WoW ! Using a Relay Module without a Micro Controller
Channel: Sitges Villa Apartment, Neil Scott
Date: 2023-03-03

Here is a quick dirty one take video on how to use a relay module without needing a Arduino , Pi or other microcontroller.

WARNING it involves using high voltage AC so you do this at your own risk.

***********HIGH VOLTAGE CAN KILL YOU*************

This is not an instruction video, it details what I have done only . If you're not happy working with high voltage then consult an electronics or electrical technician. 

Well I could not find a definitive answer on how to use one of these without a controller like a Pi or Arduino and for what I wanted to do I didnt need one.

I wanted to install some fancy new LED Ring or Halo switches into a control panel on my CNC machine at home , the trouble is these switches only work at a current load of 2 amps which is far too low for my inverter, compressor and chiller.

I needed a relay but didn't want great big large SSR 's as there is no space in the unit for them. I saw these and thought I would have a go at experimenting with one because all the microcontroller does is to supply a small low voltage DC current to energise the coil in the relay when the code is run on it.

All you need to do is replace the microcontroller with a low voltage PSU and route that through the switchin my case to the relay, the switch acts as the microcontroller and allows the relay to energise and that allows the relay to function and switch the AC load on (max 10amps)  safely, it also means all the switches on my control panel are low DC voltage and the high voltage is safely inside the cabinet away from fingers or damp hands .

Its a standard way of working with commercial electrical installations on machinery, the switches are all mostly using a 24 DC voltage and the 3 phase nasty killer stuff is behind the relays where it should be so any work inside the main control panel is relatively safely carried out.

I have 6 x 12 volt LED Halo/Ring switches ,  basically on or off position only, one key operated switch and a momentary switch for pulsing making 8 in total, this relay module is 8 channel meaning 8 individual loads can be operated at any one time independent of each other.

The 12 volts PSU willsupplyenoughpowertolightall the LED rings and power on button and still have enough power to energise the relays.

The switches I have remain red when the key operated switch is turned and they turn to green when they are pressed. A quick glance at the control panel tells me what is running and what is not very quickly by colour.

In the video you will see a small 12volt DC PSU, run the positive and negative off that to the Relay board marked DC in,  then take an additional positive line from there and run that to your switch and on the other side of your switch take a line from there back to the Relay board and insert that into the "IN" channel for Relay number 1.

 You will find all the channels normally close to each other, either as pin headers or in this case small cable connectors which I prefer here. All normally marked as "IN 1 ", 2 3 and so on.

Keep in mind your PSU must have sufficient current to power all the LED switches as in my case red and green LED's plus the current for each relay and allow a little spare for any peak load .

This is all carried out on the low voltage side of the relay, however on the high voltage AC side all you need to do is run a one AC voltage wire into the common terminal on the relay from 220/110 Volt supply and then run the other AC wire in your circuit to either the NO or NC side of the relay depending on whether you want the AC circuit closed or open when the relay functions.

 In my case I want the circuit to function when I supply a voltage. You need to repeat this for every relay you want to function.

Always bare in mind that you must not exceed the 10amp limit per relay and allow for peak amperage if your running anything that needs a kick to get it going such as chillers, large extraction fans and so on. 

Note: If you need more than10 amps use a SSR and trigger it the same way, these boards tend not to go above 10  amps I have found and the LED switches also do not normally exceed than 2 or 3 amps on switching.

These relays come in single, double, four, eight and sixteen channels , make sure your wiring is safe, the relay is secure and there is adequate ventilation to cool the relay module.

Thats it really, It was great to find it works and now it means I get the control panel I want, later I will edit the video or redo it and put up a proper wiring diagram, at the moment I just wanted to share as I couldn't find an answer online about these relays. 

There are many types of these relay modules available, different DC input voltages from 3.3 volts to 24 volts DC.

Remember Boys and Girls, play safe and isolate the mains voltage until you're ready to test it and then when you are dont lift up the relay module in your bare hands, its got live voltage on the back of it !!!!!  

Neil , Olivella ,Espana. 
Marzo 2023.
#play_safe_always