First step in implementing the home automation system is the monitoring part. This part consist in remote wireless nodes which send temperature and humidity measurements values to a central node made with RaspberryPi, where this values are recorded and processed.
These nodes will be built around ESP8266 wireless modules and can be configured to be sensors, actuators or both. On first phase, each node will have its role set from firmware loaded on it, future plans are to have same firmware loaded on all nodes and roles are assigned/changed on the fly from central node.
Central node will be built around RaspberryPi3 which is also the core of the whole system, where measurements are processed and actions are issued to actuators according to predefined scenarios. Also instantaneous and a history of measured values for each sensor are accessible through a web interface and are sent to a cloud service.
For this first step I acquired the following parts:
- Raspberry Pi 3 - installed and updated to latest Raspbian Jessie version. Being first time I installed Jessie, I had part of a few surprises especially on the networking side, my settings made on Wheezy did not work anymore. A little research was required to put everything back on track. Some work is still required on wireless and bluetooth part.
- ESP8266-201 - for first test purposes, I bought two ESP8266-201 modules. I choose this version, among many ESP8266 versions because this version have many GPIO pins accessible compared for example with ESP8266-01 modules. Besides, ESP8266-201 have both onboard and external antenna which might be required if nodes are spread around the home.
One downside, for me at least, these modules work on 3.3V and are quite power hungry, so I think the nodes will not be battery powered. I considered and Adafruit HUZZAH ESP8266 Wifi because have onboard voltage regulator and level shifting to 3.3V, but for now ESPs were easier to get.
- Voltage regulator - I use for now Pololu Adjustable Step-Up/Step-Down Voltage Regulator S7V8A set to 3.3V. I'll use a 3.3V fixed voltage regulator for next version.
- DS18B20 - 1-Wire digital thermometer - quite easy to use with ESP8266 thanks to existing libraries.
I built so far two of these wireless nodes, one on breadboard, one on perfboard, I plan to build at least two or three more nodes to cover all places I need. The code to send measurements to RPi is still work in progress, I'll post it as soon as it is usable along with the code on RPi side.
All the best
-=Seba=-