hey folks
I have a 4 channel relay as shown below and i want to be able to on/off each of them wirelessly using 4 push buttons with the least expense. I’ve looked at using espnow, rf module , nrf but they all need microcontroller to work. I want to know of a solution without using a microcontroller or if using a microcontroller then at the cheapest method.
How about something like this?
espnow will work 
There are devices like this remote available:
https://robu.in/product/wireless-four-button-remote-control-module/
But you would probably have to develop a logic circuit which can toggle based on the pin which changes state based on the button press.
If this is something you are looking into.
For cheapest option something like this might work. https://electronicspices.com/product/27mhz-4ch-rc-car-remote-control-circuit-pcb-transmitter-and-receiver-board-with-antenna
But the problem with these toy car modules is that output is momentary, the output will be high as long as the button is pressed, on de-press the output will turn off.
So additional circuitry would be needed to create a holding circuit. Something that turns a pulse into a toggle signal.
Something like two CD4013 chips, which are cheap, 2 inputs 2 outputs per chip. The pulse signal from RX module will be fed into the CD4013 and output from the CD4013 will go to your relay.
You have to combine your order for the minimum price.
Google CD4013 button to toggle switch circuits.
I will post something later, if I find something even more cheaper.
You will have to explain your use case a bit so as to get appropriate response.
NOT A WIRELESS OPTION: still, if esp 8266 / esp32 are costly to control, you may try ttp223 touch switch modules to activate and deactivate them. They work well and may cost below Rs 10 /- per module. (please note that you may have to solder to enable this mode in ttp223).
Wireless option may include esp01 8266 might cost between 110-150/- but this will require you to purchase a USB to serial adapter for flashing
Using these components, all available on robocraze.com
1x RF Wireless Module Pair (433MHz)
1x HT12D Decoder IC
1x HT12E Encoder IC
2x CD4013 Dual D Type Flip-Flop IC
4x 10k resistor
1x 1M resistor
1x 47k resistor
4x Push buttons
2x Vero Board (PCB)
Wires and soldering equipment, I guess you already have.
Total Cost
Connecting them like this.
In place of Leds the output will go the 2 CD4013 ICs and from there it goes into your relay board.
1 CD4013 has dual independent D flip flop, so following circuit will be replicated 4x times. Twice on each CD4013.
You could just use 2 esp8266s, they’re pretty cheap.
if push buttons are not necessary, even 1 esp with mobile app would work
The transmitter should be battery powered as it will be placed on a wall next to the computer and esp8266 are power hungry. Is esp now the same as wifi ?
espnow would be ideal for the controller in that case,
I haven’t built anything myself but have used an esp32 based espnow remote from phillips.
Its called the wizmote for reference
