I managed to get my hands on some bright white LED’s, however they weren’t the ones described in the initial post . I am still unclear to which model they are as I am still waiting on the datasheet (thanks a lot again GT Electronics -always get attitude in there). Anyway, I was assured that the stats on these were as follows:
Forward voltage – 2.3
Current draw – 20 mA
Intensity – 20 000 mcd
So far they look up to the part, bright as all hell. However this required a change in resistor values. As the forward voltage in multiples is still less than 5 volts, we can put 2 LED’s in-line, and the combined voltage is 4.6. If were going to be technical, and we are, then we still need to account for the difference of .4 volts.Honestly, it will probably run as is, but lets compensate for the excess voltage and maybe make sure the LED’s last longer.
Thanks to uncle Ohm we know v (volts) = I (current) x R (Resistance), and here we want the value of the resistor (R=V/I), so we need R= the voltage drop (.4) / the current draw of the LED (0.02) = 20 ohms, closest higher value is probably 22 ohm. So schematically it looks like this:
The current draw across the array is expected to be roughly 160 ma (20 ma per bank, 8 banks). On a 2000 mah pack, we should be able to expect the torch to run for 12.5 hours non stop. Pretty good, especially considering how bright 16 of those little bastards should be.
I have started work on the unit, but the eagle eyed should notice 17 LED’s and not 16, over eager soldering syndrome got the better of me, ill just pull it out later.
Next to do is put a resistor board together, cut through the tracks where they run through all LED’s, wire up the resistors to the rear of this panel, hook up a switch, and make a case. I am planning on either 3d printing a mould and using acrylic if I can find it or simply bonding the whole lot into a 3d printed frame, however I am much more interested in seeing if I can make a clear acrylic unit with this.
So until next time, get out and build something of your own.