Little bit of Hardware

Few weeks later …

I had some days off to do something real πŸ™‚ this time – but first things first. I’ve recently started a little hardware project which allows me to gather some environmental metrics like: air humidity, atmospheric pressure, temperature and light brightness. I just made some kind of personal meteo-station to be integrated with my Home Automation System based on PLC. Since my infrastructure is based on PLC I had to connect “this thing” somehow to the PLC itself. Since the easiest way to do it was the MODBUS RTU over RS485, so I’ve implemented simple MODBUS RTU slave device using old good (reliable) RS485. So, now I have functional prototype based on ATmega328 Microcontroller with following features:

  • atmosferic preasure [hPA] measurement – based on Bosh BMP180 i2c sensor allows to measure pressure with great accuracy
  • humidity [%] measurement – based on Honeywell HIH6000 i2c sensor – accuracy +/-4.5%RH
  • temperature [C] measurement – based on old good Maxim DS18S20 1-wire sensor
  • light brightness [%] measurement – based on analog foto-resistor sensor
  • configuration of the module via USB – no need for jumpers, microswitches etc. Just plug the device via USB and use any terminal to setup MODBUS RTU SlaveID and RS485 link speed
  • data transfer via MODBUS RTU using Read Registry function – for integration with my PLC controller
  • 12-24V voltage range for easy connectivity with various power sources

You may ask why I did it. Well, besides the obvious reason (fun), I want to present gathered data in IQarium. So, stand by – upgrade comes up πŸ™‚
By the way, I’ll have some extra PCB from manufacturing plant, so If you are interested drop me an e-mail I can make a quotation for you. If you would like to see how the prototype works then add the comment below, it will encourage me to make the video.


One thought on “Little bit of Hardware

  1. Can’t wait for the updates. I bought an modbus RTU weather station, so I’m very interested how you put it all together.

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