QuinLED Diff-Adv Adding a relay to the mix
Idle power draw, 2 problems
Idle LED ICs
Digital LEDs still use power even when not displaying anything, this is because each LED or group of LEDs has a little tiny IC connected to it and even if there is no light output, this tiny little IC controller needs to stay alive to receive and process data for when the LED does need to be turned on.
Especially on installs with a lot of LEDs or rather ICs online this idle power draw can become significant.
Idle large PSU
Another factor to this is large PSUs, especially if you get some cheaper PSUs that output lots of Amps, their idle draw can easily be 15w or even higher.
Combined idle usage
On a larger install with say 3 of these big PSUs and 2000 LEDs this idle draw can become bothersome (say 100w) since especially during the day, there is no reason for this power usage, things can just be off all the same and use no power.
The solution to the above issues is adding a relay in front of these large PSUs on the AC side, cutting it off together with the LEDs and thus you’ll have no idle draw from those. You do still need to have a way of turning these on remotely though and that’s what this article is about, you can replace that large idle draw with something around 1w to make sure you can turn it on again remotely.
Why no vEXT function on the Diff-Adv boards?
Sadly it was not possible to integrate vEXT functionality on the Diff-Adv boards in a way that would make sense.
- For the Receiver-Midpoint-1 you only have 1 data channel coming in so that’s the LED data, no other signal available to turn on/off the relay
- For the Receiver-Midpoint-2 you do have 2 data signals coming in so one could be the on/off for the large power supply. But this would make the board a lot less useful and I decided not to add the costs to every board to integrate this.
Solution: Use a separate Receiver-Midpoint-1 to control a relay at the receiver end
The solution then is to use a separate Receiver-Midpoint-1 in the locations where you want to control a big LED PSU. This Receiver-Midpoint-1 would use a simple cheap phone charger (5v 2A model recommended) and consume only 0.5w max all the time. You’ll also need a 5v compatible relay like the ones listed in this article.
If you do this on the same chain of UTP cables you can dedicate a single channel for this control and still have 3 left for your LED data. The on/off command to the relay will be sent to each location at the same time when those boards are set to the same channel. Or you can use a separate Sender-4 and UTP cable to run along with the other UTP cable that carries all your LED data but this of course requires 2 cables to every box.
Below is a diagram of how this would look for running 3 LED data channels to 3 spots, each with also having a relay on the local PSU.
How to configure in WLED
To configure in WLED you really don’t need to do anything special, you just need to configure which pin of the board you are using you connected to which channel on the Sender-4 that you want to use as the “relay channel”. You do this in Settings -> LED preferences and then scroll down a bit below the LED channels to the relay output.
In our example we used a Dig-Octa with 4 connections and we’ll use the 4th LED output as the relay channel. Looking in the Pinout Guide for the Dig-Octa we see that we need to setup GPIO3 as the relay output in WLED.
Then, on all the Receiver-Midpoint-1 boards that have the relay connected, you setup those boards to pair-4 (as that is where LED4 of the Dig-Octa is connected to on the Sender-4). Once done, anything that is listening on pair-4 will switch on and off it’s data output whenever WLED performs it’s power and thus relay on/off function.