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Single XML focusable Aspheric light with wireless bar switch

41K views 173 replies 17 participants last post by  mattthemuppet 
#1 · (Edited)
Things have been a little quiet in the shed of late so I though it was about time I fired up the lathe and mill again and built something new so I've spent the afternoon on the couch designing a focusable aspheric helmet light.

What I came up with is another aspheric light that can focus from 12.5mm all the way down to 5.5mm (distance from aspheric lens to the top of the led heatsink). This will give a tight spot beam just projecting the die image to a nice wide flood beam.

The idea is that as a helmet light I will be able to adjust the beam angle on the fly to suit the trail conditions and speed. I am tossing up fitting a detent ball and spring so the I can feel a positive click each 1/2 - 1 mm of movement to make it easier to get the beam right by counting the clicks. I have also added an anti rotation pin so the side always stay in line.

Driver wise I'm going to use another Lflex and power it from a 1S2P li-ion pack since that combo worked so well with my last build.

The weight of the complete light minus the battery should be around 95 grams.

Since I haven't made any chips yet here are some cad renders of the light. This one is Octagonal since I have some of that bar stock left over but future lights will be either hexagonal or round.



Housing extended to give a tight spot


Housing retracted to give a flood beam
 
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#4 ·
Brad72, how will you implement the wireless remote?

Will it cause any interference or will any of the other electronics on the bike interfere with it?

Will this be bluetooth or something else? What will power the remote that sits on the handlebar?

Brilliant idea. I always thought that wireless control for a helmet light would be perfect. Can't wait to see the finished product.
 
#6 · (Edited)
Brad72, how will you implement the wireless remote?

Will it cause any interference or will any of the other electronics on the bike interfere with it?

Will this be bluetooth or something else? What will power the remote that sits on the handlebar?

Brilliant idea. I always thought that wireless control for a helmet light would be perfect. Can't wait to see the finished product.
At present I am planning on using an FM signal to operate the remote module but I am still waiting for them to arrive so it is a little up in the air. The modules I have found use a 12v supply so I am going to need to modify the circuit to run of 3 volts and also find micro relay to provide the NO contact to operate the Lfex driver

I have looked in to bluetooth as that would be ideal but I am going to need to do much more research as this is something I have no idea of how to actually achieve the end result. I like reading stuff though so this will be quite an enjoyable, if not frustrating challenge.

As for interference well that is going to be suck and see but hopefully it will be ok

.
 
#7 · (Edited)
As Barney would say from How I Met Your Mother, "challenge accepted":)

I know how to do it but how to integrate it into the light and keep everything weather proof might be a bit of a stumbling block. There is also the issue of allowing for metal expansion when everything heats up. May be I should say, challenge accepted but this could take a while.:eek:

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#9 ·
This is going to be a complex housing to build and tough to keep the weight down. If anyone can do it though you're the one.

Are you going to use thermal grease between the LED body and the lens body? Seems to me there will have to be to get decent transfer to the fins.
The weight should come at about 100 grams without the battery but your right it is going to be a pr#ck to machine, especially the threaded sections. Maybe I should cnc my lathe 1st.:D

The heat transfer is something I have been contemplating also so I'm glad you mentioned it also. I am going to need a pretty tight fit on the sliding body if I want any efficient heat transfer. I might need to modify the housing so the bulk of the fins are are around the led body making the sliding body holding the aspheric a little smaller, or just make it and see how it turns out.

If I only ran it at 1A then it would not be a problem but since we all like a light cannon on our heads it will need to handle the heat from 2.8 amps.

Man, to think 15 years ago we were happy with the light output from a cateye light run off 2 C cells. and a 3v bulb, relying more on our night vission:eek:

.
 
#21 ·
I am really liking this idea and just though up a possible solution..

Why not just butcher a tiny RC car? Or buy a rx unit from hobby king. It would give you a 2 or more channel controller 1 channel for light level/on off and another for the lens zoom. Small simple cheap parts to be had. Many are even 2.4ghz. Even included the necessary stuff for controlling a stepper motor, servo or brush less motor properly. A lot of them also have a battery voltage to 5v converter built in. You could even use a servo for adjusting the focus. lots of RC servos only weight 1-5 grams. You could even get a tellimetry enabled unit and have the battery level displayed on the handle bar remote. Of course many of the TX units are bulky and you would have to come up with something small and low powered.
 
#3 ·
Toaster, here is picture showing the main parts exploded. There are 4 x 0-rings in the light. 1 seals the front bezel to the the aspheric lens, 1 seals the front bezel to the sliding body, 1 o-ring seals the sliding body to the led heatsink and the last seals the rear cap where the Lflex driver will be located.

You can also see the anti rotation pin on the led body and the corresponding slot on the sliding body

One thing I forgot to mention is that I am going to try and make this light remote control so the power and mode selection switch can be located on the handlebars via a wireless switch to save fumbling around on my helmet.

 
#10 ·
Up goes the bar again...!

Looking good Brad - I had a crack at wireless remote (details here) but it was very rough compared to that design.

Is that the sort of module you were thinking of using? If so they work a treat but I found I had to use a small aerial wire as the transmitter was very low powered.
 
#11 ·
Great light Tanner. I hadn't seen your wireless modules but they look pretty good and might be better as the receiver voltage is already 5 volts.

The ones I am looking at are still 433mhz but I have the options of 1,2 or 4 channel, which would be great if I am able to motorize the focusing of the aspheric.

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#12 ·
jeez louise, way to go making us look bad Brad :) It'll be a stunning light though, once it's done. I think just the adjustable throw plus the wireless remote would be enough, but wirelessly adjustable throw would be the icing on the cake!

I agree with others though, all that finning isn't going to do diddly without a gap between the sliding and non sliding parts that'll be so tight as to make it hard to adjust. Is there any way to make the finned part bigger? E.g to make the anti-rotation key actually part of the housing and fin that, so you have the sliding part a sort of "hood". The other approach would be to have the adjustment mechanism internal, but that might be a smidge too complicated :)
 
#13 · (Edited)
Thanks for your input Matt. I certainly agree with your comments about heat transfer if pushing high amps. I have started to design another housing so i might use this current design with an xpg or xte and run at a maximum of 1.5A.

I have designed the mechanical focus unit but just need to find a small geared motor. I was going to use a cd laser drive but these are a stepper so i need a special drive circuit which is not doable.
So the challenge is to find a small dc 3v geared motor.

Think i have created a monster but fun none the less, but I might change my tune when it comes time to machine the fiddly little thing
 
#17 ·
Was bored this evening so I mocked up a more heat efficient housing with a motorised focus mechanism. I still need to source the 3v motor to drive the focus ring and machine a prototype to ensure there isn't too much friction between the drive pin and the slot it runs in. The 3rd part from the left that looks like a top hat has a slot in it that guides the stainless pin on the focus ring holding the aspheric lens. The part to the right of the aspheric has a straight slot in that captures the stainless pin, and when it is rotated the pin follows the contour of the slot in the top hat looking part, moving the aspheric in and out.

My other option is to use a small lead screw from a floppy disc drive mounted to a geared motor, mount the aspheric to a cradle and and move it in and out that way. Less parts than the housing I have mocked up but we will have to see.

Here is the first motorised mock up, minus the motor and gear.

 
#20 ·
Great idea Jay but Ii think the modern camera's use a stepper motor so i would need to find an alternative motor. I do have an old camera at home though so i might pull it apart and have a look.

I think the lead screw and craddle method might be the easiest thinking about it over night as there is bugger all machining and components. The old floppy drives are also really easy to get my hands on.

Time to mock up another design i think
 
#23 · (Edited)
Thanks for the the suggestions guys. It's going to be hard to focus on work stuff today with all these ideas buzzing around.

I am looking at a 2 channel control board from a micro helicopter as we speak but it is IR so not suitable unfortunately. I found a micro 3v geared motor outputting 140rpm this morning very similar the the one in your link Toaster on fleabay so that should be perfect to drive the focus so I will order that today.

Again thanks for all the input guys.
 
#25 ·
Well I haven't done to much more on the housing side of things but have settled on a 3mm diameter lead screw with a 1.8mm pitch to drive the aspheric (mounted on a slide) back and forth driven from a 3v DC motor so I can still use a single cell supply. Since the single cell puts out 4.2v when fully charge I am going to fit a 3v voltage regulator to keep the motor speed constant.

I have ordered a 4ch RF receiver and transmitter to deal with driver mode changes and operate the dc motor in forward and reverse. The Australian module from RS Components is not as cheap as I would like but for testing it will do fine. There is a company in the states selling receiver/transmitter kits nice and cheap but the UPS shipping makes them far to expensive ($20 for the parts, $90 for shipping) so I am looking at another supplier. This is the USA module 4Ch RF Remote Control System featuring KeeLoq Code Hopping

I have ordered 2 SMT NO tactile switch's which will act as a limit switch's, cutting power to the motor when full retraction or extension of the lens has been reached. Therefore, if fully extended, the motor will only be able to be retracted until the extended switch state has changed and vice versa.

I also have some SMT reed relays in case the transistors are not capable of the motor current, but I will have to make a small pcb to mount them to as it could get a bit messy otherwise.

So all in all it is getting a little complicated but nothing like a challenge, or it might be mid life crisis as I turn 40 on Sunday. Now, just to design an integrated driver and multi channel RF module in one.:eek:
 
#26 ·
Now, just to design an integrated driver and multi channel RF module in one.:eek:
If your going to go to that much trouble why not also incorporate a servo or stepper motor controller negating the need for the stop switches. And while your at it make both communications modules 2 way so the handle bar remote will show the zoom point, light level and, battery status. In case that is not enough pre programmed zoom and light level steps would be nice. And can't that handle bar remote also warn if the light head is getting hot. And while your at at can it allow the user to program the unit with the remote. You know to create your own light level and zoom pre settings and battery voltage levels. Oh yea and make the whole board out of a thermally enhanced material and have the XML soldered to it like a quazzle lux-rc light engine.

That was meant to be toung and cheek, I am already so impresses that I would not be surprised if implementing all that was doable. Keep up the good work, this design when built will once again push the boundaries.

This project of yours should also make me less lazy and perhaps I will finally get around to adding wireless to my helmet light like I have talked about in that thread.
 
#29 ·
I made a start on a manual focus aspheric housing today. Machining wise it is pretty easy as 3/4 of it is done on the lathe so much faster than a mill built light.

I have opted for this housing to have a remote driver or an all in one driver so I have cut heat sink grooves in the rear of the housing to get the heat away. I also tried a 125mm carbide tipped saw blade to cut the grooves in the rear of the housing and it worked really well. Took about 2 minutes per 12mm slot deep groove vs about 15+ minutes using a slot drill.

Here's a couple of picks of the machining side of things:

Led body in the lathe


Aspheric holder getting some grooves turned up


Cutting slots in the led housing using the 125mm carbide saw blade in a 3MT arbor I made up
 
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