Turn a regular flashlight into a powerful LED torch that will run for years
Posted 08.11.2008 at 11:09 am
27 Comments
The code for your Freeduino sketch:
/* Charge Pump ** 13 June 2008 ** PopSci.com ** Freeduino Pin ** Pin D3 = output */ // Freeduino Pin D3 for output int pumpPin = 3; void setup() { pinMode(pumpPin, OUTPUT); } void loop() { // Set Pin D3 for full output digitalWrite(pumpPin, HIGH); // Pause for 7 microseconds delayMicroseconds(7); // Turn Pin D3 OFF digitalWrite(pumpPin, LOW); }
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Could you be a little more specific about the downloading and burning of the charge pump code (for us not-so-bright flashlight builders)?
A schematic of the board layout would be helpful.
Also, I could not find your reference to th G.Y.Xu article.
What's the cost comparison? A thirty dollar flashlight is still a bit much for my budget, however I might be willing to make the sacrifice if I knew a similar LED product was worth, say, $100.
AARGH! After two attempts! Posts with even plain-text url's in them are being held for review as possible spam!
So, to find the G. Y. Xu article you can google search for "February 2008 nuts and volts charge pump" and follow the first two links to the two pages of the article.
-Adam
P.S. Flagging posts with links for review is a good idea, but I think it makes more sense to let them show up while they're waiting to be reviewed, then delete them later if the do turn out to be spam!
Your "instructions" are frustratingly vague.
I assume the LEDs are used in parallel, and the AA batteries in series. But in the absence of any kind of diagram (which I expected to be posted online, since it wasn't in the printed article), I've no idea how to wire the charge-pump circuit, or the Freeduino unit, or how to download the code into the Freeduino (some kind of USB hookup?).
I know your How 2.0 articles are heads-up "teasers" to get the reader on-line, but I'm disappointed to find the on-line version of the article to offer no illumination (!).
(I've been an intermittent subscriber since the early 50s.)
This is the first "How 2.0" article I've ever followed up on.
Pretty lame Prochnow.
You took Xu's article on using a MCU/charge pump which was propeller-head over-the-top (and stupid) and adapted a Freeduino? OMG! Just get an LED driver (like the "BuckPuck" DC-to-DC converters as cheap as $13) and be done with it.
You've got all these poor souls trying to figure how to get code into a microcontroller to step up voltages for a flashlight!! 2 hours for this project? Give me a break! Obviously standards have gotten pretty low since I used to write for these magazines.
lnwolf41
Was at Target store 2 days ago, Black & Decker has an 8 led worklight for $20. uses 3 aa battries.
One must be a subscriber to "Nuts & Volts" to obtain the article cited. That's not useful, as I don't want to give my email address to them.
I am not a geek. So pray tell what does all this mean and what am I suppose to do with it? I have ordered all the parts but as far as I can see all I will have is a handful of junk unless I can get some useful information and construction guideance. Can anyone help me?
altews@bellsouth.net
Wulfden, the source of the RBFK+ Freeduino/Arduino porcessor board will program the chip at no extra charge.
One thing funny though, the code shown has no delay at the bottom of the loop so it never really goes low again, it goes low but then is immediately set high ... is this a mistake?
Dave, let me know so I can setup the right program to bunr into the chips ...
Brian Riley - The Shoppe at Wulfden
Underhill Center, VT, USA
is there anyway you can use a charge pump circuit on an rc car to multiply its speed, and if so how.
please tell me!
thank you so much,
sergio
I found the XU article and realized that Dave's code as shown here on the website is correct and will work because his circuit is the second case with more than two LEDs where the off time is absolute minimal off time for the charge pump.
Any of the guys who ordered RBFK+'s from me before I put the "PopSci Special" link up may send the ATmega chip back to me with $1 to cover return postage and I will program it and send it back. Make sure you protect it by putting it back in the foam pad it came with or a piece of anti-static tube and pad it with bubble wrap or cardboard. Will turn it around within a day of receipt.
cheers ... Brian Riley - The Shoppe at Wulfden
I had a couple of emails on this matter and we seem to have resolved getting programmed chips everyone who bought RBFK+ kits .
I was looking over the parts list and realized that I carry 75% of the other parts for various products I handle. So, when I ordered from Mouser today, I added in the two parts I didn't have. By Friday I will be able to supply all the electronic parts for this kit, you will need to get perf board at Radio Shack and batteries and the light housing itself, wherever.
I plan to offer a basic RBFK+ kit with the superfluous parts stripped out, plus the LEDs, caps, diode, switching transistor, inductor for about $20 including USPS First Class Mail l(Priority shipping extra)l This will save you $3-5 in additional shipping from a second vendor.
Check my website later tonight for details, I need time to work the numbers and edit the webpage,
Brian Riley - The Shoppe at Wulfden
Do these components come in small enough sizes to convert a 2AA sized mag light using one battery, or two AAA's, or?
If any of you have finished your flashlight...
How does this compare to other LED flashlights? Is this just another LED flashlight, or does the charge-pump circuit make this one very special? How does it compare to the new one watt LED headlamps? Does it hurt the LEDs to run them at such a high voltage?
Not going to go into too much detail here, but using the Arduino or Freeduino for this project is serious overkill in terms of both cost and processing power. The 'duino platform (of which I am a big fan) is, although capable, intended for much more complex tasks. I recommend checking out the Arduino website if you are interested in beginning embedded systems. It's a very cool (open source!) project.
For the LED flashlight project...
If you look at the "code" to cut from the article and paste to your Freeduino, you'll see that it's just toggling a pin (turning on and off) every seven microseconds. This can be accomplished with a simple 555 timer IC in a circuit that is much simpler to assemble and much cheaper (about $3 vs. $15). Google "555 timer" and you'll find all sorts of resources to get started. It really is easier.
...and I agree with the above comments about the links. Both were "broken". the Geocities link is down and (though I am a subscriber) the Nuts&Volts link requires subscription/login.
Don't mean to be all trollish with my first post here, but you know how it goes,
-mlaargh.
You have to be careful when you look for the Nuts and Volts links. You must Google exactly this "Feb 2008 nuts and volts and charge pump" ... the 'and' between volts and charge pump turns out to be critical for some reason. You get the links to the actual article, without having to be a subscriber.
That said, I drew a schematic based on the original article and modiifed for Dave's project, and it on my website, the link is on the order page fr the PopSci project.
Brian Riley - The Shoppe at Wulfden
Re: LED Flashlight DIY Project
Most of the 16 previous comments say it all as well as the poor ratings indicated!
This project still could be salvaged if Mr Prochnow revises his instructional WEB page to include the suggested additions, corrections. I
Re: LED Flashlight DIY Project
Most of the 16 previous comments say it all as well as the poor ratings indicated!
This project still could be salvaged if Mr Prochnow revises his instructional WEB page to include the suggested additions, corrections. I
just tested
First of all, Ii want to thank all the people who have ordered the kit. That said, please bear with me as I struggle to get all the orders out. The first 25 kits will be in the mail this afternoon and the second 25 or so will go out Thursday morning. (I had to order more parts again yesterday, due in tomorrow). This project arrived at about the same time the Summer slump in my little business decided to end ... so things here are a bit hectic. I expect to be caught up and have a bit of a stock built up by Friday.
If any of you will be at the Boxboro (MA.) Hamfest near Boston on Saturday the 23rd, I will have an indoor selling spot and will have a small stock of kits with me plus my usual wares. Stop by and say hello.
Along the way I have been able to muck a bit with the kit. I have modified the Arduino bootloader so that the light comes on in under 3 seconds instead of 10 seconds. I built up the circuit a couple of times and took pix along the way. I started by breadboarding it and then did it with an actual flashlight unit. When I get done shipping the first batch this afternoon, I will post the pix to a webpage as well as incorporate them into a pdf manual with schematic , parts list and identification, etc. So keep an eye on my website.
I played with circuit some and experimented with what happens when you remove or bypass various components in the charge pump. The actions that simply shut it down aside, the most dramatic action was removing the 1 uF ceramic cap across the LED chain ... that reduced the LED intensity by more than half! The least dramatic, actually no effect at all, was removal of the 22 uF cap at the input to the inductor. It appears to simply steady/smooth the Vcc to the Arduino board.
Brian Riley
The Shoppe at Wulfden
Underhill Center, VT
Guys please--this "project" is turning into a giant cluster-f. Look up www.luxeonstar.com (no affiliation)as an example and click on LED drivers. You need one of those drivers, some batteries, and whatever LEDs you like. The site has sample circuits, even the killer LEDs that will put this flashlight to shame. The only reason for this project is an intellectual circle-jerk leading to The Shoppe at Wulfden getting your hard-earned money.
Once again, Prochnow gets the "Easy-Bake" half-baked award for lousy project of the year.
I'm not an electronics expert by any means, but this looked liked something practical I could do with my son. The problem I saw was that there are so many unanswered questions, such as how to connect to the chip to program it.
I was about to give up, but then I went to The Shoppe at Wulfden's web site just to check it out. This site offers a much better way to do this project by offering the chip set pre-programmed, or even better an actual kit containing all of the electronics ready for assembly. According to their instructions I would need to supply some breadboard, batteries and a flashlight to take apart.
I ordered the kit ($18.00 including shipping), and I'll post again when my son and have had the time to put it together.
This circuit could have been implemented more cheaply and efficiently using low voltage a 555 such as the TLC555 as the charge pump which can work all the way down to 1 volt.
It's 25 to 50 cents vs $12 using the 555 since you may have the rest of the parts in your junk box.
I wouldn't waste a micro controller for this app unless you want to add features like dimming or controlling an RGB LED array in place of the white LEDs so one can dial a color.
I was surprised no instructions were offered to make a replaceable lens protector from a recycling clear plastic from a 2 liter bottle or the inclusion of a static beam reflector for the lens assembly.
That didn't say anything about making it, just that you did make it. It's a bit complicated to do it right, you should use a current-regulated driver with the SSC P7, and it requires about 1.5A. Plain alkaline batteries aren't able to handle that kind of current. Also, saying that it will throw a beam 3 miles is exaggerated. The reflector is designed for a single small-die LED, unless you change the reflector it will make the beam very floody. I'd like to suggest that if anyone is interested in modding flashlights, check out www.candlepowerforum s.com. I've been a member there for several years (electromage), and it's one of the best resources around for flashlight information.
http://www.learnbaccarat.net
LED, unless you change the reflector it will make the beam very floody. I'd like to suggest that if anyone is interested in modding flashlights, check out www.xfreepornmovies.com s.com. I've been a member there for several years (electromage), and it's one of the best resources around for flashlight information.
I have A question what do you use for power normal alkine aa or ni-cd aa for the driver in luxonstar website @ BoRoPa