I recently discovered the ESP8266 module, it comunicates over serial and you can flash it with custom firware like the arduino bootloader. The module is insanely cheap and realy versatile due to the replacable boot code.
Nagging about the old setup
The reason I started this project is the need for a more reliable relay connected to my domoticz home management system. Before this I was using 433Mhz based relays, at first just bit banging commands over to a 433Mhz transmitter and later with a RFXtrx433E. When I got any of these to work I was just relieved it did as expected and pretty happy with the results. After a while though the cracks started to show, everything has a noticeable delay and you cant send out commands too fast after each other or recievers will simply not react.
I did a bunch of other projects based around MQTT pub sub systems and know for a fact if is fast, reliable and posible to run on a embedded devices.
I found a open source project that uses those techniques together with domoticz or openhab.
Later more on software and config
My first home made wifi based multi relay
In the last part of this spost I'll list some of the hardware items used to create this device.
|Part||Function||Qty needed||Cheapest offer||Seen at|
|ESP8266||Wi-Fi + microcontroler||1||€1.69||Aliexpress|
|Breakout board||2mm -> 2.54mm pins||1||€0.16||Aliexpress|
|2.54mm stackable pin headers||Socket for the ESP||4x 8pins||€0.24||Aliexpress|
|SRD-05VDC-SL-C T73-5V 10A||High voltage relay||2||€0.60||Aliexpress|