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FrozenGate by Avery

Is This Wrong >>> Using Dorcy Without Driver Just A Resistor

Yeah, I recommend the Flexdrive, like Jay says. It rocks! So small yet, so powerful. Great design that fits even inside the Aixis module, but I don't recommend that unless you really have to, because you are putting the power supply inside of the heatsink assy. LOL Edit: Oh and yes Jay has been providing some of the best Hosts and parts seen anywhere on the planet. ;-) Thanks Jay!
 
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Alexizupinhea said:
Umm, I don't really know what you all are saying^^, but basically, YES you can use just a resistor in series with a red LD using the circuit driver inside the Dorcy Jr. As Kenom said, he's done it as well as many/some other members on the forum (including myself). I was also cheap, and mine's been holding up fine for months now. However, I'm not sure quite how you would build one without a heatsink. Jake21 (not really a member here anymore) built my heatsink for $10. But, if you plan on going without a heatsink, you should at LEAST try to use a washer or two. Just drill out the inside of the washer to fit the aixiz module inside. Then grind away the outside of the washer until it fits inside the host. Basically, you can do it and build it for cheap. Also, MAKE SURE YOU DO NOT USE A 3.6/3.7V RCR123a BATTERY WITH IT. ONLY A 3V Primary (non-rechargeable), or 3V rechargeable (DX has one pair of 3V RCR123a - I personally use that with my Dorcy). And, I believe they said a 5ohm resistor is ideal, but I think I personally used 4.7ohm or something (don't remember exactly). And, I used a closed can diode, not an open can... but really there is not too big of a difference. However, I believe people said a closed can (normally in a DVD burner), is better to use than the open can, when doing this Dorcy build.
Click to expand...


You can use a 3.6v rechargeable with a 5ohm resistor and the dorcy Jr Driver. At max charge it will send 290mA to a 16X red diode. As for a Capacitor, there is already one inside of the Dorcy driver, plus a battery supplies the most constant current flow that you can get. (aka-no Spikes)

In the end, this can easily be done, but you should definitely include a heat sink.
 
just spend 14 bucks on a rkcstr driver...

and cut him some slack guys, he's from EGYPT... they dont do electronics like we do over here... but i've been trading PM's with him for a while now. he's trying to find an affordable way to introduce lasers to the public in Egypt.

i can completely understand why he asked a question like that... he didnt know how it works around here.

just figured i'd shed some light.

i think its great that there is interest in regions such as his.

Dark
 
I thought I might ask this in this thread without starting a new one.. I'm looking to do something similar except even MORE simply..... I have the host, the diode, heatsink, but no lava drive, no rckstr, and no stock driver for the host. (Don't ask me how I lost it). I do however, still have the pill that still provides a good connection to the cell via solder contacts on the star shaped plate. Just for having a working blu-ray, I want to just use a resistor and capacitor that would each be the only things separating the PHR from the 3 volt cell.

However, I wasn't aware if there would be any advantages or disadvantages to having the resistor in series with the LD and cap, or having the cap parallel to the LD and resistor which are in series to each other.. any suggestions?

(yes I'm aware that there are still risks to having zero regulation, but I will be happy with some simple and fundemental current limitation and LD protection.
 
Sorry for being blunt, but having a basic knowledge of common electronic components, like capacitors, is really desirable. If you put the cap in series with LD and resistor, current will flow for milliseconds until the cap is charged and then no more (to be precise, you'll get an exponentially decaying charging current with time constant 2pi R C ). The cap goes parallel to the LD (and if you're just using battery and resistor, the cap is not needed at all - its purpose is to "smooth" out any AC components in the current).

Also, for a PHR, you need more than about 4.5V input (you have to measure it or look in the forum for some U/I-graphs), i.e. 2xCR123A - or a FlexDrive (very tiny, very sensitive).
 
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Maybe I didn't explain it well enough. Here's a simple schematic..

I forgot about the higher voltage needs of the br. So if an LPC were used... which one of those circuits would work best off of the cr123? Or is there even a difference?
 

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  • Dorcy Circuit.jpg
    Dorcy Circuit.jpg
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Ah so. Well, first and again, with a battery, you don't need a cap at all - it provides the smoothest current possible. With a battery and a driver, you don't need the cap either; it should be part of the driver. For the FlexDriver, which employs a HF frequency switch, you need special low-loss caps with very short leads anyway (so it has to be part of the driver PCB). For the LM317 type, it's best if you check what the datasheet says.

In conjunction with an AC power supply, a cap might make most sense - but again, having it in the power supply would be best. Generally I'd say, don't put a cap in.

If you did have a power supply with some remaining ripple, then I actually can't say right away which would be better - I'd need to know the expected frequency and amplitude and do the math. My gut feeling would vote for the 2nd schematic (essentially a low pass).

EDIT: depending on the Vf of the diode, you'd need a resistor with about 1.5..2 Ohms. I'd start with about 5 Ohms, measure the voltage drop over the LD and the resistor (which also tells you the current) and then work my way down in steps to the target current.
 
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