High Power LED Head or Bar Mount Light

Building LED lights is easy with 'puck' or other type drivers. The main advantage of this project is the circuit with visual 'blink' low battery warning. The aim here was to make a helmet mounted light, but you could also fit something like this to handle bars of frame.

Wanted to share the circuit and also the method of construction for the lighting enclosure which worked out quiet well.

There are many variations that one could make here. With a higher voltage battery pack, the circuit will drive at least 2 more LEDs (6 in total) or less could be used. Different optics or mountings could also be used.

As there is already quiet a detailed work log on NoBMoB please check there: Rob's Homemade LEDs.

Have just included a couple of brief steps, please visit the above for the details.

Step 1 Circuit Design

Using the brilliant Eagle CAD software, make the schematic then lay it out on PCB size chosen for your enclosure.

The circuit below uses rudimentary logic to turn of the main LEDs with the simple flasher and 'low' battery warning - in effect this 'blinks' the main LEDs when the battery is getting low.

A second voltage comparison turns of the main LEDs when the battery pack voltage is getting too low, to prevent over-discharge. What's good here is that in doing so raises the input voltage and we get a feedback loop that actually causes the main LEDs to dim nicely rather than cut out abruptly.

Comments

[nikkynixx]

Very interesting. I just read an article on line that goes into detail about series strings of 6 or more LEDs. Apparently the problem is that the forward voltage can vary and with a string of 6, the increase is very significant. Sometimes the source voltage may not be sufficient: http://www.lunaraccents.com/nav-custom-LED-lighting-design.html