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Control I2C Relay device from longer distances

Derby

New Member
Thread starter #1
I need to Control I2C Relay device switching with 2 ESP8266, As I have to use wired connection and control the relay from 40 m distance from every ESP8266.

According to some suggestion, I should be using I2C extender but how much far we can use these extenders and is there any other way also to control with ESP8266 through wired connection ?
 

Nigel Goodwin

Super Moderator
Most Helpful Member
#3
Use a better relay device, that is stupidly expensive and completely the wrong idea for what you're trying to do. I2C is essentially for connecting between IC's on the same PCB, trying to do long distance is a crazy idea.

Here's an 8 relay board for very little money, and along with a cheap PIC you could easily do the job via a serial interface (RS232 type), you could even use a current loop if need be.

https://www.banggood.com/5V-8-Channel-Relay-Module-Board-For-Arduino-PIC-AVR-DSP-ARM-p-74110.html

Is there some reason you can't have the ESP near the relay board?, after all the whole point of the ESP is that it's wireless.
 
Thread starter #4
Even this differential i2c can only go 3m

https://www.nxp.com/products/analog...-i2c-bus-buffer-with-hot-swap-logic:PCA9615DP

Might need an mcu on each end to interpret with rs485 in between.
Hi, it is like a secondary circuit in which both the controller are performing their function and if by which one controller might get affected or not working then another controller will work on behalf of the 1st one.

Use a better relay device, that is stupidly expensive and completely the wrong idea for what you're trying to do. I2C is essentially for connecting between IC's on the same PCB, trying to do long distance is a crazy idea.

Here's an 8 relay board for very little money, and along with a cheap PIC you could easily do the job via a serial interface (RS232 type), you could even use a current loop if need be.

https://www.banggood.com/5V-8-Channel-Relay-Module-Board-For-Arduino-PIC-AVR-DSP-ARM-p-74110.html

Is there some reason you can't have the ESP near the relay board?, after all the whole point of the ESP is that it's wireless.
Thanks for the suggestion but I am looking for the advice where I 'll use MCU on the endpoints only rather than using in between
But I am interested to know about current loop suggestion which might help me in the solution, I am looking for.
Can You please share me some advice with some block diagram which helps to clears me the concept of using it with both controllers as well as the wireless sensor?
 

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