OpenEnergyMonitor Community

Linknode R4 Wifi 4 Ch Relay Board


Has anyone tried to use the LinkNode R4 Wifi board using the ESP8266 chipset.

I’m looking to control it via Emoncms on my under floor heating with 1 channel to switch on the pump and the others to switch on the zones. It has HTTP control so I guess I can use the CURL widget or possibly MQTT if its enabled.

I love the Openenergy WiFi Relay I have, but the cost to get 3 channels is a little expense compared to this unit.

Thanks in advance.

You should be able to upload martin’s 3CH relay code with some modifications change the pin numbers to control the relays.

Looks like a tidy board. Let us know how you get on.

1 Like

Only a tenner on Amazon (UK)

Any suggestions for the right power supply or USB to barrel cable? Getting the right barrel connector is often tricky. Nothing on the Wiki to suggest what it is. Why not just use a micro USB :confused:

1 Like

Looks like a good board, I was initially put off by the P&P at $90+ to the UK and only Maplin listed as a uk distributer, but @borpin’s find on uk amazon is good, I might order one to try.

I noticed all the power supplies on their shop site with a “barrel” connector seem to be “Center-positive 5.5x2.1mm barrel connector.” which is the same connector as the 9vAC supplies we use.

Wow, can’t argue with the price! Definitely needs a good enclosure if being used for mains voltage :dizzy_face:


Bit OTT? A secure plastic box should suffice I’d have thought.

I wouldn’t use metal pillars and metal screws to secure it in the box - plastic pillars or nylon screws yes (that’s the double-insulated bit, i.e. you don’t just rely on the PCB itself for insulation).

Of course, it doesn’t matter if you’re only switching SELV circuits, but my bet is, most people won’t be, it will be used mainly on mains appliances.

Ok the unit has arrived and powered up well.

Unfortunately I have become so accustomed to the high quality software on the open devices, I’m now learning quickly how to load the 3CH software to use the board which seems to be of a suitable build quality.

All points noted on safety and a good quality plastic box and correct sized fuse on the spur should be fine.

Watch this space on the next stages…

1 Like

Id be interested to see how you get on, for a tenner you can do lots at a reasonable price.


What are the board dimensions?

So after a few attempts I can control the relays only via the LinkSprite APP over the internet. No local access to the relays it would seem despite the IP address being available and all normal normal ports for http tried.

Size as you can see is about 3 inches square using the AA battery for comparison.

On the control side the normal operation is 1 relay at a time, however if you send 11111 to the board all relays will switch. So its R1 1000, R2 0100, R3 0010 and R4 0001 or any combination.

Next step is to see if I can load the firmware for Martins 3CH board when I get the Platform IO setup and find a copy of the build.

More to follow…

No longer available on Amazon UK - how many did you guys buy? !!!


Only 2 were available and I had one…

Sold out! I’ve got one coming tomorrow. :slight_smile:

5 posts were split to a new topic: Sonoff wifi-wireless-switch

So tonight I have upload a test ESP8266 WEBserver and WifiAP which all works, so first step completed.

I’m struggling to load the ZIP containing the 3ch relay example from Martin.

I’m using Arduino 1.6.12 on windows with OpenEnergy USB link all working fine.
Tried adding the zip as a sketchbook, library and took a look on many sites, but I guess it will be a simple thing that’s eluding me so all advice welcomed.


Have you had a look at this:

It covers installation via the Library Manager as well as installing a library manually.

No problem with those now.

So I have the ZIP file ‘ESP8266_Relay_Board-master’ with all its content etc and I want to now load this into Arduino and upload to my relay board.

Its not a library file as it fails to find files it needs, so its a step I’m missing I guess.

All other built in examples etc work fine here just cant get this particular one loaded.

Hope that makes sense…

A little more learning and the piece I’m lacking is the sketch that pulls it all together.

I was thinking that would be in the ZIP file but its not jumping out at me?

Loaded many other built-in examples no problem so just one small step away…