SparkFun Forums

[Tarik41]

Hello everybody!

I would like to make a project that consist of a microcontroller or MCU (Master), and four groups of I2C Devices, each group have from 0 to 3 devices.
The problem is that each group should be a little bit far from the MCU, lets say 15 meters as maximum distance. Because I2C cannot go that range on itself, an other protocol has to be used, I am thinking of either the RS485 or Ethernet. As seen on the figure/image below.
Can someone please tell me what components do I need to build this circuit ? Something like:

1. A Device/Module that take I2C from MCU as Input and output many I2C fixed addresses as output (up to 12 address in the image below).
2. A module to convert I2C to Ethernet RJ45.
3. An RJ45 cable of 15 meters
4. An RJ45 to I2C module
5. I2C Slave devices (Bidirectional communication is mandatory)

Any idea is helpful.
Best regards

Attached image url: https://imgur.com/a/9LcbDtQ

[jremington]

I would use Arduino Pro Minis to locally control the remote I2C devices, with multidrop RS422 or RS485 adapters on cat5 cable. Power can be transmitted over the cable, too. Some suitable protocol must be developed to allow the master node to control a remote node, with its devices.

If speed is not an issue, then you probably don't need the RS485 adapters, as ordinary TTL level serial can easily be used over 15 meters at low (e.g. 2400) Baud rates.

[Tarik41]

I would use Arduino Pro Minis to locally control the remote I2C devices, with multidrop RS422 or RS485 adapters on cat5 cable. Power can be transmitted over the cable, too. Some suitable protocol must be developed to allow the master node to control a remote node, with its devices.

If speed is not an issue, then you probably don't need the RS485 adapters, as ordinary TTL level serial can easily be used over 15 meters at low (e.g. 2400) Baud rates.

Thank you for that