Streamlight Sidewinder Mod - Plans & Thoughts

[Balefire]

So for my first serious mod I'm looking to take a Streamlight Sidewinder and modify it to better fit my needs. Basically, I'm happy with the concept of the light, but I need more than the weak output on Red and the Twist/Push UI doesn't really do much for me. The White LED is also not particularly efficient and because of the way that the board is set up it's not easy to do a LED swap.

So here is my plan:
Pull out all the guts, including the driver and switch, and replace the switch with a sealed rotary.

I plan to use a Cree XP-G and an XP-C Red (each with 10mm optics and holders and 350mA micropuck drivers) and three 5mm LEDs with resistors to give me five selectable modes:

5mm IR, 5mm Red (Low), 350mA XP-C Red (High), 5mm White (Low), and 350mA XP-G white (High).

I'm hoping to get around 60-70 lumens of white light and 40ish lumens of red on high, with the 5mm settings outputting just enough to read by.

My major problem is that I have minimal experience with electronics, and while I do know how to solder and should be able to handle the fabrication parts of the build, I'm not sure if the way I'm going about designing things is sensible or efficient. I'd like to follow a KISS philosophy, and minimize chances of breakage or points of failure.

Here's my plan for wiring:


and here's my plan for the modded front of the light (approximately to scale):


The light runs off 2xAA batteries, and I plan to keep it that way.

My questions are: Is this the best/right way to wire the light?
And, how do I run a 5mm White led off 3v? Do I need a boost driver for that too? I know I have a resistor in the diagram but that's wrong, no?

Comments and suggestions appreciated.

 

[ozner1991]

i think this might be a little to complicated for a beginners mod imho. id look around first and try some other mods before trying something like this.

now about your plan, i have no clue if you have enough heatsinking or space to place one inside the bezel. i dont know howmuch heat an XP-G creates and howmuch heatsinking it needs to work efficiently.

there are some more experienced members on here, i hope they have more usefull information

 

[Balefire]

Well, may as well jump in with both feet!
I've done some emitter swaps and such, but after a fruitless search for the right light for this job, I've decided the solution is to make one!

As I said, I'm mostly concerned about the wiring. Heat shouldn't be too much of an issue - the stock LED runs at 1w and I'm going to be running the new, more efficient XPG at the same 1w (probably with better heatsinking, as well).

 

[dirtech]

How does the switch work?

 

[Balefire]

It's a rotary switch, 6 position...
So, if I am reading the datasheet correctly, I would connect the battery lead to the center pole of the switch and then there are 6 pins to which I can connect the leads that go to the LEDs.

Each position of the switch should therefore complete a different circuit.

However, I am not sure at all, and that's why I linked to the datasheet in the first post.

 

[dirtech]

I'm no expert but I don't see why you couldn't run the appropriate valued resistor, if one is needed at all, on the 5mm LEDs. I didn't see a link to any data sheet for the switch, maybe I'm blind?

 

[Balefire]

Ah, sorry.. I meant to include it, but I guess it got lost somewhere in the drafting of the post. Here it is:
http://www.grayhill.com/web1/images/ProductImages/Rotary_50,51.pdf

My issue isn't with running the IR and Red 5mm LEDs - both have forward voltages under 3v so I can use a resistor calculator to get the right results.

All the White 5mm LEDs I've seen, however, seem to have forward voltages above 3v, so will one even light up off 2 AAs?

 

[dirtech]

That would be easy enough to test. Hook one up with 2 alkalines and see what you get.

 

[Gryloc]

For the most part your idea seems relatively solid, plus you have recognized most potential issues (Vf of 5mm white LED and the heatsinking). You will fit right in at the CPF!

I have a crazy idea: Your XP-G emitter has a forward voltage of about 3.0V at 350mA. As the current decreases, so does the forward voltage (within your 3V requirement). Therefore, you could feed the XP-G about 2.7V and the emitter will draw only about 40mA of current! For a reference, I am using the test data of a XP-G sample tested by jtr1962 (link).

Since you have a rotary switch, each output of the switch should be isolated. If they are isolated, you may be able to direct drive the XP-G from the 2AA batteries or use a resistor to it (completely bypassing the little boost driver). This would allow you to have the same wonderful efficiency, color, and beam pattern you like with the XP-G but with a reduced output (to match the cheap 5mm LED in overall brightness). This means you could parallel a second 5mm IR LED in there to increase the output in that wavelength.

So you can put a resistor between the +out of switch position 4 directly to the + pad of the XP-G star. Therefore when you switch to position 4, the XP-G may get like 30mA with the current-limiting resistors (MicroPuck bypassed), but when you switch to position 5, the circuit is broken to the resistored XP-G then connected to the input of the MicroPuck driver to send 350mA to the XP-G (you can get 500mA versions as well if the light can take the heat) . The circuit back through the resistor of position 4 is not connected to anything, so no current will be drawn.

Meanwhile, you can fill the spot next to the first resistored IR emitter with another IR emitter that is resistored like the first.

One more crazy idea is to do the exact thing with the Red XP-C emitter. Position 2 could power the red XP-C with a resistor in line to power it at 30mA like the white. As a result of this, you could now power 3 IR emitters in those 5mm holes (since 5mm IR emitters could be kind of weak if you need it for night vision equipment).

Is that too crazy? Well, you need to make sure that the rotary switch utilizes a break-then-make connection (it breaks contact to one position before making a connection to the next position), and you do not want a make-make connection (two positions are powered at the same time).

As for heat, you will have to experiment with this. If you have a thermometer that you can shove in the half-closed plastic body, you may get a rough idea if things get too hot on the heatsinks you attached the star MCPCB to.

Related to heat: I did some math and I found that the XP-G (R5 bin) is about 50% efficient overall at 350mA, so that means about 0.54W of the energy that you are feeding to the emitter is being emitted as visible light, and the other 0.52W is being wasted, generating heat. This may be good news since 0.5W of heat may be manageable!

As a comparison, an old Lumileds Luxeon emitter (R-binned) which generated about 45 lumens at 350mA was only about 13% efficient at that much current. Therefore about 1.09W of heat was generated while only 0.17W was used to generate visible light. The advances in efficiency really helps us flashaholics by allowing us to have brighter and cooler lights that use less battery power than previous generations of LED emitters!

As a little side though, one may ask why use a boost driver for the white LED if it draws 350mA at 3V. Under use/load your battery voltage is going to drop a bit (especially since you are using 2AAA cells), so the driver may need to boost the voltage in order to maintain the 350mA of current. The same can be asked about the red XP-C, but I believe that the higher power red LEDs could have a lot higher of a forward voltage compared to their 5mm brothers. However, I do not have any test data to show. You can check out the Vf versus current data on Cree's website by viewing the datasheets for colored XP-C emitters.

BTW, if you cannot get ahold of a red XP-C, you could use the Lumiled's red Rebel emitter as an alternative (compatible with your optics and easily available). Lumileds uses about the same format for their datasheets so you can see what the usual Vf of a red rebel emitter is at 350mA.

Finally, you could use a 500mA version of the MicroPuck driver for the white XP-G emitter. If your heatsink does not get too hot at 350mA (0.5W of waste heat), you could see how it fares at 500mA (I calculated 0.80W of waste heat at this level). There is a 400mA driver as well and they all cost the same if you get them at LEDSupply. At 350mA, the R5 XP-G should output around 140lm at the emitter, but at 500mA, the XP-G should output around 200lm at the emitter! Just some additional food for thought...

I look forward to see how this goes. I have a big and bulky rotary switch but not any lights that utilize multiple colors of LEDs, so its still sitting in a box. Good luck with your trials and do not forget we can help you in nearly any aspect of this mod.


Cheers,
Tony

 

[Gryloc]

Hey there. I hate to be the bumper, but how is this project progressing? I look forward to updates.

 

[Balefire]

Still looking for a used Sidewinder to use as a host - unless I get really desperate I'd rather not buy a brand new one and tear it apart instantly. Your post was awfully helpful though, and I think I'm going to do away with the 5mm Red and White LEDs as per your suggestion.

 

[Viper715]

I'm interested if there are any updates on your project here. Very interesting stuff indeed. I had a Streamlight Sidewinder Compact that I did a review on some time ago, I has plans for some changes to it but lost it almost a year ago down in Fort Lenard Wood Missouri down at the ranges so never got around to the mods I wanted. I wasn't going to do anything as grand as yours but I wanted to swap the white LED for a XP-E or G and I wanted to change the reflector to a mop reflector. I wanted to swap out the IR for a green the blue for a UV and replace the red with a better quality LED maybe a red XPE if it would fit or just a better 5mm. I have a new compact on the way now after all this time and know I will still have the same dislikes that I had before but the form and function of this light have not competition really. So I would love to hear if you continued with this project or not and what results you have had. Thanks.

 

[sb_pete]

Anything ever come of this? I am interested in modding one myself now and am curious if this project ever got off the ground.