LED_ASAP
Enlightened
Arc AAA\'s little brother
I have a few un-epoxied Arc AAA boards around (thanks to dpr /ubbthreads/images/graemlins/thumbsup.gif ), and a bunch of "pseudo-AAAA"s that were pried from a 9V battery (a half dead battery from my DMM). One day I was playing with the two and came out with this idea---why not make a small light that uses those cheap AAAAs (a $2 Energizer 9V battery has 6 of them inside!) /ubbthreads/images/graemlins/thinking.gif People have made AAAA tubes before so they can use an Arc AAA head with an AAAA battery. The run time is shorter, but it is still enough for most situations. So, the plan itself seemed feasible.
The AAAA's pulled from a 9V battery are a little different from "normal" batteries because they have negative nipple and positive bottom. So the circuit board was designed in such a way that the outer circle is positive and the central contact is positive.
The IC was taken from a stock Arc AAA board (I don't know which IC Peter uses, I wonder if he would tell us at some point like he did with LT1618 in the LS line). To make things fit in the 7mm circle of an AAAA-sized board, I have to bend the leads inward and turned the SOT-23-5 into a SOJ-5, then used a few 0603-sized diodes and capacitors. The stock inductor is too big, so I pulled a small 22uH inductor from a dead hard drive (about 2mm square). The end result is this:
I used a 3mm Nichia instead of 5mm, because I like the broader and smoother beam pattern of the 3mm. I suppose I could get a brighter hotspot had I used a 5mm.
Let's put it side-by-side with a stock Arc AAA board:
If we put battery sizes into the picture, we can see a light using AAAA batteries can be made much smaller than a stock Arc AAA.
I don't have the machining capacity, so I just used a piece of plastic tubing and a plastic cap to hold things together.
The beam shot with stock Arc AAA:
The AAAA light is a little dimmer here for three reasons---one, the battery itself is half dead already (remember it was from my DMM which already gave the low battery sign); two, I used a 3mm Nichia which has a broader beam; three, there was no reflector.
<font color="brown">I wonder if one of our lache/CNC gurus can make me a few shrinked down version of Arc AAA that will properly host the "Arc AAA's little brother".</font> It will be an interesting thing on the key chain---something you really won't notice until you turn it on /ubbthreads/images/graemlins/smile.gif
I have a few un-epoxied Arc AAA boards around (thanks to dpr /ubbthreads/images/graemlins/thumbsup.gif ), and a bunch of "pseudo-AAAA"s that were pried from a 9V battery (a half dead battery from my DMM). One day I was playing with the two and came out with this idea---why not make a small light that uses those cheap AAAAs (a $2 Energizer 9V battery has 6 of them inside!) /ubbthreads/images/graemlins/thinking.gif People have made AAAA tubes before so they can use an Arc AAA head with an AAAA battery. The run time is shorter, but it is still enough for most situations. So, the plan itself seemed feasible.
The AAAA's pulled from a 9V battery are a little different from "normal" batteries because they have negative nipple and positive bottom. So the circuit board was designed in such a way that the outer circle is positive and the central contact is positive.
The IC was taken from a stock Arc AAA board (I don't know which IC Peter uses, I wonder if he would tell us at some point like he did with LT1618 in the LS line). To make things fit in the 7mm circle of an AAAA-sized board, I have to bend the leads inward and turned the SOT-23-5 into a SOJ-5, then used a few 0603-sized diodes and capacitors. The stock inductor is too big, so I pulled a small 22uH inductor from a dead hard drive (about 2mm square). The end result is this:
I used a 3mm Nichia instead of 5mm, because I like the broader and smoother beam pattern of the 3mm. I suppose I could get a brighter hotspot had I used a 5mm.
Let's put it side-by-side with a stock Arc AAA board:
If we put battery sizes into the picture, we can see a light using AAAA batteries can be made much smaller than a stock Arc AAA.
I don't have the machining capacity, so I just used a piece of plastic tubing and a plastic cap to hold things together.
The beam shot with stock Arc AAA:
The AAAA light is a little dimmer here for three reasons---one, the battery itself is half dead already (remember it was from my DMM which already gave the low battery sign); two, I used a 3mm Nichia which has a broader beam; three, there was no reflector.
<font color="brown">I wonder if one of our lache/CNC gurus can make me a few shrinked down version of Arc AAA that will properly host the "Arc AAA's little brother".</font> It will be an interesting thing on the key chain---something you really won't notice until you turn it on /ubbthreads/images/graemlins/smile.gif
