DIY Red LED torch

[Brainstorm]

I'm thinking of building a red LED torch, this should be a very simple design, but I want to ask anyone who has an LED torch already if they are super-bright LEDs or standard red LEDs?

I already have a bulk amount of various coloured LEDs in my component collection, as I'm in the process of building a modular synthesizer. I don't have any super-bright ones, hence the above question.

I was thinking of soldering 2 rows of 5 LEDs on a couple of pieces of stripboard in parallel and attaching a 9V battery clip. With 2 individual rows of LEDs, I can also have it switchable between 5 or 10 LEDs (low & high power).

I'll do a build over the next week, put it into an enclosure and document it here with a list of materials needed.

[martin_h]

I wouldn't wire them in parallel If 1 led is slightly different it could destroy the circuit(unless you are using a resistor for each led).

Best to do it in series.

[RogerTheDodger]

I've converted a head mounted torch with normal brightnes leds ad it works fine for me. Also converted one of those laptop usb lights with them

[Brainstorm]

I'm now thinking of converting a bicycle rear light, bypassing the circuit that makes it flash.

I'll have a go with a few configurations, 2x5 LEDs might be too much drain on the battery for a start. I didn't think about wiring in series, since all the circuits I've built so far have never needed multiple LEDs wired to the same source.

I was thinking about the enclosure and the reflective shield (you don't want the LED glaring in your eyes, that needs to be hidden from view, so I'll attach a reflective box around them, that way it will direct the beam and shield the direct light from your eye. They sell disposable roasting trays in Lidl for 49p, which are made of very thick tinfoil. I was thinking of cutting up something like that.

[RogerTheDodger]

Brainstorm, that synth looks brilliant... is it based on Moog filters or another design? I seem to remember one in Elektor or something late '70s early '80s...

[Brainstorm]

Thank you. It's various circuits, some are buchla clones, some ARP, some just made on stripboard, basically clones of the best parts of my favourite classic synthesizers. the only thing missing here is the oscillators, and that's purely down to the availability of tempcos. the suitcase synth in the pic is one of my contraptions too, which does have oscillators.

Anyway, back on topic, I just picked up the Sky @ Night mag, and that has a led torch tutorial on page 76, although it does look rather bulky with all the terminals. I guess that way is better for folk without a soldering iron, although I find most people have a soldering iron in their tool box these days.

I wouldn't recommend Maplin for components either unless you want to spend twice what a manufactured torch would cost for a DIY one. For example, metal film resistors singularly in Maplin are 24p, whereas Rapid stock them at 99p for 100 (less than 1p each), which makes it more than 2400% more expensive at Maplin!