Electrical – home automation with arduino, raspberry using externally powered relay board

arduinoraspberry pirelay

I have a plan to put together small home automation system.

For now I was just playing with smaller parts like single type of sensors at once etc…
I would like to ask for opinion & check of my scheme if basic idea is ok, before I plug everything together.
I saw many variants of externally powered Relay Board, so I am little confused and I am not sure if its ok.

Basic idea is to see data & control everything from website
DHT sensors (read and display data on website graphs)

  • only DHT22 nr1 will trigger PC-FANs 1 & 2, when temperature or humidity is too high
  • PC-FAN (1 & 2): they run ON all the time (set time from … to …)
  • LED strip (1 & 2): they run ON all the time (set time from … to …)
    (LED strip has to be on separate power line since current A is to high for single relay)
  • Soil sensors (1-4) (read and display data on website graphs)
  • Water pump (1-4) each separately triggered for period of time when humidity in soil is to low (from Soil sensor 1-4)

Is my plan ok?
Any suggestions are welcome, thank you.

small home automation

Best Answer

I see a distance limitation problem. USB appears to be the link between the controller and peripherals. That puts about a 5 meter limit on how far away you can place peripherals. There are workarounds to extend USB (search for "usb extender"). But most use longer distance protocols such as C-BUS or RS-485.

In this thread someone posts the link to the people who designed and published C-BUS.

In this thread people are talking about connecting a Raspberry Pi to Arduinos using RS-485 and something called the Modbus library.