Side switch, CR2 Keychain light, homebuilt.

Anglepoise

Flashlight Enthusiast
Joined
Nov 4, 2004
Messages
1,554
Location
Pacific Northwest
Any of you that have read my previous posts, know I am a bit anal when it comes to side switches on lights. I like them.....

sw2-8.jpg


With the availability of superb , state of the art, side switch drivers from member Georges80, I am amazed that we do not see more lights utilizing his system.
George ( Website) has over the years been quietly improving his excellent drivers. Today they incorporate a computer controlled UI (user interface) that is both simple, yet powerful and allows the end user to set and adjust parameters that are 'fixed' by other board makers. For example, the user can set and change at will the maximum current (ma) available to the LED,( no more sense resistors) as well as setting the low voltage cut out point, if re chargeable batteries will be used. Variable intensity, auto lock out, two different UI's, plus many other features. Believe me, as far as drivers go today, these are 'best of breed'.

sw2-3.jpg


I wanted to build a small keychain light. After seeing what fellow member 'tvodrd' achieved, ( see above, picture courtesy of Bernie ) I got motivated and set about coming up with a design. Studying the body of his 'Larry Light' it became obvious that the beauty is in the precision manufacture and quality control along with the fact that metal thickness has been kept to a minimum, thereby allowing a very compact and light weight package. I would have to select a very strong grade of Aluminum to come close to his dimensions. I knew that it would be difficult to make such a small light, incorporating a side switch. Also I had no idea if George would be keen on 'miniaturizing' one of his side switch drivers. Anyway I set the tentative design parameters at an outside diameter at ¾" and aimed for 2.25" in length.

centermodule.jpg



I would need one of George's drivers to be reduced in size to around 0.590". I had two worries. Could he do it and would he do it. I think George became intrigued with the idea and rose to the occasion.
Many emails later, lots of experimenting and we had a finished driver measuring 0.590" with micro switch incorporated……… and the joint collaboration was under way.

I thank George. For this project would not have been possible without his patience, input and unfaltering support.

stuff.jpg



Now I had the driver 'sorted', I set about the other items required.The body will be made from 7075 T6 Aluminum. Very strong,tough and hard. And it will handle wall thicknesses of 0.025" and thinner without collapsing. Just the material I need.


Moving back from the head, I selected a 16 mm 'O' ring set in the bezel. Resting against this is a UCL double coated glass window, custom ground to fit. Next a cut down McR18 reflector ( thanks Larry and Don for explaining how to do this correctly) resting firmly on a Lux III, epoxied to the heat sink in the middle section. Next is the custom, fully regulated, side switch driver set at 350 ma output. It has all the functioning features of it's larger brothers. An amazing accomplishment in miniaturization. I can't even see some of the components they are so small.

Battery power is a Cr2 primary cell, chosen for its size, good availability and long run time at 350 ma. And lastly a gold plated spring keeps the battery in contact. My original design incorporated sealing 'O' rings but even with 32 TPI threads, there just was not enough wall thickness behind the threads of the battery tube for the groove, even for a tiny cross section ring.

sw-2-4.jpg


A SS circlip in its own groove looks after attachment for a split ring and micro clip, and allows 'end standing' as well as complete removal if no attachment point is required.



How does it all come together. Well I am delighted with the overall finished light. The reflector puts out a center-weighted spot with more than adequate spill and quite frankly is 100% better than I expected. The overall length finished up at just over 2¼" with a diameter of ¾". Weight is 23 grams, 37 with battery.


sw2-7.jpg


As I write this in late October 2006, Cree madness is upon us. And yes……an XR-E or the new Seoul P4 will fit, but the reflector and head would need machining modifications.

'Anglepoise' Oct 2006.
 
Last edited:

TranquillityBase

Flashlight Enthusiast
Joined
Jun 12, 2005
Messages
3,741
Looks great David.....:goodjob: :clap:

That is quite an innovative clip attachment point too...:twothumbs

TB
 

TENMMIKE

Enlightened
Joined
Jan 6, 2006
Messages
668
Location
puyallup WA.
INFIDEL
Anglepoise said:
Any of you that have read my previous posts know I am a bit anal when it comes to side switches on lights.
For me this is the only place a switch should be and I dislike having to twist things with one hand or 'end click' with my tactical thumb.
'Anglepoise' Oct 2006.
nice work.
 

Paul6ppca

Flashlight Enthusiast
Joined
Jun 8, 2006
Messages
1,291
Location
RI
I agree with you on the side switch!That why one of my favorites is the lion cub. Are you goung to make more of these?Id be interested.

Nice job!

How does the user interface work?
 

Anglepoise

Flashlight Enthusiast
Joined
Nov 4, 2004
Messages
1,554
Location
Pacific Northwest
Paul6ppca said:
I agree with you on the side switch!That why one of my favorites is the lion cub. Are you goung to make more of these?Id be interested.

Nice job!

How does the user interface work?

George's drivers, including this one, gives the user a chose of 2 separate UI's. The user decides which of the two he would like and programs the Ucontroller himself. All George's drivers offer the same two UI's that are used in his **flex range of boards. Simple and intuitive.

This was an exercise to see if it was possible to reduce
this board/switch combination down in size ( below), give it full regulation, and then see if it could be wrapped in Aluminum to make a small light.
switchdriver-1.jpg
 
Top