I am looking to build an IR light source to use with my Sony video camera. I purchased a cheap IR flashlight that has 25 IR led lights on it, but I want some thing that would put out a wider beam of light.

I purchased 50 of these -Infrared LED 1.1-1.6V 20mA 850nM- and wish to build a light source out of this. This is going to be my first build of any thing like this and I don't really no where to start.

If any one could point me in the right direction, I would greatly appreciate it.

Thanks in advance.

 

I would check voltage drop @ 20mA of all led's and put them in piles of = V drop. Just for discution assume a matrix 7X7. Select values[ on paper first ] to give about a 9.45 V for 7 led's,assuming a 12V supply,adjust 9.45V up or down to give greatest number of strings of = V. Figure value of current limiting resistor: 12V- 9.45 = 2.55V/ .02 = 127 or std value of 130Ω. Leftover strings might have 6 to 8 led's,just figure them seperatly.

To give desired beam spread, use a segment a plastic bowl [ approx. hemispherical ]. For narrowest beam , use 7 mm centers , for wider beam spread centers as desired. Make a paper patern .marking centers then led lead holes. Dampen paper and form over bowl, tape in place when dry. Remember holes for resistors, 1/4 W. Drill lead holes as snug as possible. Insert leds, bend leads to over lap and solder

 

I goofed on thumbnail.

 

Thanks, this definitely helps. I still have not received the LED's but now I know where to start. Thanks again.

 

How far away is the object? If it's more than about 15 feet away you might want to consider switching to a larger LED, like a 1 watt, and an orange peel reflector. There are companies that sell an LED mounted to a star/heatsink, and it comes with a reflector. It's a P60 type, and will swap right into many lights, such as a Surefire 6P. You could always build an array of them if you need a lot of lumens. www.dealextreme.com has the P60 drop-ins as well as the individual LED's.

What were you planning on using for a battery pack and driver?

Here is a star:

http://www.dealextreme.com/details.dx/sku.13961

 

Bernard,

excuse me for asking this question, but like I said I am new to this so I just need a little clarification.

On the diagram you posted, you are showing the (+) side of the power supply going into the resistor. then the led's connected with the (-) being at the end. This would mean that the power would flow through the (-) side first, then through the lights, then into the resistor. The whole conventional vs. electron flow notation has me a little confused. I thought since the power actually flows from (-) to (+) that the resistor should be connected on the negative side first before leading up to the lights. So that way the power is then regulated to the voltage I need to power the 7 led's.

Or is your diagram actually using conventional flow notation and when I do connect every thing I actually do it according to the electron flow notation and connect the resistor to the (-) side of the power supply first, before leading up to the led's?

 

The order of placement of the parts makes no difference, just be sure cathodes of LED's go to the most - side of circuit.

 

Okay, thank you

 

Check this out, it applies...

http://forum.allaboutcircuits.com/showthread.php?p=112953#post112953

 

I just want to say thanks for the help. I put together a set of led's that was 7x7. I now have a nice IR light for my camera with 49 led's that works well. This is a very informative site with some good people to get advice from. Now I just gotta decide what I want to make next.

 

It's refreshing when a Threaded gives a final report, come back again sometime.