Can anyone step up for an AA/2AA only BLF budget flashlight?

Hey calipsoii, thanks for sharing the teaser with us, now how about some details and a sales thread? :wink:

Some things I’d like to know:

1) With your circuit design, is the 420mA output the most that a single Eneloop can do, or is it set at that level for safety, or efficiency, or parts are cheap, or what?

2) You said maybe 2xAA or 1xCR123A might do higher current. Any way we could get testing done on that? If you don’t have the time or the means to test, could you send a sample to one of the guys here that do testing, like djozz?

3) Will you be selling this driver? And, if so, when, where, and how much?

4) Is the design open? Will you be sharing your board layout? Could someone here legally make PCB changes in order to improve the design, make different sized boards, or change components?

Wait, is that 2 different drivers? or one 2-sided driver without a spring contact?

Two-sided: with current control on all levels, an Attiny85 and a torroid there's not an option for a 14mm one-sided board.

I just read some parts of the build thread. Thanks to djozz for the link! I’m really interested in this driver!

Great looking driver you created there calipsoii. Checked out your build log on CPF. You really do some first class work.

I don't have time to look at the data sheet for the Linear's LTC352 today. Did you consider the PAM2803 when choosing a boost converter? Supposed to be designed for a 1 amp load.

PAM2803 is too large for a 14mm board. The boost converter stats aren’t important anyways since it’s only jumpstarting the ATtiny which then takes over switching. The electrical path components are all rated to 3A (well, the sense resistor is only rated to 0.25W) so this circuit has a higher ripple ceiling than one using the PAM2803.

I scavenged an AA boost driver from a cheap zoomie and it uses a ME2180 DC-DC regulated output voltage chip that might be of interest.

A picture of the driver can be found in my build post.

The datasheet can be found here.

Here is the website for the company that makes this chip.
http://microne.com.cn

Many of their step-up DC-DC converters look suitable for an LED driver because they only need two external parts: an inductor and a capacitor. Since these are voltage regulators and not current regulators like the PAM2803, they are better suited to power the ATtiny.

I have a hard time finding a source for the boost driver that uses the ME2180. Has anyone else come across a similar driver?

1) The 4R7 inductor is probably determining peak current. A 2R2 (used on most boost boards) would likely give higher current at the cost of higher ripple. ~350-400mA was always the target: decent brightness with a decent runtime. If I need brighter I'll reach for a li-ion light. :)

2) Did a couple tests! This is through 15" long 22awg alligator leads connected to the battery with neodymium magnets so total circuit resistance is extremely high. Board was floating in air with no heatsinking and overheated before I could finish the 2x Eneloop run.

3) and 4) are undecided :)

They’ve all left for reasons of their own. There’s a tendency to keep asking more and more of those few who can to develop drivers and such for the rest of us. If I had to guess I would put it down to burn out and suggest we give thanks for what they have left us and move on.

Some of the early driver designs centered around finding ways to use the attiny13A micro controller piggybacked onto an existing board since there was an already growing group of software savvy engineers and hobbyists that were fooling with it and it was in common use on certain linear drivers. Some designs began with minor modifications to allow two cell (6V) input to an ostensibly one cell driver to allow it to control a 6V led, specifically the MTG. Figuring out how to piggyback the attiny13A onto an FET based driver opened up another avenue of designs and during all of this more and more drivers and other items were being designed using Eagle CAD software and shared on the forum. Some boards were designed to use pic platform mcu’s but the vast majority was based on the 13A. It is now being supplanted by it’s more powerful cousins in the newest work and smaller cousin the mmu on the smaller board designs but for now remains the most commonly used mcu for DIY. Hope that answered your question to some extent.

Wow! That 2x Eneloop line! Let me know if 3) and/or 4) become decided. :wink:

A lot of people here would just use a Cree XM-L2 or Nichia 219C that could take the ripple. There are advantages to standard liquor store cell voltage.




You got me bro.. Where do we send the cash? Seriously I am interested if you start selling them.


The program ability of an AA driver is a milestone in my book. Looks to me like based on the results in your graph we might expect 450+ma from a single NIMH AA.. I think my tank 007 about 700ma on one.

Thanks a million for sharing. You just poured buckets into my barrel of hope!

Anyone remember the old programmable k106 akoray from kaidomain? Those were three mode programmable lights. Buck/boost? running either AA or 14500. This project kind of reminds me of those lights. Too bad the the drivers went bad on the ones I had.

My little input: I support the idea of not asking all tools to do the exact same function, if an AA BLF light has to be made I would find appropriate to make something a bit different that would stand out. We can already buy at quite good prices premium quality AA lights that do huge lumen numbers on AA and 14500, what about considering a different single AA host architecture than the usual tube?

Something like this:

This one appears to be out of production ;)!

I would go for a light that style for sure. Especially if there was a head band option with it.

I agree it would be nice to see a GB take a step sideways(pun intended).

Here are a couple I have seen like that.
http://www.aliexpress.com/item/Supply-Genuine-UltraFire-H2-flashlight/1474052819.html

Here are some, but some have no band with them.
http://www.aliexpress.com/promotion/promotion_trustfire-z2-promotion.html



I greatly prefer the look of the Ultrafire one vs the Trustfire.

Or this:

I have the CR123a powered Z1, and its main fault is driver inefficiency in high mode.
This doesn’t come with a head band, but the clip can be used to shine it forward from a pocket or belt.