I'm in full swing making a LED fixture for a saltwater aquarium.
I got a hold of a couple of 3W Common anode RGB LEDs and looking to control them via and Arduino mega 2560 and 3 meanwell ldd 700L drivers. I'm having some problems figuring out how to connect this up.
I understand the concept of how you put a higher voltage (pwm signal) at ground to reduce each channel, but it is possible to use the LDD drivers positive towards ground on the LED. I'd rather not burn my driver's and possibly my Arduino
It see how lower power LEDs can be connected to the pwm outputs directly and with a currentlimiting resistor, but is is possible to daisy chain 10 of those 3.4v 700mah LEDs together with LDD drivers and 36v PSU?
Oskarw90:
I got a hold of a couple of 3W Common anode RGB LEDs and looking to control them via and Arduino mega 2560 and 3 meanwell ldd 700L drivers.
Which ones. Post a link
3watt RGB could be 3*1watt LEDs (330mA LED current).
Oskarw90:
I understand the concept of how you put a higher voltage (pwm signal) at ground to reduce each channel, but it is possible to use the LDD drivers positive towards ground on the LED.
Don't fully understand this part.
LDD drivers can be controlled two ways. Linear voltage and PWM.
PWM from a Mega (5volt PWM) is fine.
Just connect LDD ground to Mega ground, and LDD input to a Mega PWM pin.
Oskarw90:
It see how lower power LEDs can be connected to the pwm outputs directly and with a currentlimiting resistor, but is is possible to daisy chain 10 of those 3.4v 700mah LEDs together with LDD drivers and 36v PSU?
No resistor needed between PWM output and LDD input.
Only RGB LEDs that have 6 pins can be connected in series.
700mA is ~2.3watt per LED, but as said, they could be 1watt per colour.
The LDD needs some overhead voltage (>=3volt), so 36volt for 10 ~3.3volt LEDs might just be enough.
Leo..
No practical experience in fish tank lighting, but I think single colour 3watt LEDs on a star base are more commonly used there than RGB LEDs. Then you also can choose the specific colours you want (royal blue?).
Maybe ask on an aquarium site.
A PCA9685 breakout board (Adafruit, ebay) could be used to drive your LDD modules.
The advantage of that is smoother 12-bit dimming, up to 16 LDD modules per board, and only two Arduino pins used. Post#10 here shows a home-grown 16-channel LED driver board (16 LDD modules) with PCA9685 and onboard ESP-12 (Wifi/webpage control, RTC, etc.), including 3.3volt supply.
Only needs a 24volt supply and the 3watt LEDs (~100), nothing else.
Leo..
Wawa:
No practical experience in fish tank lighting, but I think single colour 3watt LEDs on a star base are more commonly used there than RGB LEDs. Then you also can choose the specific colours you want (royal blue?).
Maybe ask on an aquarium site.
A PCA9685 breakout board (Adafruit, ebay) could be used to drive your LDD modules.
The advantage of that is smoother 12-bit dimming, up to 16 LDD modules per board, and only two Arduino pins used. Post#10 here shows a home-grown 16-channel LED driver board (16 LDD modules) with PCA9685 and onboard ESP-12 (Wifi/webpage control, RTC, etc.), including 3.3volt supply.
Only needs a 24volt supply and the 3watt LEDs (~100), nothing else.
Leo..
Thanks!
I'll definitely check it out!
Yeah the RGB LEDs are only for adjusting the colour temp for Dawn and dusk. I have around 70additional 3w LEDs (royal blue, 15kK, green, UV, etc.etc ) and 5 30W ones
otherwise I would draw up the diagram!