LED algea scrubber DIY
- Thread starter UnderWaterDiver
- Start date
No, but I can make some on a different thread later (tomorrow). I don't want to hijack this one any further.
Hi,
I will be happy to update the thread soon, this weekend i am a bit busy so i think maybe next week.
I did not try other LED combinations. What i have now does do the trick for me.
LED's are more expensive i guess, but then again you don't have to replace them for a long long time....
And i don't have 220V that can zap me when i have one hand in the tank and the other hand on the light (by accident) .. he he..
I will be happy to update the thread soon, this weekend i am a bit busy so i think maybe next week.
I did not try other LED combinations. What i have now does do the trick for me.
LED's are more expensive i guess, but then again you don't have to replace them for a long long time....
And i don't have 220V that can zap me when i have one hand in the tank and the other hand on the light (by accident) .. he he..
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yeah but if you only put your hand 1/2 way in it'd only be 110 and that's just a tingle.
Hi All,
I will add some more info about the LED's power source and cooling tonight.
I selected 8 LED's, so i had to find a way to power them.
At first i planned to power them one by one each having it's own regulator. For this i experimented with linear rectifiers, like the LM317.
The idea was that i could then control each LED individualy.
I would provide 5 volt and then set some resistors on the LM317 to regulate it down to the 3.7 volt. The LM317 (TO220) can drive 1.5A so that would work. I tried it and yes it works, but as linear rectifiers go they convert the voltage drop (5v-3.8v=1.2V) into heat.
And heat is lossed energie.
Another "problem" with above method would be to find a power source that can deliver 5V at at least 8A (8 Led's each need about 1 A).
I checked my favorite website where i can buy electronics but the price for such a power supply where way to high.
So i decided not to go that way.
First i needed to find a cheap and reliable power source. So i got the idea to use a cheap ATX computer supply. i found a new one for about $15 that was rated at 350W.
The ATX power supply has to following output voltages and maximum currents:
3,3V (30A)
5V (22A)
-5V
12V (20A)
-12V
I could use the 5V but then i would need to use e.g. the LM317 to drow the voltage to 3.8V for my Leds.
I could also use the 3.3V. But when i checked the light output of the LED at the reduced voltage of 3.3V that was not very good.
So i decided to go with the 12V. And put 3 Led's in series.
Each LED would then get 4V which would be absolute max rating.
Now when i tried this my power supply did not produce exactly 12V but a little less, so in the end each led ended up with 3.8V.
Because i made my setup with 8 Leds and not 9 i needed to put some resistors in the other 2 LED's so i used 2 10Watt resistors of each 1 Ohm
to drop the voltage. So i ended up burning away some heat on these 2 resistors that if i build it again next time will be put to better use on a ninth LED.
So the setup is to use 3 strings of leds. String 1 and 2 both having 3 leds in series and string 3 two leds in series with the 2 1Ohm 10W resistors.
To use a ATX power supply you need to know a little trick so it turns on out side of the computer. When the supply is plugged in in the mains. it always draws a little current but is not fully on. It is in sleep mode.
To turn it on you need to short pin number 14 to ground, e.g. to pin 13.
See http://wiki.xtronics.com/index.php/ATX_Pinout
like this:
So with this cheap ATX power supply i can drive a lot of LED's.
As indicated previously each LED must be cooled. For this i bought some
heat sinks that i think are normaly used on the PC's mother board's chips.
Each costs about a dollar, and as bonus they have a heat conductive
sticker. So all i needed to do is stick the LED's on this sticker and firmly press it.
I now have this setup running for several months ( i think 4-5) and i did not lose any led's (burn up) or from disconnecting from the heat sink.
next time i will post some pic's about the algea i harvest every week.
and some more details about the construction of the "waterfall"
i redesigned that since the first pictures, i now use some black plastic and somebody cnc-ed some parts of that plastic for me...
I will add some more info about the LED's power source and cooling tonight.
I selected 8 LED's, so i had to find a way to power them.
At first i planned to power them one by one each having it's own regulator. For this i experimented with linear rectifiers, like the LM317.
The idea was that i could then control each LED individualy.
I would provide 5 volt and then set some resistors on the LM317 to regulate it down to the 3.7 volt. The LM317 (TO220) can drive 1.5A so that would work. I tried it and yes it works, but as linear rectifiers go they convert the voltage drop (5v-3.8v=1.2V) into heat.
And heat is lossed energie.
Another "problem" with above method would be to find a power source that can deliver 5V at at least 8A (8 Led's each need about 1 A).
I checked my favorite website where i can buy electronics but the price for such a power supply where way to high.
So i decided not to go that way.
First i needed to find a cheap and reliable power source. So i got the idea to use a cheap ATX computer supply. i found a new one for about $15 that was rated at 350W.
The ATX power supply has to following output voltages and maximum currents:
3,3V (30A)
5V (22A)
-5V
12V (20A)
-12V
I could use the 5V but then i would need to use e.g. the LM317 to drow the voltage to 3.8V for my Leds.
I could also use the 3.3V. But when i checked the light output of the LED at the reduced voltage of 3.3V that was not very good.
So i decided to go with the 12V. And put 3 Led's in series.
Each LED would then get 4V which would be absolute max rating.
Now when i tried this my power supply did not produce exactly 12V but a little less, so in the end each led ended up with 3.8V.
Because i made my setup with 8 Leds and not 9 i needed to put some resistors in the other 2 LED's so i used 2 10Watt resistors of each 1 Ohm
to drop the voltage. So i ended up burning away some heat on these 2 resistors that if i build it again next time will be put to better use on a ninth LED.
So the setup is to use 3 strings of leds. String 1 and 2 both having 3 leds in series and string 3 two leds in series with the 2 1Ohm 10W resistors.
To use a ATX power supply you need to know a little trick so it turns on out side of the computer. When the supply is plugged in in the mains. it always draws a little current but is not fully on. It is in sleep mode.
To turn it on you need to short pin number 14 to ground, e.g. to pin 13.
See http://wiki.xtronics.com/index.php/ATX_Pinout
like this:
So with this cheap ATX power supply i can drive a lot of LED's.
As indicated previously each LED must be cooled. For this i bought some
heat sinks that i think are normaly used on the PC's mother board's chips.
Each costs about a dollar, and as bonus they have a heat conductive
sticker. So all i needed to do is stick the LED's on this sticker and firmly press it.
I now have this setup running for several months ( i think 4-5) and i did not lose any led's (burn up) or from disconnecting from the heat sink.
next time i will post some pic's about the algea i harvest every week.
and some more details about the construction of the "waterfall"
i redesigned that since the first pictures, i now use some black plastic and somebody cnc-ed some parts of that plastic for me...
Last edited:
Thanks for that writeup UnderWaterDriver on the computer power supplies. I have used them in the past to run fans and such on my tank because I am a computer geek and have a ton of them laying around, but never wrote up a instruction sheet like you did explaining how others could do it. Good job!
