Homemade LED Light

[**DONOTDELETE**]

I just got an itch to get obcessed with LED flashlights, so here I am... After seeing the lightwave 2000 in a catalogue I just had to investigate the subject. After researching the matter I just ordered a lightwave 2000 and a Photon II to play with. Unfortunately I could not wait for them to arrive :/ so I drove down to Radio Shack to see what I could waste my money on.

I bought 1 Blue LED and 2 White ones, and a 47ohm resistor to play with. After getting home I broke out the soldering iron and a old paper towel roll (my makeshift battery compartment) and went to town. After scavaging components from an old handheld game I had, I now have a working (ugly) led light. It has an extremely wide beam that does not go very far, but works well up close. I am planning on refining it into something that actually resembles a flashlight. My question is, what LED has a far thin beam that goes dirrectly forward? My plan is to make a 4 battery, 5 LED model with 4 wide beam LED's and 1 thin peircing beam in the center. Any tips would be appreciated.

 

[DaveH]

Good job!

Beam spread depends significantly on the type of LED you buy. Some LED's will have a viewing angle or dispersion angle, the narrower the measure the tighter the beam.

Some LED's are specifically ground so that they throw a particular beam.

Many LED's as you've discovered have a wide dispersion angle. You can try using a small convex (?) lens to try and focuss the beam.

The easiest thing to do is buy the same LED's that are used in the Photon II's, I believe photon does sell them. These have a pretty tight beam.

DaveH

 

[**DONOTDELETE**]

Hmm... I just turned the ugly LED Turd into a flashlight looking thing...

Except I got greedy and I lowered the resistor to a 33ohm one instead of 47ohm. Now it is much brighter but I would guess it is going to go *poof* soon?

It is two LED's running on 4 AA batteries... 6 volts with a 33ohm resistor is too much juice right?

 

[**DONOTDELETE**]

Hmm... It appears that I am overpowering my LED light to a great extent.

Oh well... you live you learn...

Now I think I am going to switch to a 9volt power supply. Is there a reason why 9volt batteries are not used very often? It seems to me that I can make a 9volt LED light many times smaller than that with many AA or similar batteries. Also, I hear that hooking them up in series is better than in parrallel. Something about a more even current distribution?

 

[**DONOTDELETE**]

There are trade offs for using 9v battery rather than 3 or 4 AA's.

My 4 LED headlamp that I built (which works really well) uses a 9 volt battery. There are two separate banks of two diodes in series. The gain here is that with a 9v and 2 diodes in series, you draw half the current compared to running two in parallel with 4.5V AA's. But then of course, the 9V battery has less capacity than AA cells so the tradeoff is more in size. But my headlamp gets a good 24 hours of constant light befor the brightness drops to half.