modifying a flashlight for projector

Thread Starter

softturns

Joined Jan 4, 2012
7
Hello,
I am an artist with little electronic knowledge, but have been researching making a slide projector with a Led light (the unit will be inside a manually rotating wooden display case). I originally bought a really bright flashlight (a cree MC-e 750 lumens flashlight powered by 3x 3v cr123a batteries) thinking that I could go cordless - but afterwards realized that the power draw would suck the life out of the batteries in only a couple of hours, and I need this to work for 6 hours a day for about 4 weeks (and having the gallery staff change batteries every couple of hours is not a very good solution).
Any suggestions? Here is what I'm thinking so far:

OPTION 1: I have thought about somehow attaching a motion sensor so that the light would only turn on if someone is in the gallery - but haven't had much luck figuring out how I would do this.
OPTION2: Alternatively, I have found a rotating plug (from 360 electrical) that I could probably use to solve the rotating power supply issue (instead of batteries) - but in this case I need to learn how to connect the LED star to an appropriate 3v power supply (mA1000?) - and a driver perhaps?
From what I have been reading, I need to be careful here, and though I have found some answers, it would be great to have some confirmation/advice.
Or perhaps there is another solution out there?
I really appreciate your help!
Sarah Jane <snip>
 
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R!f@@

Joined Apr 2, 2009
9,682
Hello Sarah,

What you are thinking is absolutely do-able.
Yes, you can put a LED into a projector which consumes much less power than any other light.

One thing you cannot do is run the light from a battery forever. It needs to be recharged. But you can go mobile if we can calculate your working hours as such.

This is something of trial and error method kinda thing. You should be willing to spend some money on it to test somethings to see if it suits ur needs.

Mind you that you are the one doing everything, we can only guide you. And to do this u need to take pictures of what you do and what you have.
 

Georacer

Joined Nov 25, 2009
5,181
Hello and welcome the the AAC forums.

I can't quite imagine how your rig will look like. What is your need for luminosity for this project. Since you started with a big flashlight, I imagine a few LEDs won't be enough for you. Can you post any pictures or anything to compare with?

I could suggest a car battery or smaller liquid battery to provide autonomy, but I don't know if it will suit the art project.

A sneaky cord extender with a wall outlet giving 9V to your torchlight could be another solution.
 

wayneh

Joined Sep 9, 2010
16,128
Yes, it's hard to visualize this without pictures or diagrams.

When you say "projector", I think of an image projected to a surface. To accomplish that you'll need quite a bit of light - you can calculate watts per square inch or such - and reflectors and optics to direct and focus the image. You didn't mention any of that, so I'm wondering what you mean by "projector".

Oh, and I don't know if it would help, but you might want to use inductive charging, where a battery can be charged without direct contact to the charger. It's used in electric toothbrushes, for example.
 

Thread Starter

softturns

Joined Jan 4, 2012
7
Thanks for your replies!
Here are some pictures of what I have so far.
The option that I am currently exploring involves the following:

After visiting a “LED center” website I think I have a better idea of what I need to do. As I mentioned I am using a cree MC-e, which according to the “Cree website” uses 700 mA and 3.5 Volts maximum and puts out 750 lumens maximum. As I understand it to connect this LED bulb to a power outlet I need to get: [1] an AC adapter (5 volts, 1000mA), [2] a resistor, [3] a rectifier (to turn the AC into DC). I hope that when I put (solder) this together it will work properly, with a high output of lumens (the original flashlight advertises a 750 lumens output to begin with) and that it won’t burn out my LED or start a fire. Maybe you can confirm whether this idea will work or not?


If there is a battery alternative that would be simpler - this would be better of course, but it needs to last about 6 hours a day for 20 days (recharging overnight).
Thanks again for your help, I appreciate it!
 

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wayneh

Joined Sep 9, 2010
16,128
Worth a thousand words, thanks for posting those pics.

For power, I'd look for a power supply that is already regulated DC. That'll save you some effort. A cellphone charger is typically 5V, 1000mA DC, for instance. But something you could use directly (maybe a battery charger for the appropriate battery?) would be nice.
 

Georacer

Joined Nov 25, 2009
5,181
I think that a wall wart can replace your batteries and let you run your torch full time.

Can you post a link to a site describing your torchlight? We need to see its specifications in voltage and current in order to choose a wall wart.
 

strantor

Joined Oct 3, 2010
5,178
this is fairly straightforward and you had (1/2 of) the simplest solution in the first post. Install the rotating plug in your box. Get a 9v "wall wart" like this one and plug it in. cut the plug off the wall wart (before plugging it in), strip the wires back, and solder the + wire to the little nipple at the end of the battery tube, and solder the - wire to the case of the flashlight.
 

Thread Starter

softturns

Joined Jan 4, 2012
7
Again, I really appreciate the feedback from you guys, it has been lightning fast! Here is a .pdf file with specifications about the LED light that I think is inside the flashlight:
http://www.cree.com/products/pdf/XLampMC-E.pdf

I think the LED is MC-E white.

As I mentioned the light runs from 3 lithium 3volt batteries, the guy in the store where I bought it was advising me to use a 3 volt adapter because the flashlight is wired with a parallel circuit. I don't know if this helps .... maybe not.
 

Markd77

Joined Sep 7, 2009
2,806
When you put the batteries in the torch, do the ends of the batteries touch each other?
If so you've got series batteries and need a 9V supply.
 

strantor

Joined Oct 3, 2010
5,178
When you put the batteries in the torch, do the ends of the batteries touch each other?
If so you've got series batteries and need a 9V supply.
yeah I would be very surprised to learn that the guy is correct. I have never seen a flashlight with the batteries in single file, and in parallel. there would need to be dividers between the batteries. if it's a hollow tube with no dividers, then they are in series and it's 9V.
 

Georacer

Joined Nov 25, 2009
5,181
The pdf is referring to the LED die, instead of the torch itself. It gives at about 2.5V to 3V per die, and you probably have 4 dies in the torch lamp.

Do they operate all at the same time? Are there different modes?

Some more pictures of the battery holder or even better a torch spec sheet would help.
 

R!f@@

Joined Apr 2, 2009
9,682
You guys are going way too fast for a beginner.

Here first try this.
Before doing anything just show me the battery Used in the torch. I may have the same type myself.
Tell us if the torch came with a charger..

Next do this and tell us the result. Take your phone, put it in camera mode.
If you don't have a phone cam, then find a friend who does. switch on the cam in the phone. Next shine the torch at the camera lens.

And notice the picture u see from the cam, no need to take any picture, just observe.
Tell us if it is a clean steady picture or do you see horizontal black lines rushing up or down with in the image.

Post back, this is important.
 

DerStrom8

Joined Feb 20, 2011
2,390
As I mentioned the light runs from 3 lithium 3volt batteries, the guy in the store where I bought it was advising me to use a 3 volt adapter because the flashlight is wired with a parallel circuit. I don't know if this helps .... maybe not.
Most guys who sell flashlights in stores don't have the slightest clue what they're talking about. I've even had problems with the employees at Radioshack, but then again, that's no big surprise :rolleyes:
I wouldn't be at all surprised if he didn't even know the difference between a parallel circuit and a series circuit. That is definitely the kind of thing you'll want to check yourself.

One of the main things with this is focus of the light. You'll need lenses to focus the beams perfectly in order to get a clear image. Looking at your setup, I would assume you know this already, but I just wanted to be sure.

As for powering it, I second (third?) the motion to use a low-profile corded wall wart. It can easily be hidden away, and will provide you with constant, reliable power for your flashlight.

I wish you the best of luck on this project. It looks like you have a great start so far! :)

Regards,
Der Strom
 

Thread Starter

softturns

Joined Jan 4, 2012
7
Hello again,
Yes, so it looks like I have the batteries in series (they line up behind one another and connect). The Led component connects to the positive end of the battery chain via a curly wire at one end, and at the back end (negative side of the last battery) there is a nipple-like part that I guess connects to the on/off switch at the rear of the flashlight.
The video I tried to upload didn't take, so here's a link:
http://www.softturns.com/flashlight.html

In the video I show the parts of the flashlight and batteries, and show that the beam is a solid white light when directed into the video camera lens.

The wall wort idea makes sense to me, and I will buy one tomorrow, just a bit unsure still about the actual soldering part (someone who has experience will help me do this - but which wire goes where?)
 

Georacer

Joined Nov 25, 2009
5,181
Yeah, AAC's vBulletin doesn't support video uploads.

Yep, definitely in series. Get a 9V adapter and you 're good to go.

If I see it correctly, the + terminal goes towards the inside of the torch, towards the light itself. usually the - terminal is on the light case, that silver case of the LEDs.

If you solder the + and - terminals of the adapter there, the torch will light. BUT! if the surfaces to be soldered lie onto a plastic case for integrity and support, the soldering iron will melt them. More than once, I had to use tape to attach contacts, instead of using solder.
 

R!f@@

Joined Apr 2, 2009
9,682
Hmm

Standard torch. No PWM.

3 Series cells. Quite Simple.

I like to know what is written on the cell. The Cell voltage.
 

DerStrom8

Joined Feb 20, 2011
2,390
From the video, it looks like the top end of the flashlight is the positive end, and the back is negative (just like a standard one). I would assume the case is grounded (connected to negative) just looking at the video, so I think if you connect the + side of the wall wart to the "spring" directly underneath the LED, and the - side to the case, it might work. If the case isn't grounded, you'll have to find the return path, but I'm pretty sure the case is negative.
 

strantor

Joined Oct 3, 2010
5,178
yup yup. That's what I'm thinking. since I saw the video, it should be easy to do. unscrew your white part out, run your + wire through the tube & solder (or even just wrap it real tight) it around the spring. Then put the light abll back together and stick the - wire in the end of the tube and screw the cap down on it.
 
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