This page explains how we can build a cheap home automation system with the help of a Raspberry pi or Orange PI, an RF-link Gateway and a domotica set sold at many warehouses i.g. the Action.
This system is compatible with many home automation sets, i.g. Klikaan-klikuit (COCO), Home-Easy, etc.
The main components are a Raspberry-like arm board and an arduino mega2560 with a receiver and a transmitter connected.
How does it work? The system reads the remote from the domotica set and configures a switch automatically. This switch can be controlled from the internet. You can also configure timers for the switch to automatically switch a lamp on/off at a certain time / date / day or an event like sunset. This system has an amazing amount of capabilities a.o. it can read sensors like weather station, wireless doorbel, doorcontacts and can react on ocurrences i.g. when a door is opened, it can send an email, sms or pushover notification and/or put a lamp on for a certain time.
What do you need fo a start.
* a Raspberry PI or Orange PI lite/Zero (OPI).
* a case and a power supply for the Raspberry/OPI
* an SD card of 4Gb
* linux and Domoticz installed on SD-card.
* an Arduino Mega2560 (clone)
* an RXB6 433Mhz Superheterodyne Receiver module.
* an STX882 ASK 433Mhz RF transmitter module.
* some wire.
I replaced the Raspberry PI with a much cheaper Orange PI lite which has a wifi module on board. You can buy it at aliexpress. This also works with the Orange PI Zero. The mega2560 is a chinese clone bought on ebay, as well as the transmiter and receiver. The total does'nt exceed 40 Euro
The RFLINK GATEWAY is simple to build, you need 6 pc of wire, the transmitter and the receiver modules and you have to install a firmware on the mega. For information on the RFLINK GATEWAY you can visit nemcon.nl/blog2 or google for it. There is a.o. information on what transmitter/receiver give the best results.
The transmitter i applied works on max 3.8 Volt so i had to make a voltagedevider with three resistors. In the dataline i placed 2 diodes in series, they provide a voltage drop of 1.2Volt.
Also the antenna needs special attention. I found this instruction on the internet: https://www.elektor.nl/Uploads/Forum/Posts/How-to-make-a-Air-Cooled-433MHz-antenna.pdf
I printed a case for the gateway, so you also need a 3d printer but thats only a small detail.....
Conlusion: This system works realy good. The receiver i used receives the remotes and the temperature sensors from a considerable distance. No antenna is needed.
The reliability of the sensors depends on their position regarding to the transmitter. Behind a large tv-set is not always a success.
Without obstacles a distance of 10 meters is achievable, maybe more but i can't test that.
Also the differend brands give differend results, the set from the "action" listens to the off signal but i can't
get it on from a distance more than 7 meters. Although it listens to the remote.
Another set that i bought at Lidl some years ago works much better. So as to the transmitter some improvements seem possible.
Maybe we can disassemble the transmitter from a remote and use that in the RF-link gateway ...
Today i found a set on ebay: 433MHz-100-Meters-ASK-Module-Kit-RF-STX882-Transmitter-SRX882-Receiver-Antenna. 100mtr, this seems promising....
Update 10-dec-2016: I build an improved version of the gateway with another transmitter, from the earlyer mentioned set. I loaded it with the latest firmware R45. The transmitter has a short antenna.
The results are very good. The rf-link gateway now can completely replace my expensive rfx-com transceiver.
Works with Silvercrest set from 'Lidl', cheap set from 'action', KaKu, HE, X10, Conrad rsl, all without issues and from considerable distances.
On the OPI i installed an Armbian Jessie linux system. This has no user interface so you have to configure your wifi network first by connecting an USB keyboard and an HDMI monitor or tv. Now you can edit /etc/network/interfaces and give it the following content:
The address of your router may be different so may you have to edit the numbers!! By doing this you configure a static network which has many advantages, especially when you want to reach it from outside your network.
Once this is done (reboot first) you can connect to the OPI by opening a terminal on the IP address using "Putty.exe".
Although not really necessary i installed a "lamp" server and a samba server. The most important software here is Domoticz, google for installation of Domoticz on a Raspberry PI.