How to supply power to additional LEDs

[yathern2]

TL;DR: Skip to last paragraph

It's been well over a year since my last build, and I have a bit of money to spend, and wanted to get something else done before I run off to college again. I have an old ~95mW greenie, a wonderful 1.8W 445nm, and a bluray and a red one, both of which I got for free from WL (which was nice... but they both died a month later). So really, all I have now is blue and green.

I think it's time for me to make a nice, good red one. I got interested again after seeing the newly-discovered C-Mount 5W red diodes. Of course, I'm not about to drop $425 on one, but it piqued my interest in red again. The diode I'm looking at right now is the Mitsubishi 500mW multimode one I'm sure you all know.

The thing is, I want this build to be a bit more impressive than my last build (typical C6 host deal). My plan is to add LEDs under the tail-clicky, or in another location. The problem is, I have no idea how to do this. I'm decently familiar with building small electronics projects with Arduinos, motors and blinky lights, but I always achieved having multiple voltages through the Arduino. For instance, if I needed to have a light blink every time a motor turned, I would do it through software, because I'm a programmer, so that made a lot more sense to me. I have a basic understanding of electricity, and how a driver works, changing the current to what the diode needs. I've even tested quite a few diodes with an old variable DC power supply I have.

But in all of my experimenting with building simple electronics, I never got far enough to drive two components with different requirements. I would make my buildings complex in software, but extremely simple in hardware, because I can't make sense of it. A perfect example: the most complicated thing I built was an arduino hooked up to a piezo buzzer, button and LED. You could press the button, and it would play a song. The song was able to be programmed in through a GUI piano that I made myself, that included everything with timing and frequencies. Hardware simple, software complex.

My question is, how would I supply power to a diode, and LED with different input requirements? I feel like this has got to be extremely trivial to do, but I just can't figure out how to do it. I can't just wire them together in serial or parallel, right? Because the direct battery voltage is going to be too much for the LEDs. Maybe if I make an LED driver as well? At that point, I can probably just build it into the driver that drives the diode, right? You can see how I am confused by this.

 

[Leodahsan]

If you're not concerned with the leds 'dimming' with the battery draining (it lowers its voltage when its charge is ending) you need just a proper resistor (depends on led color and current) for each led. That way you will need to parallel the leds, each with its own resistor.

like this.
Don't insert the leds together with the laser diode.

If you wire leds in series, you will need more voltage.
If you wire leds in parallel, you will need more current.

By the way, tell us more about what power supply you will be using. Is it a single li-ion??

 

[yathern2]

Thanks for the help - I'm probably going to use two 18350s. I'll most likely drive the diode at somewhere around 800mA. In that case, the diode would come after the LEDs, Where you have 0V? Wouldn't the voltage be considerably lowered by the time it passes through the LEDs and resistors? I guess this doesn't really matter, as long as the driver is made to handle it.

 

[Leodahsan]

No no. At the driver output, you only connect the laser diode. Don't connect everything else.

Let me make simpler for you...
Commonly at the battery, you connect the driver. At the driver, the laser diode.
In your case, you will connect the driver to the battery, and the leds+resistors to the battery.

Gotcha?


edit:

lol I feel like drawing it. You can insert as many leds you like... the schematic don't include switches...

 

[yathern2]

Thank you so much! That really makes it a lot simpler for me, very easy to understand. For some reason, I was under the impression that electricity always, and only will take the path of least resistance, so if I wired it like you had drawn, it would only flow through the LEDs or something. Well this is a great relief.

My original crazy idea with how something like this would be done, was that the DC would have to be constantly switched between two outputs at like, 60Hz, and each one would have to have capacitors to even out the cycle. I knew that was probably insanely far too complicated, but I never thought it would be this easy.

It's funny, when you don't know much about something, your first reaction can sometimes be that the answer must be far more complicated than your skill level.

Once again, thanks a lot. +1 rep

 

[Leodahsan]

No problem. Don't forget that "schematic" I drew does not include buttons/switches, ie the leds will be on all the time.

Any doubts just post again or pm me

 

[yathern2]

Yeah, I think my plan is to include a toggle switch between both the driver/LEDs and battery, and another momentary button switch between the first switch and the driver. this way, when the laser is "primed" it glows red, and you can't use the laser unless it has been switched. I think I'll put the toggle switch on the tailcap, preferably a twisty type of switch. And the button on the side of the host.

I'm looking for a way to, instead of using LEDs, use some sort of strip that can glow, like EL wire. The problem with EL wire is it needs a big device to get it running. Not something I'd want to try to fit into a laser host. I've been looking at maybe some sort of fiberoptic, or diffusing plastic and put an LED at one end.

 

[Kookapeli]

If you want a led for the tailcap switch, they're are THESE

 

[yathern2]

If you want a led for the tailcap switch, they're are THESE

Ooh, that looks very nice! I'll look into using one of those, hopefully in addition to some sort of light around the front. Is there anything similar to that, which can be used somewhere in the middle? Like, screwed in between two parts? I wouldn't think so, because it can't be 'hollow'. Its a filled cylinder with the LED in the middle, if you get what I'm trying to say.