I have a few small keychain/camp light, recently I picked up an interesting small light: Pak-Lite https://9voltlight.com/
because I have quite a few 9v batteris retired of from smoke detectors. I quite like this little light.
I’m starting to wonder if there is a similar option for AA and AAA batteries. I’m sure you all have some half dead ones around.
After some dig, no, there is none, so here is my approach (with a 3d printer, some experience with soldering, I think I can make it happen):
1 AA
Twist to turn on (I hope so image above is self-explanatory)
Friction fit - with TPU filament, hard rubberish texture
Nichia NSPW500GS-K1 5mm LED
ZXSC380 or PR4402 drive
How do you feel about this?
PS. I’m really hoping can get some advice from you about the led and drive, the 5mm and drive chip is quite old, but I didn’t find anything more suitable.
I hope to get something more efficient, in order to run longer.
Also trying to keep the borad very easy and cheap to make.
Back then I ordered some drivers from gchart, but those would be used with 3V LEDs, not these LEDs.
Sofirn made the C01 with 5mm Leds, using AAA batteries, with the same kind of purpose but with a different host.
Maybe this is helpful:
Looks like the sort of light that would benefit from a joule thief circuit.
I looked into making something similar a while back with a blinking locator LED for marking tentpegs/guylines when car camping but ran into difficulties making a flashing circuit…
I’m not sure how reliable the connection would be. Does a light like this even need a switch?
Hi MascaratumB, thank you very for the info, yes those links r very helpful!
About the LED
The 1st reason I picked 5mm just because it come with lens, so no need for reflector I guess
(I do prefer COB because I’m going to use a heat plate to solder, so if every thing is SMD that will be easier)
The 2nd reason is to make it run for long hours, . I heard 5mms run longer than COB, but not sure.(I can not figer out the 5mm led’s watt per hour)
also if it could have good CRI that will be a plus.
On digikey the 5mm and COB are under different category, made it very difficult to compare. especially I am not very familiar with LED chips.
So the ideal LED is:
No need for reflector
24h run time on 1 AA（40mh 3v I guess?）
Good lumen per watt
Good CRI
Just want to ask if you have any suggestions about the LED chip? Thanks!
Hum, I would not be the best person to inform you about the driver for this flashlight.
As I mentioned, when I was looking for a “joule thief” flashlight (the link you posted above) I dealt with member @gchart and he built some adequate drivers for my need, although not for 5mm LEDs.
Maybe he can help you with that. Or maybe you can contact Sofirn ( @Barry0892 ) and check if they have some spare drivers from their C01 flashlights.
Otherwise, I am not aware of drivers being sold for those leds.
Similar to the ZXSC380 that was mentioned, the ZXLD381 is cheap and easy to implement. While not designed for a 5mm LED specifically, there’s no reason why you couldn’t solder one to the pads on this driver board. I have some testing details about that here. Heck, I think I still have some of these boards and components sitting around. If so, they wouldn’t take much time at all to build some up. And as simple as a design as this is, I could throw together a new driver that’s meant for a 5mm LED and a AA battery.
As far as some good 5mm LEDs go, you could try and find some Yuji’s or see if any of these are available.
BTW, neat concept with the 3D printed twist housing!
If you can get one, the L3 Illumination L10 is a good minimalist AA light. It’s about as small as an AA light can get, and runs AA cells down pretty low. Plus, it has a really nice beam and good runtime and a simple but effective interface… either low/med/high or moon/low/med/high, in that order. The low mode runs over 24h per charge, from what I recall, and is what I almost always use. It was built in both XP-G2 and Nichia 219B flavors, and I really like the 219B one.
But that’s no fun, because it already exists… you wouldn’t get to build it.
Hi gchart, thanks for the info! the post you linked are great, actually I saw them before I posted here. they are one of the reasons why I started this little project thanks for your informitive sharing again.
I just ordered some ZXLD381, 15uh inductor，and some 5mm leds. hopefuly everything can go together nicely.
Just wondering by any chance if you know the Sofirn C01’s drive setup? I couldn’t find it anywhere.
Oh I see! Sorry, I thought you were looking for the driver
Well, but gchart has replied and mentioned the Yuji Leds, which are also used in the 2nd version of the C01.
I hope you find them and manage to build that flashlight! Seems a nice concept
I have a super lightweight plastic AA 2 mode w/ two 5 mm hi cri and a red 5 mm. Headlamp . It vampires all old alkalines . One of my favorite el cheapo lights only thing I’d change is I’d drop the red for a true two mode 1 led or 3 . Right now it runs at about 8 lumens on two 5mm Yujis . I’d like a second mode running one at about a lumen or less .
There is great joy in taking out the last of a cell known for trying to take out your electronics . Nothing will ever leak in something you use often . It’s when you put it in the drawer and forget it …
I tend to avoid alkaline.
In regular used devices like my goto digital multimeter I use NiMH. In the once a year DMMs I have 1.5V Lithiums.
They don’t leak, they work well in cold weather. Pricy, but IMHO worth for DMM or the emergency backup Lamp in the car. You buy a car fit it with a lamp and Li, when you sell the car the lamp still works.
Mostly from Energizer, but other brands will do
Energizer L91 is AA
Energizer L92 is AAA
The standard shelf life was 10 years, like CR123, now they are claiming 25 years
thanks for your informitive sharing again.
Yarrr, matey! Yer nards ain’t s’pose t’ leak! Stop puttin’ bat’ries in 'em!