge>