Which hardware for your home automation project?

Which hardware for your home automation project?

When it comes to home automation there are a tremendous amount of solutions to pick from. Picking the right one could be a tough job. Therefore I made a shortlist for the most important features:

  • Affordable price — if you need many sensors it all adds up
  • Can read wireless sensors — I am unable to wire every device
  • Extendable — you never know what you want next
  • Wide range of sensors / switches supported — perhaps a sensor is not available anymore in the future
  • Energy efficient — most will run 24/7

Home Automation server

I needed a computer to run the home automation software. This computer will run  24/7, so energy efficiency would be nice. To process some sensors and run a database to show energy usage is not quite CPU intensive. Combined with my wish to stay affordable, the Raspberry Pi was a very interesting option. This computer is tiny, cheap, has GPIO pins to connect a LCD screen or custom sensors (more about this in a later post). Out of the box the Rpi lacked one important option: communicating with wireless sensors, especially the 433Mhz ones. More about this in the next paragraph.

Please keep in mind WIFI is not supported out of the box when you have a Rpi1 or Rpi2. The Rpi3 has WIFI and even Bluetooth out of the box.

When ordering a Rpi make sure you but at least a 2.0A adapter, otherwise it does not provide enough power to use USB peripherals.

Raspberry Pi 2 Model B
Raspberry Pi 2 Model B

433Mhz usb transceiver

After some research it turned out the cheapest devices are using 433Mhz to transmit and receive data. This goes for doorbells, temperature / humidity sensors, motion sensors, light switches. One thing to notice is 433Mhz devices are often used for one way communication. This means for example a KaKu socket can receive a signal on 433Mhz but does not transmit a confirmation signal when it actually switched. For this two-way communication you can use Zigbee or Z-wave, which is more expensive.

It turned out the way to go was to use a USB to 433Mhz transceiver. The one used by most home automation enthusiast is the RFXtrx433E USB 433.92MHz Transceiver. While some consider it a expensive device (€ 109,75), it definitely is worth its price. The transceiver supports an extensive range of devices. Another nice feature is the free firmware updates which add support for new hardware. Keep in mind that the latest version of the device is the 433E, sometimes second handed 433 devices (without the E) are for sale which support less devices.

RFXtrx433E tranceiver
RFXtrx433E tranceiver

Also worth a look is the table below taken from chapter 2.4 in the manual it shows the Sensitivity influenced by enabled protocols. While the transceiver supports a wide range of protocols some can not be used together. It is worth to check this table before you buy your hardware.

 Sensitivity influenced by enabled protocols
Sensitivity influenced by enabled protocols

To give you an impression of the sensors and devices supported by the RFXtrx433E USB 433.92MHz Transceiver I’ve copied the list from the rfxcom website.

Sensors

  • Cent-a-Meter, Electrisave, OWL power and watt meters
  • Alecto, Cresta, FineOffset, Hideki, Honeywell, LaCrosse, Meade, Oregon, Proove, Rubicson, TFA,Viking weather sensors
  • Alecto, Avidsen, Chacon, NEXA, Flamingo, Blyss, Proove smoke detectors
  • Atlantic, Chuango, Eminent, Meiantech, Visonic, X10 alarm sensors
  • Oregon scale,
  • Maverick, Rubicson BBQ sensors
  • Chacon, HomeEasy, KlikAanKlikUit, NEXA, X10 remotes.

Devices

  • ANSLUT, Avantek, BBSB, Blyss, Brennenstuhl, Chacon, COCO, Conrad RSL, DI.O, ELRO, Energenie, Eurodomest, Everflourish, Flamingo, HomeConfort, HomeEasy, Impuls, Intertek, Intertechno, Kambrook, KlikAanKlikUit, LightwaveRF, Livolo, Mercury, NEXA, OTIO, Phenix, PROmax, Proove, RisingSun, Sartano, Siemens, X10, XDOM dimmers and switches
  • 1byOne, Byron SX, KlikAanKlikUit, Profiles, SelectPlus doorbell,
  • A-OK, ASA, BOFU, Brel, Chamberlain, Confexx, Ematronic, ESMO, Hasta, Louvolite, Quotidom, RAEX, Rohrmotor24, Rollertrol, Simu, Somfy, Yooda blinds
  • Harrison, Forest curtainmotors,
  • Kingpin, Media Mount, Proluxx projection screens,
  • Avidsen, Chacon, NEXA, Flamingo, Blyss, Proove smoke detectors and sirens
  • Mertik Maxitrol fireplace
  • Aoke relais
  • MDREMOTE LED strip controller
  • Smartwares heating crane

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