Any update on this? anxious to see how its going.
DIY LED driver for reef lighting
- Thread starter der_wille_zur_macht
- Start date
Any update on this? anxious to see how its going.
terahz
1x10^12 Hz
Guess what showed up today.
I will try (but don't promise) to populate one of these on the weekend and see how it works. If it doesn't happen this weekend I should be able to work on it early next week, so soon I'll have something to report.
How I wish I was in summer break...
EDIT: does anyone know how to make a pad continous with a plane in eagle? I tried to make these pads basically exposed plains, but it insisted on making a clearance around them and connect them with 3 tiny short traces. Kind of defeats the purpouse.
I will try (but don't promise) to populate one of these on the weekend and see how it works. If it doesn't happen this weekend I should be able to work on it early next week, so soon I'll have something to report.
How I wish I was in summer break...
EDIT: does anyone know how to make a pad continous with a plane in eagle? I tried to make these pads basically exposed plains, but it insisted on making a clearance around them and connect them with 3 tiny short traces. Kind of defeats the purpouse.
Dumb question ... this doesn't seem cheap, is it to give more PWM inputs for more 'granular' control of the LEDs'? Or am I mis-calculating the costs? I'm still looking at all options so I may have missed something, and yes, I've read most of this thread but it's all swimming in my head :spin3::fun5:
My goal is to have 3-5 banks of LED's over my 120 (4x2x2), but each bank I would probably want to have the RB's and CW's (maybe a couple of NW or WW) independantly controllable, so I think that means I need at least 6 and maybe 10 separate power supplies with PWM inputs.
I don't have a controller, but would build an arduino based controller or break down and buy an Apex. What popular controllers (Apex, reefkeeper, etc) can do more than 6 PWM outputs?
I think the concensus is it doesn't make that much difference but I wanted to 'progress' the lighting intensity and direction across the tank to simulate the sun moving. So I think I may end up having to build controllers just so I can have a LOT of input/banks at a reasonable (?) price.
Sorry for rambling,
== John ==
TheFishMan65
New member
terahz, flip the coin over what is the territory that you got??? ooooh from Philly. Not bad a few imperfection I don't think it is mint
I am not real familiar with Eagle, but I think that is some kind of thermal relief. Look for setting related to that.
I am not real familiar with Eagle, but I think that is some kind of thermal relief. Look for setting related to that.
TheFishMan65
New member
John,
I think those prices seem high. I did an 8 driver board and it is about $35 to populate. A lot depends on the price of the parts. I have seen Cats from $1.92 (Future Electronics) to $5.00 (I believe).
The only way i know it to progress lots of bank and color is with multiple controllers.
I think those prices seem high. I did an 8 driver board and it is about $35 to populate. A lot depends on the price of the parts. I have seen Cats from $1.92 (Future Electronics) to $5.00 (I believe).
The only way i know it to progress lots of bank and color is with multiple controllers.
Last edited:
kcress
New member
As Fish sez. I think you examine the footprint of the device and click some button that is "no thermal relief".
Looking good, love the compact design and LED count. Send me one and I will assemble it for you..
terahz
1x10^12 Hz
TheFishMan65, kcress, thanks for the thermal relief pointer. I'll take a look later today.
Boostable, I still don't know if the boards work at all Let me test this first batch. As for the max number of LEDs it is 72V/Vfw of your leds. Nothing in the design of the board prevents you from putting components for 72V, or at least that's what I think . I believe the controling factor for number of LEDs will be how easy/cheap is to find a suitable power supply.
Boostable, I still don't know if the boards work at all
Let me test this first batch. As for the max number of LEDs it is 72V/Vfw of your leds. Nothing in the design of the board prevents you from putting components for 72V, or at least that's what I think . I believe the controling factor for number of LEDs will be how easy/cheap is to find a suitable power supply.Ok, so i'm locking for away to dim my LED drivers
My drivers are build out ot CAT 4101 chips, and need a 5V PWM signal to dim.
problem is, everything I find is all 0 to 10V, not 0 to 5V
is there anyone that has CAT 4101 driver chips thy dim, and if so how do thy do it.
- Rapid LED had there own version to dim light, but again 0 to 10V, I mailed them, and thy say I might be able not to supply it with 10V but with 5V, but thy cant guarantee it, so for now I'm not ordering it, because I want to be 100$ shore it is going to work.
- some also suggest to have it dimed by a ARDUINO based unit, problem it the ARDUINO is a bit out of my knowledge,
any help ore suggestions ??
for your info:
the drivers are 3 boards, each holding 2 sets of 4 chips, 2 boards (4 sets, 16 chips in total) will be my white, and 1 board (2 sets, 8 chips) will be my blue
My drivers are build out ot CAT 4101 chips, and need a 5V PWM signal to dim.
problem is, everything I find is all 0 to 10V, not 0 to 5V
is there anyone that has CAT 4101 driver chips thy dim, and if so how do thy do it.
- Rapid LED had there own version to dim light, but again 0 to 10V, I mailed them, and thy say I might be able not to supply it with 10V but with 5V, but thy cant guarantee it, so for now I'm not ordering it, because I want to be 100$ shore it is going to work.
- some also suggest to have it dimed by a ARDUINO based unit, problem it the ARDUINO is a bit out of my knowledge,
any help ore suggestions ??
for your info:
the drivers are 3 boards, each holding 2 sets of 4 chips, 2 boards (4 sets, 16 chips in total) will be my white, and 1 board (2 sets, 8 chips) will be my blue
TheFishMan65
New member
Kevin you can use the one from RapidLED. If you drive two resistors of the same size.
Plus out - resistor - resistor - minus out
Then between minus out and the mid point of the resistors will be half the voltage of plus out. This is because voltage = resistance * current. Both resisor are the same and have te same current so both drop the same voltage. Now the problem the CATs pull a little current so one resistor will drop a ltille more voltge than the other. Aslo too small a resistance and you over drive the power supply for the network. The good news is that the extra current causes more voltage in the first so in reality you may never reach 5 volts, but IIRC the threshold is around .5 volts.
I would think 25 (2-5 watt)ohm resistor 10 volts / 50 ohms = 200 ma would be ok. A few extra miiliamps wont change it much.
Hopefully someone will correct me if Ihave this wrong.
Plus out - resistor - resistor - minus out
Then between minus out and the mid point of the resistors will be half the voltage of plus out. This is because voltage = resistance * current. Both resisor are the same and have te same current so both drop the same voltage. Now the problem the CATs pull a little current so one resistor will drop a ltille more voltge than the other. Aslo too small a resistance and you over drive the power supply for the network. The good news is that the extra current causes more voltage in the first so in reality you may never reach 5 volts, but IIRC the threshold is around .5 volts.
I would think 25 (2-5 watt)ohm resistor 10 volts / 50 ohms = 200 ma would be ok. A few extra miiliamps wont change it much.
Hopefully someone will correct me if Ihave this wrong.
Gorgok
New member
Sorry for just reading the end here, but i got a quick question that my mind can't pick the answer to. (Its been a long time since i did any electronics stuff, i may sound stupid.)
If i wanted to make a LED driver, using the Cat4101 chip, i need to feed it 5V, like from a Mean Well LPV-60-5. But driving LEDs totaling the chips max 25V (about 6 LEDs, right?) at 1A makes it 25W right? And wouldn't that mean the input is drawing 5A? (5V in, 25V out, 1A, to 5A?) Making me need 1 power supply for each chip (and then a useless idea, so this can't be right, otherwise people wouldn't do it)... Or is it the resistance that matters, and then the V=IR stuff and 25/1 changes to 5/.2? So i could run 16 chips off that one supply? Or is the current draw always 1A and then i could still run 8 strings of roughly 6 LEDs at 1A off that 1 supply and 8 chips (48 LEDs, at roughly the same price as a Mean Well ELN-60-48).
I am sure there is a huge logical fallacy that i just can't get my head around because this is not something i have even thought about in a long time.
Would i need anything besides these chips, the resistors for the RSET to set current (read something about a specific type of adjustable resistor somewhere, i'll find it later), and the small bypass cap suggested in the data sheets?
If i wanted to make a LED driver, using the Cat4101 chip, i need to feed it 5V, like from a Mean Well LPV-60-5. But driving LEDs totaling the chips max 25V (about 6 LEDs, right?) at 1A makes it 25W right? And wouldn't that mean the input is drawing 5A? (5V in, 25V out, 1A, to 5A?) Making me need 1 power supply for each chip (and then a useless idea, so this can't be right, otherwise people wouldn't do it)... Or is it the resistance that matters, and then the V=IR stuff and 25/1 changes to 5/.2? So i could run 16 chips off that one supply? Or is the current draw always 1A and then i could still run 8 strings of roughly 6 LEDs at 1A off that 1 supply and 8 chips (48 LEDs, at roughly the same price as a Mean Well ELN-60-48).
I am sure there is a huge logical fallacy that i just can't get my head around because this is not something i have even thought about in a long time.
Would i need anything besides these chips, the resistors for the RSET to set current (read something about a specific type of adjustable resistor somewhere, i'll find it later), and the small bypass cap suggested in the data sheets?
liquidarts
New member
The PWM dimming signal of 0-5v from the Arduino is all you need along with a 24vPS Gorgok.
Plenty of schematics out there for a PWM using a 555 timer..
Gorgok
New member
After my brain fart of last night i have been looking for 24V power supplies through many different means having little luck getting anything that seems like it would work. My main goal of course with a cat4101 build is to reduce the cost from the $30 or so driver for 12 LEDs down to something reasonable.
I am probably doing this search thing all wrong, as i don't really find anything most of the time. Or then its that 24V, high amp, DC power supplies are simply either very expensive or not made. However, i did just hit one thing that looks like it could be a winner, except its a screw terminal metal case deal with ventilation holes and a fan. But $44 for 24V 14.6A DC PSU... Maybe i could hide it someplace safe.
Anyway, lets do some math. First the ELN-60-48 setup with a single string of 12.
$30*LS/12*LS = $2.50 per led (LS=1)
Total driver cost = $30
This is a fixed cost really, but for future comparison sake i'll add a set of 7 strings of 12 LEDs for 84 LEDs total.
$30*LS/12*LS = $2.50 per LED (LS=7)
Total driver cost = $210
Then a single string of 6 on a Cat4101 with the 14A PSU.
($44+LS*$3.36)/(6*LS) = $7.89 per LED (LS=1)
Total driver cost = $47.36
But the PSU can handle up to 14 strings at 1A, more at less, but you need another Cat4101 for each string too. 14 strings is 84 LEDs
($44+LS*$3.36)/(6*LS) = $1.08 per LED (LS=14)
Total driver cost = $91.04
The difference is pretty cool. At 3 strings of 6 you pay more per led with this PSU/Cat4101 combo, but after that you pay less. Even if you have to buy another PSU once you hit 15A on 15 strings you will still be roughly $1 less per LED than with the ELN setup. If for whatever reason you hit 20+ strings you can actually save money on the Cat4101 (on Mouser) by buying 25 at the reduced price.
Now i just wish the LEDs weren't so expensive and i could buy 84 of them for a reasonable amount...
I am probably doing this search thing all wrong, as i don't really find anything most of the time. Or then its that 24V, high amp, DC power supplies are simply either very expensive or not made. However, i did just hit one thing that looks like it could be a winner, except its a screw terminal metal case deal with ventilation holes and a fan. But $44 for 24V 14.6A DC PSU... Maybe i could hide it someplace safe.
Anyway, lets do some math. First the ELN-60-48 setup with a single string of 12.
$30*LS/12*LS = $2.50 per led (LS=1)
Total driver cost = $30
This is a fixed cost really, but for future comparison sake i'll add a set of 7 strings of 12 LEDs for 84 LEDs total.
$30*LS/12*LS = $2.50 per LED (LS=7)
Total driver cost = $210
Then a single string of 6 on a Cat4101 with the 14A PSU.
($44+LS*$3.36)/(6*LS) = $7.89 per LED (LS=1)
Total driver cost = $47.36
But the PSU can handle up to 14 strings at 1A, more at less, but you need another Cat4101 for each string too. 14 strings is 84 LEDs
($44+LS*$3.36)/(6*LS) = $1.08 per LED (LS=14)
Total driver cost = $91.04
The difference is pretty cool. At 3 strings of 6 you pay more per led with this PSU/Cat4101 combo, but after that you pay less. Even if you have to buy another PSU once you hit 15A on 15 strings you will still be roughly $1 less per LED than with the ELN setup. If for whatever reason you hit 20+ strings you can actually save money on the Cat4101 (on Mouser) by buying 25 at the reduced price.
Now i just wish the LEDs weren't so expensive and i could buy 84 of them for a reasonable amount...
TheFishMan65
New member
Or save at Future Electronics where the CAT is $1.92.
Kevin, a 555 circuit would work also
This is not strictly true. The CAT also needs a 5 volt supply line, but if you are using an arduino you can then get it there. Or you can use a 5 volt regulator (say a 7805) off of the 24 volt supply to the the 5 volts.
Kevin, a 555 circuit would work also
TheFishMan65
New member
Apparently the folks are Steve's LEDs use the CAT4101 (another RC said they got a board). Apparently they dim all channels at one time. They do this by using a sense resistor for each CAT (they sell a 4 board version) and then feed all those signals through a common potentiometer and then to ground. Not only this apparently the pot is a panel mount variety and goes to a connector on the board - nice kelvin connection . I had thought of doing something like this, but worried about interference from one CAT to another. So any design comments?
. I had thought of doing something like this, but worried about interference from one CAT to another. So any design comments?
Gorgok
New member
Do they ship from the reserve stock or is the cart right and they are simply out of stock? I would have quoted that price but i figured if its not really 'available' then it doesn't really count.
