simple high/low drop-in for Arc LS

Hi Folks,

<font color="red"> THIS THREAD IS NO LONGER JUST FOR TWISTY TAILCAPS! </font> Instructions for constructing high/low spring assembleis for Kroll switches may be found in this thread too

A newer design (type 2) is described here.

Do you have one of the LS series lights from ARC? Do you lust after the dual brightness mode of the Surefire L1 but prefer the size of the LS? Have I got a deal for YOU!

Here's a simple mod for the twisty cap AND the Tail Switch Packs.

CONCEPT; if you add 10-20 Ohms of resistance to the battery pack, the LS goes into moon mode (very dim). This will last a long time AND it's usable for up close work.

Why it works; The twisty pack is left partly unscrewed when off. You rotates it to turn it on. There's a little post in the bottom of the tailpack that makes contact with the bottom of the battery when it's turned on.

There's enough room between the bottom of the case and the bottom of the battery for a 1/4 watt resistor.

Execution (general); make a coil of the resistor leads and insulate them from each other with a springy material like foam two sided tape.

Execution; Wrap the leads of the resistor around a pencil so you end up with a spiral. Carefully cut a washer from two sided foam tape. Make the hole in the washer big enough to fit around the post in the battery case. Slide the washer between the two coils of wire to create the resistor pack. Make sure the wires don't touch each other. Drop the resistor pack over the post and insert battery.

USE: Unscrew the battery pack two turns for off. Tighten 1 turn for low and normal tightness for full.

The mod in place:


The resistor pack: (quick prototype, I had no wide tape /ubbthreads/images/graemlins/icon23.gif)


A very blurry side view (sorry, it wasn't worth it to re-shoot.)


I'm sure there are ways to improve this.

Daniel

(Moderator edit: changed subject line as asked)

Re: simple high/low mod for Arc LS twisty caps

I don't understand how the circuit is completed to allow the light to come on at all, let alone in full-mode.

Re: simple high/low mod for Arc LS twisty caps

gadget_lover,

That is beautiful! /ubbthreads/images/graemlins/thumbsup.gif I suspect that within a month or so, one of the "modders" out here will come up with a "drop-in" module. /ubbthreads/images/graemlins/grin.gif

Larry

Re: simple high/low mod for Arc LS twisty caps

[ QUOTE ]
this_is_nascar said:
I don't understand how the circuit is completed to allow the light to come on at all, let alone in full-mode.


[/ QUOTE ]

Because of the head-on shot into the base of the tailcap, it is hard to tell that the center contact pin is actually sitting on a raised base. The area around the raised base is where the resistor sits. One resistor lead (not visible in the picture) contacts the base. The other lead will come into contact with the cell's negative terminal. This added resistance puts the LS into moon mode. As the tailcap is tightened further, the center pin will make contact with the cell's negative terminal (as intended), shorting out the resistor and resulting in full brightness mode.

Clever mod, but I guess it assumes every tailcap has the same amount of space machined into it and that one uses a correctly sized resistor. (Physical size)

Re: simple high/low mod for Arc LS twisty caps

Wow, i tried it and it works.

Another why didn't I think of that!!! Thanks! Great mind.

Henry

Re: simple high/low mod for Arc LS twisty caps

Thanks for adding the explaination, EvilLithiumMan. Your clarification was very nicely done.

You are right about the physical dimensions. The center post has to be taller than the resistor. The wires plus tape have to be taller than the center post.

The current dropped by the resistor is very low, so 1/4 watt or 1/8 watt will work OK.

I find (on mine) that 10 ohms will give me about the same light as my Arc AA. 15 Ohms is almost exactly the same intensity as my Lumamax L1.

I'm glad you liked it, Henry (moraino). It was inspired by the Arc AAA's use of a foam donut to keep the battery away from the positive terminal. I'm hoping that, as Larry (tvodrd) said, there will be a properly made drop in available from Arc or one of our modders.

Daniel

Re: simple high/low mod for Arc LS twisty caps

Very clever. I'm impressed. It's one of those "so obvious that nobody thought of it" mods.

Re: simple high/low mod for Arc LS twisty caps

I hope everyone will try it. It works just like my home made two speed LS light using battery holder with two switches.

I used 10 ohms and just like what gadget lover said, the same light level as Arc AAA. I tried 20 ohms and it's a bit dark to my like. So I'll stay with 10 ohms and I'll use it more often for the night time because I now have a dimmer choice.

Henry

Re: simple high/low mod for Arc LS twisty caps

By the way, the 1/4 watt 10 ohm resistors are available from Radio Shack, 5 for 99 cents. Other values and smaller wattages are available from electronic supply shops.

A proper design would include a foam collar to hold the battery off the resistor pack when it's turned off.

Daniel

Re: simple high/low mod for Arc LS twisty caps

I am all in for the dropin !
bernhard

Re: simple high/low mod for Arc LS twisty caps

Me To.

Re: simple high/low mod for Arc LS twisty caps

Gadget Lover,

well done ! you make my day /ubbthreads/images/graemlins/wink.gif
Here is my version, i used a "Thermo-sheath" i do not now if the name is correct ( in italian is "guaina termo-restringente /ubbthreads/images/graemlins/grin.gif).
















And some beamshots, first level brightness


And full brightness , ARC-LS-Lux3T-@720mA-LP_Fraen .

Re: simple high/low mod for Arc LS twisty caps

[ QUOTE ]
Miciobigio said:
Gadget Lover,

well done ! you make my day /ubbthreads/images/graemlins/wink.gif
Here is my version, i used a "Thermo-sheath" i do not now if the name is correct ( in italian is "guaina termo-restringente /ubbthreads/images/graemlins/grin.gif).



[/ QUOTE ]

I believe the term you want is "heat shrink tubing", and it is available at any/every Radio Shack over here....

"Viva la Bella Donna..."

Re: simple high/low mod for Arc LS twisty caps

Will this work on my LSL?

Re: simple high/low mod for Arc LS twisty caps

Yes, it should work on all the ARC LS series without the tail switch. I'm trying to create a similar mod that will work with the tail switch.

Daniel.

Re: simple high/low mod for Arc LS twisty caps

I haven't got an ArcLS, but have to give credit where it's due, Excellent idea!

Re: simple high/low mod for Arc LS twisty caps

Daniel (gadget_lover),

I have been scratching my head to figure a way to do this with an SF L4. It would be nice to tone down the brightness every now and then.

So I wish you good luck on the mod you are considering, hoping that it's applicable in principle to the L4.

Paul

Re: simple high/low mod for Arc LS twisty caps

/ubbthreads/images/graemlins/ohgeez.gif Shoot, this is simple enough to do I might try it.
Thanks gadget lover
Mike

Re: simple high/low mod for Arc LS twisty caps

A drop-in mod for some lights (firefly?) could include a neg extender in the midddle to make axial room for the resister. I've been able to sometimes accomplish the same with very careful turn-on torque, resulting in increased battery contact resistance. (Fine pitch threads help!) This design concept needs to be exploited!

Larry

Re: simple high/low mod for Arc LS twisty caps

Muahhhhaaaaa!!! It's alive!!!!!
<font color="red"> Further research has shown that putting anything between the battery and the battery contacts is ill advised in the LS lights. The LS is machined to tight tolerances. Damage may happen if you tighten the battery pack with anything between the battery and the contacts. There is a spring replacement further down in this thread that is just as easy and is totally safe.</font>

I've just finshed a version that goes on the bezel end of the LS, between the positive terminal and the battery.

It works with a TSP (tail switch pack) as well as with a twisty and does not require any modifications to the light.

The end product is two metal disks connected by a resistor and held apart by the foam tape. The raw materials were purchased at the local Ace hardware store and at radio shack. It only took 20 minutes to create the drop-in.

The materials are....

1/64th inch thick brass stock, 1/2 inch wide
1/20th inch thick two sided foam tape
10 ohm resistor, 1/4 watt
nail polish

Tools:

center punch or nail
hammer
tin snips
scissors

Optional:

Solder and soldering gun

Real high tech, huh? /ubbthreads/images/graemlins/smile.gif

1) Use the tin snips to create two disks about 3/8 to 1/2 inch across. They don't have to be perfect.

2) Snip a little bit of brass from the side of both disks, making a flat spot for the resistor. Use the center punch to make a dimple in the center of one of the disks. We'll call the one with the dimple the top disk. My top disk looks like:


3) bend the resistor leads to a ninety degree angle close to the body of the resistor. Cut them to a length of about 1/4 to 3/8 inch.

4) * NOTE* The two sided tape should leave the center of the disk clear.
Set the resistor lead across the bottom disk. Put a piece of the two sided tape OVER it, securing it against the disk. Put a second piece of two sided tape under the other lead, insulating it from the bottom disk. It should look like this:


5) Place the top disk on top of the bottom disk. The two sided tape should keep it in place. The dimple should be
up (the bump should be towards the other disk). Together, they look like this:


6) Use a bit of your favorite insulator to make sure the edges can't short against the sides of the battery compartment. It helps if you smooth the edges with a file so there are no stress points. You can use nail polish, insulating lacquer, liquid tape, epoxy, etc. Remember, If it shorts to the side, the battery will do many bad things!!!!

Here it is in place on mine:



That's it. Pop it into your LS and use your favorite battery pack. When the pack is snug you should get a low beam because the current will flow through the resistor.

When you screw it down tighter the foam should compress, allowing the bump to touch the other disk, bypassing the resistor. Tada! High beam!

<font color="red"> DO NOT TIGHTEN PAST THE POINT WHERE IT LIGHTS!</font>

Daniel