LED build 10 gallon help?
- Thread starter pikachux3
- Start date
Is it possible to use a resistor to drop the voltage to the arduino like in this link?
https://donnie.co/aquarium/arduino-ldd.png
I do not understand the diagram above since I don't see how the arduino is powered without connecting via USB.
Here is my progress so far. It would be nice if I could just use one power supply.
You can use a resistor. Not ideal tho as that resistor is wasting energy to drop from whatever input voltage it has to get down to the voltage the arduino want. You could use a switching voltage regulator (lots around - google or ebay it for a look) which would be more efficient and not get so hot.
The arduino can be powered by its USB socket or by feeding 5V in to the pin labelled as 5V (the -ve goes to the ground (GND) pin).
Would you leave the power on all the time? If that driver board does not have pull down resistors on it, as soon as you turn the power on, your LEDs will come on at full power until the arduino has booted up and starts sending a valid PWM signal to the LDDs.
Tim
The arduino can be powered by its USB socket or by feeding 5V in to the pin labelled as 5V (the -ve goes to the ground (GND) pin).
Would you leave the power on all the time? If that driver board does not have pull down resistors on it, as soon as you turn the power on, your LEDs will come on at full power until the arduino has booted up and starts sending a valid PWM signal to the LDDs.
Tim
Would something like this work? And would I need one for each PWM signal?
http://www.ebay.com/itm/3-Terminal-5V-1A-Switching-Voltage-Regulator-Power-Supply-/261243604047
As for powering the arduino, do I also use a voltage regulator?
Do people leave the arduino on 24/7? Fortunately, the coralux driver board has a built in pull down resistor that turns the LEDs off in case of an arduino rebooting after a black out.
Thank you again Tim for answering my questions!
That voltage regulator looks tthe right sort of thing, yeah
Check the data sheet for the arduino tho, make sure you get a regulator tthat gives the voltage your arduino wants!
You don't use the regulator for the PWM signals - just to take the power from your LED power supply and drop its voltage down to a level the arduino is capable of using. The diagram you posted earlier with a resistor on? That was just adding a pull down resistor, similar to what's on your driver boards.
You just conect the input and ground of the regulator to the +ve and -ve of your supply. Then the arduino VIn to the output of the regulator and the ground to the ground/-ve from supply.
Tim
Check the data sheet for the arduino tho, make sure you get a regulator tthat gives the voltage your arduino wants!
You don't use the regulator for the PWM signals - just to take the power from your LED power supply and drop its voltage down to a level the arduino is capable of using. The diagram you posted earlier with a resistor on? That was just adding a pull down resistor, similar to what's on your driver boards.
You just conect the input and ground of the regulator to the +ve and -ve of your supply. Then the arduino VIn to the output of the regulator and the ground to the ground/-ve from supply.
Tim
Welp, I purchased a 7.5 gallon rimless. So new plans are
5x 3w Cree XT-E RB LEDs
4x 5w Cree XP-G NW LEDs
2x LDD-H 1000mA*
1x Coralux LDD-2 Driver Board*
1x Power Supply
1x Heat sink
For controller:
1x Arduino Uno*
1x LCD shield*
1x RTC*
1x 20-26 Gauge Wire
Items with * are what I have.
How does this look guys?
As for the power supply, I am not sure what to pick.
There are two strings: 5 RB LEDs will be on one driver and 4 NW LEDs will be on the second driver.
5 RB LEDS = 3.5 Vf * 5 = 17.5 Forward Voltage
5 NW LEDs = 3.15 Vf* 5 = 15.75 Forward Voltage
From my understanding, the two strings are in parallel due to the coralux board, am I correct? If so, I need to pick a power supply that is greater than 2A? Is a 24V power supply okay?
5x 3w Cree XT-E RB LEDs
4x 5w Cree XP-G NW LEDs
2x LDD-H 1000mA*
1x Coralux LDD-2 Driver Board*
1x Power Supply
1x Heat sink
For controller:
1x Arduino Uno*
1x LCD shield*
1x RTC*
1x 20-26 Gauge Wire
Items with * are what I have.
How does this look guys?
As for the power supply, I am not sure what to pick.
There are two strings: 5 RB LEDs will be on one driver and 4 NW LEDs will be on the second driver.
5 RB LEDS = 3.5 Vf * 5 = 17.5 Forward Voltage
5 NW LEDs = 3.15 Vf* 5 = 15.75 Forward Voltage
From my understanding, the two strings are in parallel due to the coralux board, am I correct? If so, I need to pick a power supply that is greater than 2A? Is a 24V power supply okay?
If the highest voltage string is 17.5V you need 20.5V (including 3V for the LDD). So that string needs 20.5W (voltage multiplied by drive current). The other string will be 18.75W using the same calculation. So, ideally you want 20.5V as your supply voltage. But I doubt you can buy that, so get one that gives a bit more and preferably can be adjusted (more voltage is OK, the LDDs will deal with it, but are more efficient if you give them the voltage they need).
Don't worry about the output current of the power supply, particularly. It just needs tto give the right voltage (at least) and have more than enough power. You need just over 39W, so go for a supply capable of 40 to 50W. You don't want to run your power supply flat out. I'd go for 24V 48W and that should do you fine
Tim
Don't worry about the output current of the power supply, particularly. It just needs tto give the right voltage (at least) and have more than enough power. You need just over 39W, so go for a supply capable of 40 to 50W. You don't want to run your power supply flat out. I'd go for 24V 48W and that should do you fine
Tim
If the highest voltage string is 17.5V you need 20.5V (including 3V for the LDD). So that string needs 20.5W (voltage multiplied by drive current). The other string will be 18.75W using the same calculation. So, ideally you want 20.5V as your supply voltage. But I doubt you can buy that, so get one that gives a bit more and preferably can be adjusted (more voltage is OK, the LDDs will deal with it, but are more efficient if you give them the voltage they need).
Don't worry about the output current of the power supply, particularly. It just needs tto give the right voltage (at least) and have more than enough power. You need just over 39W, so go for a supply capable of 40 to 50W. You don't want to run your power supply flat out. I'd go for 24V 48W and that should do you fine
Tim
Always so helpful, thanks Tim!
Most fans are 12V computer fans, so you don't really want to run them an 24V since that will either kill them or make them bluddy noisy (but if they survived, you can be sure they'd cool your heat sink :laugh: ). You need either a separate supply (cheap 12V or even 9V plug in mains adapter - 9V will still run most fans, but it'll run them slower and quieter which is great, so long as the heat sink is up to it with slower flow) or simply get a 12V regulator to run both the arduino and fans
Tim
Tim
