Lessons learned - First year

After a year I will say I have gained some experience in the field of DIY IoT and home automation. The first lesson is that it's not easy to plan what you want and actually go for it. Things and desires change on the way to the goal. I started with a Tellstick Duo, but I feel I outgrew it.

I came to a point where it no longer could do what I wanted it to do. Or maybe it was what I thought it could do. At first, when I had just a few sensors and switches, it could actually do what I wanted. But after a little under a year, I wanted to do more, and the Tellstick could no longer deliver. The most obvious is that it's not supported by the most used home automation software out there.

Several systems

Another thing I soon released was that DIY IoT and home automation system soon consisted of several systems, working more or less together. I had my API running on Linux and the Tellstick control running on Windows. It soon became a mess to administer, and I had to manually check that everything worked according to plan after every reboot. And reboots came almost every Tuesday when Microsoft updates came. I had to get rid of Windows to make a more robust and autonomous system. So I ditched the Tellstick Duo and went for a 433MHz RFXCOM RFXtrx433e USB tranceiver, supported by most home automation systems.

Radio frequency

Relying on radio frequency (RF) was/is also a challenge. Due to the low output power of sensors, it's not always a success when it comes to delivery. I have to place my sensors strategically to make sure the signals reach the receiver every time. I have not succeeded in doing that yet. Walls, floors and other obstacles will degrade any RF signal. Very often the receiver is not able to pick up the signal. I have noticed that this happens when the humidity is very high, usually around and over 50%. And my front door magnet sensor is unable to reach the receiver every morning when I get out the door to get to work...!? The rest of the day it seems to manage just fine, but also some glitches here.

A single system

As of now I have two receivers. One Moteino gateway for temperature, humidity etc. and one RFXCOM for PIR sensors and door magnet. The RFXCOM is also used to switch heat and light on and off. The RFXCOM transmitter works as it should every time, due to the slightly higher RF output signal. I now have everything connected to a Raspberry Pi, running DomotiGa to read all sensors and control heat/light switching. Now I don't need to check if everything is working after a reboot. It just works. And that's how it should be.

Conclusion

  • Windows is not a good choice when it comes to IoT and home automation.
  • Try to make everything run on the same box.
  • Try to avoid having several systems. What you want is one system that is able to do it all.
  • Check how well the receiver is able to receive signals.
  • Try to make the system small enough so it's easily moved from one room to another.

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