Last Updated or created 2025-10-27
We are planning to redo our garden. And I am making a water and light plan for it.
I thought I could do it myself using 12V and RS485/Modbus.
So these are my plans. (NOTE, this is a work in progress)
I’m going to put 4-wire ground cable in our garden, and a RS485/Modbus master controller in my shed.
4 Wires will have 12V low voltage, ground and RS485 A/B wires.
This way I can control till 64 devices on a single cable.
Below, a USB stick to connect the RS485 cables to a Raspberry Pi?
Software is probably going to be a NodeRed instance connected to Home Assistant.
On/Off lights using a RS485 board and relay. These can be bought on a single PCB and can control 220V. I am probably going to use generic outside lamps and refit them for 12V led or 220v, with those RS485 controllers.
The above left part will be encased in resin or alike.
Right PCB is for testing only.
For dimming RGB lights, I made the below design.
12V to 5V using a 7805, RS485 8pin DIL/DIP and a ATTiny85 8pin DIL/DIP. Plus a 4×4 RGB Matrix.
These also encased in resin.
More information on the ATTiny85 and programmer can be found here:
Modbus using NodeRed (I’ve used this to control my RD6006 Lab Power Supply)
