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Old 04-18-2004, 09:09 PM   #51
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well.. i should have clarified in that last post.. my mistake.

a pot is a completely safe addition to the circuit. the only reason i went on a tangent about how they are not a true dimmer, is just so i wouldn't be corrected by somebody else, later down the road and plus i believe in supplying more information on a electronic subject than necessary just to make sure there isn't any confusion later.

a pot would be 100% safe if you build the circuit in parallel with a resistor tied to each led. the way the system works.. is that electrons flow from the source to the resistor which steps down the voltage, and any incoming current to an acceptable levels for the led. then the electrons flow into the led, turn it on.. then return to their source. here's a wiring diagram http://12598.tripod.com/dia3.JPG. the resistors on the led's are just doing a coarse voltage/current adjustment. when you install the pot, put it on between the led/resistors and the source shown in the diagram. the pot will actually do a fine voltage/current adjustment, just dropping enough voltage to get the led's to turn on, but not to their max output.

the semi complete list of how to destroy an led [some personally tested!]
exceed their voltage and/or current ratings,
install them in a circuit backwards (opposite polarity) without a limiting resistor
making direct contact with a soldering iron for more than 15seks (which i have done, and they still worked.)
physically damaging them, by cutting, crushing, ect
dunking in water when power is applied (shorting them out)

if you under power them, then they won't turn on (untill more voltage is applied) or they will barely turn on (creating the illusion of a dimmer switch) under powering a electronical device will almost never destroy them, so their is no harm in under powering them, led's only die when you apply too much

one thing you might want to take a look at, is getting a medium to fit between the led's and water to diffuse the light. the diffusing plate will actually spread the light through out the entire tank, and avoiding the spotlight effect. you could always use the pot and diffusing plate to really fine tune their output if you wanted. but i would recommend trying the plate idea first alot of people on the forums like that better than the pot, probably because it avoids the spot light effect from the led. HD sells sheets of plastic that are made to diffuse light produced by a florescent light system, you see those in use alot in commerical buildings and schools. just cut it up to fit, and then install the pot for maximum adjustments. those panes, in my local hd, are right next to plastic eggcrates, that are used for the same purpose too.
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Old 05-02-2004, 09:26 AM   #52
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I set up some moonlights using thelebos modular design and when I add the Pot (I inserted it on it's own phone line between the power supply and the first line expander) the light output is drastically reduced. I'd guess that the maximum output is 60-80% of non-Pot output. I bought all the parts thelebos.com sells and the only thing I changed was the telephone wire. Wal-mart apparantly only sells six wire phone lines. I tested the lights with the black and yellow wires they worked fine. However, sometimes I had to connect the resistor to the yellow and sometimes to the black. All the lights continued to work fine so I just used what worked. Did I screw up? Does anyone know what's wrong?
Thanks in advance for any replies I might get!
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Old 05-05-2004, 02:45 AM   #53
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just when you think this thread is bout to freakin' die.. it's ressurected...lol

JB i am the local electronics guy here on the forum, i would love to help, but thelebos is a paysite, i can't get access to the diagram to make heads or tails what role the telephone wire plays, so in short i can't help unless i get some insight on what sort of circuit you have.

second (and maybe becuase it's 2am in the morning) i can't tell what the problem you have is, a pot = potentiometer = usually a large resistor that has the ability to be variable (twist the input one way it goes higher, turn it the other it drops) the electronical theory is.. you have voltage, resistance and current. resistance and voltage generate current, and a portion of the voltage is consumed over the resistance. so if you're saying the led's aren't getting very brite with the pot; it's doing exactly what it's suppose too. the pot is dropping voltage, off the incoming source, and taking it away from the leds, less voltage = less light from the diode. i could go on another tangent explaining everything.. but i am sure if you re-read this thread you will find all the technical info.

Maybe if you sent me [via ijedi@hotmail.com] the wiring diagram, or anything thelebos sent you, i can help.. but as it stands right now, i know nothing about thelebos.
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Old 05-05-2004, 08:15 AM   #54
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jprox, pm me with a different email addy and I'll send it to you. the file is large and hotmail won't accept it.
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Old 05-07-2004, 06:22 AM   #55
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I got a little impatient and picked up a similar Potentiometer from radio shack. At maximum it doesn't dim the lights (compared to when it's removed) but you can only turn the knob about a 1/8" before the lights completly dim out. Not enough control.
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Old 05-07-2004, 07:06 PM   #56
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there are ways to maximize the dimming effect of the pot, by installing a resistor in parallel with the pot. however since i have no idea what circuit you have, specifics ect, i can not suggest a resistor size, too large of a resistor and the led's get very little voltage, to small and the current can blow the leds. i have talked to 2cents.. about getting the schematic but haven't recieved anything yet.. so just hold tight and hopefully we can get this figured out for you.
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Old 05-07-2004, 07:40 PM   #57
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Jprox,

I sent it to you. i'll try again. Send me your email addy again.
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Old 05-08-2004, 03:55 AM   #58
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Thank you Gerald for the extended help.

jb, i have read over the thelebos
your first problem was that when the pot was turned off, the led's brightness was still pretty low. here's the theory of whats wrong,

idea 1: with anything manufactored nothing is 100% perfect, as an example the 4th color band on a resistor (gold,siler, ect) is the tolerance band which states how close it is to the face value. you might have gotten a bad pot, where turned all the way down there is still enough resistance to 'steal' voltage from the leds. or you might have broken the pot, some variable resistors can only be wound a 1/2 turn in either direction, and any more will break them internally, not sure if it applies to you, but something to keep in mind.

idea 2: i personally feel a 2.5 mega-ohm variable resistor is way to large. i have suggested more than a few times in this thread 50k is large enough. the dimming effect might not be as subtle, but it gives pretty good results, if you don't like the results step it up 100k. and then there is always 'tweaking' the pot for additional results (adding a standard resistor in series with the pot to increase resistance, or parallel to decrease)

next you had a problem with black/yellow wires. from what i have read and seen, it sounds like there might be a loose connection somewhere, or at some point you switched the colors around. crimping rj11 and rj45 are tricky and difficult for beginners, i installed ethernet cable in my last house, and it took alot of wasted plugs till i got a working cable, the first cable i tried to crimp i wasted like 18plugs. try visually checking to make sure the cable is in contact with the cooper jumpers in the rj11 plug. and check to see if the black/yellow wires are where they should be.

the electronical theory behind all this.. is that electrons flow from a negitive/netural side of a power source, and through the circuit till they reach the positive side of the source. some electronical devices have a polarity, Diodes are the most common though. the cathode is the negitive side, and that side needs to be on the negitive rail of the source. since electrons flow up through the negitive side, the resistor needs to be added there, before the led to trim off the voltage and do any current adjustments. the resistor here can also be called a 'current limiting resistor' where it will actually protect the led from any voltage/current danger.
note: hooking up leds backwards can destroy them, if there is no current limiting resistor in place.

now if you switch the power lines (yellow/black wires) the led won't lite, since the led is polarity specific. the cathode end needs to be on a negitive rail, if they aren't then the led won't lite, which is why i believe you might have the wires switched somewhere. so double check you're wiring, and trying swapping the pot with a smaller one, and let me know the results and we can work from there.

Personal opinion: one thing i don't understand though.. is why did the mastermind at theleos.com not use red/black instead of yellow/black/white. i mean red/black are colors that most people identify as positive/negitive, look at your car battery.. red/black terminals. i mean even black =negitive and yellow = positive would have better... i found it so annoying i would comment on it.
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Old 05-08-2004, 07:04 AM   #59
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Quote:
is why did the mastermind at theleos.com not use red/black instead of yellow/black/white. i mean red/black are colors that most people identify as positive/negitive, look at your car battery.. red/black terminals. i mean even black =negitive and yellow = positive would have better... i found it so annoying i would comment on it.
He did this because the yellow black combo are on the outside edges of the flat cable.
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Old 05-08-2004, 04:25 PM   #60
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sorry gerald, it was late last night.. and probably from mental fatigue i was getting annoyed. however besides the fact they are on the outside, what is the explanation for the black = positive, and yellow = negitive situation though ? i mean if you didn't want to go red/black.. at least keep something common [ie black = negitive]. lastly you can easily use the wires in the middle if you wanted, it doesn't add much (if any) difficulty in final assembly. just my 2cents on this one.
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