Small powerful Headlamp - 1xXML2, 1x18650 li-ion

[sirpetr]

Hi folks, I am starting this thread about prototyping of a new powerful and lightweight headlamp. Its nearly exactly 1 year after introducing Lucifer headlamp. This new headlamp is smaller and lighter than previous model and has greater supply voltage flexibility as it can be used with one 18650 battery, two or a pack of four. Its meant for orienteering runners, adventurers or for mtb bikers as a superior helmet light. It should meet following specification:

Specification:


Body: cnc milled aluminium aircraft alloy hard anodized
Led: CREE XP-L, 5000K
Optics: TIR 16°
Battery: 1x18650 Panasonic 3400mAh unprotected (battery container is openable and has got protection circuit),
Electronics: our own buck converter made of discrete components and driven by Atmel 8-bit MCU with efficiancy up to 95%, has got temperature protection, overdischarge protection and protection against opposite polarity
Modes: 5 + blink
Lumens: 25 – 850lm (max. mode is not time limited)
Runtimes: 85 – 1 hour
Weight: 150gr.
Waterproofness: IPX-8rating (1m submersion)




Overall its very tiny package so there is nearly no space for electronics, switch and optics. Also waterproofness could be little hard. I would like to have the front cover made injenction moulded from ABS plastics but it could have some flex in it not to press o-ring hard enough to seal it perfectly. If if will not work, then I will made them from aluminium as well.


Here are some pictures of the first design model, hope you like it. I think about adding little more cooling ribs, but I will decide after I got real working headlamp in a hand a test it in real conditions.


Electronics is my own electronics which I developed for regular Lucifer headlamp but with decent changes as it was originally made for 2 LEDs and also 2 battery cells in series. Now it should handle both 1-cell and 2-cell li-ion batterypacks. The main difference is faster PWM with higher resolution. Now its 62Khz with 10-bit resolution because of higher step down factor. Otherwise steps would be very high and noticeble. Faster clock should help me get there smaller inductor and leave place for decent 5x5mm switch.


Battery container for 1 li-ion 18650 cell is basically tube with some milling and threading. Im curious how this will work as I dont have any lathe, only a cnc mill – which is not best choice for this kind of things. Sealing will be done with O-rings as any other flashlight out there.



Design:

Weight 18.34gr
Weight 8.55gr
Crosssection of battery container with battery, protection circuit and springs inside

 

[sirpetr]

Aluminium arrived and we started machining. First come both caps of battery container. For both of them I need to make custom fixtures.

Cap with a hole for a cable gland was easy, its has got a hole where you mount a screw. I made similar thing few times before so I didnt expect any troubles with it. It went smooth and after a day of machining I got 14 pieces, 2 of them made with crossection by a mistake.
Thread inside is milled with a 4-flute tiny threadmill tool. Im little afraid about the proper size of the thread as it will get bigger with anodizing process. Im allso thinking about sandblasting all these pieces as it could give them better finish.

Cap without hole was little harder. I made 10 of them from one side a separete them on bandsaw. Then I made fixture plate for 5 pieces with thread. Caps were screwed on this fixture and clamped with a sleeve. Otherwise caps could be unscrewe by machining forces.

 

[sirpetr]

For the main part of batterypack container we bought aluminium tube 19/22mm wide. So the side is 1.5mm thick and one typical 18650 li-ion cell fits there nicely, even protected one (which has got a bit higher diameter than unprotected).


We have to machine them 2 at once in vise so they will not loosen and come out of vise. We do first top side and them turn them over and machine second side. Its crucial not to tighten them in second operation so much, so thin tube will not deform. Tube is almost fully sunk in V-block jaw and still vibrates little but. Its not perfect but quite acceptable. When you pull little more of it outside vise, tool starts to vibrate a lot. Thread is milled with a threadmill which is bautiful carbide tool with 4 teeths.


We think over machining our own high jaws with profile for these rounded parts so we dont deform them anyway.


We also tried sandblasting on few parts. Maybe its not visible on photos right now but I think it will be large difference in final look after they came back with black anodizing finish.

 

[Tixx]

Very cool!

 

[sirpetr]

Some new pictures, I am working on it hard. Headlamp body is completed. I wasnt succesful for first attempt because I drilled through the whole body when I was doing mounting holes. But second time I got it right.

 

[Tixx]

Coming out very nice!

 

[KuanR]

Surprised I didn't see this before, very nice indeed!

 

[gunga]

Great job. Any chance of lower modes than 20 lumens.

 

[Tixx]

Great job. Any chance of lower modes than 20 lumens.

That would be a good idea since it seems early in the game. 0.5 lumen is usually a good place to start.

 

[sirpetr]

Size and weight comparison to our regular Lucifer body. Difference only in aluminium body is 10gr., but in the end it will be much higher. Target weight 160gr including all is achievable.


Third pic is tube with somekind of stainless steel finish. Sanded version unfortunately doesnt look so good (see on previous images).


On few other pictures is driver. PCB is being made and come to us next week. For these prototypes we will solder and place components ourselves. Its switching buck converter and operates from 2.5V to 9V, so it can use both 1-cell and 2-cell li-ion batterypacks.

 

[sirpetr]

Tixx, KuanR: thanks.
gunga: something within 10-20 lumens will be the least light output. Unfortunately it couldnt be lower beacuse the sense resistor is very small and microcontroller wouldnt be able to find appropriate and repeatable level everytime it turns on. Is really needed mode with 0.5 lumens?

 

[DonX_Fi]

Hello
I would like also 0,5 lumen low low output. if possible ! When the USB power output will be available ? I will enter Finlands military refresher in 7th. December and I would like buy, if the USB output is ready before December.

 

[xcandrew]

For his stated target audience of outdoors moving sports, there is no need for really low output. I have the low on my Gemini Duo that I use for trail running/orienteering/skiing set at 20% or about 250 lumens, and I don't use it that low often. For reading in bed or that kind of thing, I just grab a cheap plastic low powered light without a separate battery pack.

 

[Tixx]

For his stated target audience of outdoors moving sports, there is no need for really low output. I have the low on my Gemini Duo that I use for trail running/orienteering/skiing set at 20% or about 250 lumens, and I don't use it that low often. For reading in bed or that kind of thing, I just grab a cheap plastic low powered light without a separate battery pack.

True.

 

[Tixx]

Any news to share? I think this is a cool project!

 

[sirpetr]

Hi, here is update. Parts came back from anodizing and threading fits together really nice. I put there three different finishes of a tube for comparison and I think clear winner is sandpaper finish which looks little bit like stainless steel.

I hand soldered electronics which was difficult due to DFN and other tiny packages but was still manageable. It took some time to check if connections are right and correct them with hot air if not. Circuit is mostly same as large headlamp circuit but there are special ICs which enable use of 1cell or 2cell li-ion batteries (2.5V-8.4V). MCU has got different code as well, it has to determine appropriate switching PWM for both cases. So far its working well, needs further testing though.

From mechanical side of view there are few changes that need to be made. Threading is smooth but entry of it needs more work. The second thing is design, I do not like it much and I want to do changes to make this headlamp pretty. Optics and LED will be centered, overall shape will be more chamfered. I start machining next week and new PCBs is already being made.

Spring is strong gold plated spring with resistance as low as 2-3 miliohms.

Front part is 3d printed from black ABS, it will be injection moulded. Screws will be allen screws.

 

[Tixx]

this looks great! Progress on this is really coming along.

 

[sirpetr]

Hi, here is long waited update. Why it took so long? Because the first concept was wrong and LED was not able to cool at that power. That meant, everything had to be redone from a scratch and that took some time. Also came season and there was no spare time for improvements and news.

And now only good news. Headlamp is fully functional, need only slight changes in driver uController program. It lights a lot and more than I mentioned previously because it has got better diode - XP-L HD, 5000K, bin V4, CRI typ. 75 and puts out 850 lumens (after heat and optic losses substraction). LED is - as always - directly copper soldered. Efficiency of electronics is between 90-95%, its little less than our current Lucifer M3 but sill very high value. Its not measured but based on measurements of one older nearly identical electronics. TIR optics has got 93% light transmittance and is very short so the whole headlamp is quite compact. Beam of the light is very pleasant without any artifacts with FWHM angle 16°.

Total weight (with included 1x18650 battery) is 150 grams. Head itself weights only 13 grams and has got massive cooling fins. Headlamp is very stable on head in every situation.

And now photos which tell more. On first one there is intermediate prototype which was much bigger and with large optics which was not needed for this diode. Button will be located in the front part as you see it now. Other photos show the last prototype model which will be nearly the same as production one. There is missing front optics holder, we are waiting for 3d prints. Front part will be made from plastics but will have ribs on the opposite side to be stronger. Optics will be attached with transparent UV curing glue.

Further details (light output, modes, runtimes) can be found on site:http://luciferlights.net/headlamp-lucifer-small which will be updated. This headlamp is mostly for runners, adventurers and tourists. Can be used for dry caving. Price is expected to be 92Euro without battery and charger. 18650 batteries can be used unprotected. Charging would be possible also from USB port with small accessory - no need to put the cell out of battery tube.

 

[mk2rocco]

Very nice looking light.

 

[Tixx]

Awesome!