Craftsman 2AA aluminum boosted conversion

We're just about to move - but before I packed up the shop I figured I do my first real intricate conversion. Sears sells a beautiful 2-AA cell aluminum flashlight. It comes in gold tone or black, is lifetime guaranteed, and costs about $8. The reason I chose it is because it has a nice push-on push off power switch, as well as the ability to focus the head. It's water tight with a tail cap for inserting the batteries. I figured there was j-u-s-t enough room to cram a voltage booster into the body.

Why torture myself? I love the compact size and balance of a 2-AA cell light, and this one looks like a nicely machined little light saber. I wanted aluminum over plastic, too.

I built a switching boost converter from a MAXIM MAX857 IC. This will produce a constant brightness light as the batteries die, with a low battery indicator. I can squeeze nearly every electron out of the batteries, as this chip runs down to a volt. I'm running about 40mA through a single white Nichia, and with the flashlight's reflector assembly, I'd say it's 3x my infinity, and gives my turquoise photon a real run. My measurements indicate 30-40 hours of run time which I'll test. The conversion went like this:
<UL TYPE=SQUARE><LI>Remove switch and incandescent lamp assembly.
<LI>Cut off lamp socket and hollow out an area for the boost circuit.
<LI>Look at tiny 1/4"x1/2" area for boost circuit and mutter why am I doing this?
<LI>Cut small PCB stock and hand draw circuit with sharpie pen on copper. Etch copper in radio shack etchant.
<LI>solder on components with tweezers
<LI>Grind down circuit board till it fits.
<LI>test circuit - it works!
<LI>stuff everything back into aluminum body.
[/list]


I have some pictures - not great ones - that I took with a cheapo digital camera. I'll try to get them up after I move.

Funny thing is - my wife who normally yawns at this stuff - took one look at it and said, "Can I have this one?" I never saw it coming!!

php_44: "I built a switching boost converter from a MAXIM MAX857 IC."

Can you please explain how you did this? Do you have a schematic or anything that you could post about it? Where did you get the chip? Is it a special chip or a standard IC? That sounds just like what I need to build for a mod that I'm working on and so I'm very interested to find out more about it. Thanks for any and all info.

(Arrgh! ignore the icon, I can't get rid of it)
Count me in. I want to build my brother an LED mod for father's day. Please, PCB art, photos, whatever you can post. You said you used tweezers, must be smt then? Did you use a microscope too?

Pricing
https://shop.maxim-ic.com/cgi-bin/Maxim.storefront/962520523/Product/View/MAX857CSA

Glad there's interest - I'd be happy to post details. By the way - does anyone know of a free web site I can post photos to to link to this topic? I'd like to post pictures.

If you download the data sheet from MAXIM using the web link someone posted - then just go to page 8. In the MAX857 scematic - which is very simple - I used a 22K ohm resistor for R1, and 10K for R2. I used a 6.5ohm resistor (two 15 ohm and a 50 ohm in parallel) at Vout connected to the LED then common ground (minus side of battery). For C1 & C2 I used a small 10uF ceramic cap, and think any smal tantalum or ceramic cap 10uF to 68uF would be fine. Naturally I chose the ones I had because they are truely tiny ones I scavenged from a discarded cordless phone (A great place to scarf surface mount parts). Same with D1, you could use a common (radio shack) 1N914 or 1n4148, or if you want top efficiency - a schottky diode (again scavenged). I used 38K ohm for r3 and 56K ohm for R4 - but you could just tie pin 5 to Vin (plus side of the battery and ignore the low battery function. The coil is a very efficient coiltronics 68uH part number DO3316-68 available from their web site. You can get a nice sample pack of surface mount resistors by mail from radio shack.

It took a while to gather the parts, but it is worth it! I was initially intimidated with surface mount - but it was not that bad. In fact making the pc board was a 100 times easier because there was no drilling and I could hand draw it without thinking of having to mirror image the artwork (through hole stuff has the etch traces on the bottom and surface mount on the top) so it was certainly less confusing.

As I siad - I'm in the middle of moving - but I'll try to post some artwork and pictures when we land again.

does anyone know of a free web site I can post photos to to link to this topic? I'd like to post pictures.

Dunno, but if anyone out there does, let us both know won`t you?

As you can tell, things aren`t the same with my web site`s host anymore.......

I've been using http://www.photopoint.com for image hosting for nearly a month now and it has worked fine for me and the best part is that, so far, it has been free. The only qualm that I have with it is that I can't use the Opera web browser www.opera.com to upload the pics (still don't know why yet, strange) so I have to use Netscrape Crashigator instead (I used 98lite to uninstall Internet Exploder over a year ago and have never looked back). Other than that it has been good so far. I'm anxious to see those pics that you mentioned. Sounds very interesting.

I believe Photopoint charge for their service now, unless you only want 10 pics which I would soon use up. Plus despite now charging for the service, they still adorn your pictures with their annoying advert. Small images like icons and smileys won`t work properly or at least they never used to- they end up in the middle of an enlarged white square so they can fit a Photopoint banner on it. I used to use them (long before discovering this board) but soon got tired of their banners.

I can still link to pictures on my Tripod server here but I have to make a web page for them to go on, simply giving the address of the jpg pics doesn`t work- they block that too.

Actually I remembered that my ISP provides me a small amount of web space. I`ve never managed to get it to work but I never had the right ftp software until recently. I`ll see about making use of that web space- I believe hotlinking images works fine from there.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Chris M.:
does anyone know of a free web site I can post photos to to link to this topic? I'd like to post pictures.

Dunno, but if anyone out there does, let us both know won`t you?

As you can tell, things aren`t the same with my web site`s host anymore.......<HR></BLOCKQUOTE>

Yahoo. I have problems linking directly to pics, but linking to the albums page seems to work fine.

For example:

Gadget's Yahoo Album

Free, decent amount of space, no banners added to the pics.


single pic

Gadget,
I had difficulty with Yahoo pictures too, until I figured out how to get the direct URL of the desired picture. Here's how I did it:
1. Click on the thumbnail of the picture to show the full size version.
2. Right click anywhere on the image, select "properties". This will show the properties of the image including the URL.
3. HIghlight the URL inside its box- be sure to get the whole thing, since the URL is runs longer than the box itself. Just start at the top and let it scroll through to the end. Another way is to get the cursor blinking anywhere in the field and press control A- this selects "all".
4. Once it is highlighted, press control C. This copies the URL into memory. Then paste it into the image dialogue box when you're composing your post.
This works on a PC- not sure how to do it on a Mac.
Hope this helps somebody
Chet

On a Mac, contol click on the image to get a dialog box- select "open image in window". Then, once the image is displayed you can copy and paste the URL from the browser address bar.
Chet

Good idea in principle.....only it doesn`t work. At least not for me. I set up a Yahoo Photos account, and tried that very thing to post the picture here instead of having to post a link to the photo album. Yahoo have something in place that prevents direct hotlinking (only allowing the image to show up on the photo album web page) I think, cos when I tried pasting the URL of the image in the address bar to see if it came up on its own, it said I didn`t have permission or something. And I tried it in a test post (not here though) and it came up broken, just like all my Tripod ones.

http://us.f1.yahoofs.com/users/d99a1445/bc/Hybrid+Lantern/Black+ring+came+with+light.JPG?bcE.DL7A40kHACxm

See if this works....

Chet, great tip! It finally worked.
Well, kind of worked.

I still have to right-click the "dead link" and "Show picture". Then it comes up. Wierd.

Chris, try it exactly as Chet describes. I had done the "Copy Shortcut" method before, and that doesn't work. Chet's method did, as long as you do the "Show picture" thing above.

Oops Craig. I deleted the post. Doh!

Totally off topic now.

I started a new topic about Pic posting. May have a good, free site to host pics fom.

Check out the test topic to see if the pics load for you.
http://www.candlepowerforums.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=28&t=000046