HELP! DIY moonlights not working!

[dralarms]

My thinking is he wanted to keep the pos and neg as far away from each other as possible. Or he could have a thing for yellow

 

[bckane]

I used something like pvc pipe, but its nylon fencing post.
here's some photo's of the finished project
http://bellsouthpwp.net/b/c/bckane/moonlights/

 

[djxtreme504]

I recently put together a set of moonlights using a 9v dc power supply and 3 LEDs from lsdiodes.com. Also, I used the calculator from http://metku.net/index.html?sect=view&n=1&path=mods/ledcalc/index_eng this site which said I should use one single 91 ohm resistor. The lights all look great and each has 3.3v across. However, the resistor gets very hot after just a few seconds. Is this normal? Will it cause problems if it is plugged in for any length of time? Here is a wiring diagram. If I were to use 3 separate resistors, what size should they be if I wanted 3.5v across at 20 ma?

 

[dralarms]

Your probelm is the resistor, it's probally a 1/4 watt or 1/2 watt, you need a 1 watt or higher to do it like that. If you go to 3 resistors then the 1/4 watt or 1/2 watt will be fine. HTH

 

[djxtreme504]

Yes, the resistors are 1/4 watt. What ohm would I use if I used 3 resistors? Whatever ohm the calculator tells me for a single LED?

 

[dralarms]

9vdc drop down to 3.5 vdc 9- 3.5 = 5.5 5.5 divided by the current draw of your led will give you the resistor needed. If it 20 ma the 5.5 divided by .02 is 275 ohm. If the current rating of the led is 30 ma then a 183 ohm resistor will work.

 

[JProx]

gerald that's not fair! how do you get all the easy questions!?

 

[dralarms]

how do you get all the easy questions!?

you call that easy? lol I had to dig the book out to figure that out.

 

[JProx]

you suck i know all that garbage off the top of my head..

 

[dralarms]

you suck i know all that garbage off the top of my head..

I'm just not that smart. To much time in the Air Force when I was younger.

 

[JProx]

lol it's not really fair to you.. this is all quarter 1 stuff for me, the stuff you MUST master in order to understand what the hell is going on in the wide world of Transisotrs (q4),digital (q5) and Radio,fiber,cooper transmission systems (quarter eight)

so anyway sorry for beating up on you, but those questions are easiest since it's just 2 little calcs, and the theory is very straight forward...

sorry gerald,

bry

 

[dralarms]

this is all quarter 1 stuff for me, the stuff you MUST master in order to understand what the hell is going on in the wide world of Transisotrs (q4),digital (q5) and Radio,fiber,cooper transmission systems (quarter eight

Do I ever feel dumb.

so anyway sorry for beating up on you

No problem. I'm jus tyour little ole punching bag.

but those questions are easiest since it's just 2 little calcs, and the theory is very straight forward...

I agree. With what I do for a living it's simple resistance calculations and deciding which terminal to use next.

I own an alarm company, install, service, and also do board level repairs. Nothing fancy.

 

[JBFett]

I don't think I was clear enough on my black/yellow wire problem. Flat telephone wires have a smooth edge and and edge with a crease down the middle. What I did was attach the rj11 with the crease side down. Depending on which random end of the telephone wire I grabbed when I attached the connector, sometimes the yellow was on the left and sometimes the right. I didn't figure it made a difference because all telephone wires have one end which has yellow on the left side and the other end has yellow on the right side. I always soldered the resistor to the shorter pin on the LED its just sometime I then had to solder the resistor to the yellow wire and sometimes to the black. The mix of yellow on the left to yellow on the right is somehow perfectly even, nine to nine. None of my lights appears to be brighter than the others, but it is hard to tell inside the canopy. My lights have been running (either with no Pot or the Pot turned down for maximum brightness) 24/7 for a week Monday the 10th. Do you think some of my lights are going to burn out? If so, when I remake then should the yellow wire be on the left or the right.
Thanks

 

[bckane]

I dont remember short or long pin.....But what I did was the flat side of the led is the negitive side, which I connected all together, the other side is the postive, whcih I connected a resistor to each leg

My Moonlight setup:http://bellsouthpwp.net/b/c/bckane/moonlights/

 

[dralarms]

JBfett,

Your lights should be fine, By using both ends of the rj cord you just reversed the polarity. No problem.

 

[JBFett]

Whew!! I ran to radio shack today and picked up a 100k Potentiometer. Better than than the 1M but I may try the 50k just for giggles.

 

[JProx]

well i am glad i could help. 1meg is pretty darn huge for a 5v circuit and usually with the larger Pots, when you crank them down it doesn't equal 0 resistance like it should. so even when it should be 0 it's probably a thousand or so ohms of resistance. which in some circuits is fine, but when you have a circuit using 10-100ohm resistors it can really throw everything off as you might have already seen.

i have tried both the 50k and the 100k before, and i liked the 50k, don't remember if there was any reason, i am pretty sure i just had more of those on hand at the time.

 

[KFEdaddy2k]

Resurrected again....

Just a quick note that I may have found a great cheap power supply for DIY moonlights. If you have any extra Nokia cell phone chargers laying around the house, check them out. Mine are 3.7v 350mA. You'd probably still want a small resistor in the circuit on each leg just to even things out a bit, but it might save you the $5 -$8 for the power supply at your local radioshack.

Kurt