Tech Diary

In my previous blog post, I have written about the integration of Google Cloud IoTCore using UDOO and how the temperature information is sent up to Pub/Sub. In the post, I will describe the integration of Raspberry PI to Google Cloud IoTCore. The primary communication protocol between the sensors and the IoTHub is mosquitto MQTT. For this setup, I have a temperature sensor using ESP8266 flashed with ESP Easy firmware. The ESP and sensor are battery power which set to wake up every 60 minutes to take the measurement and transfer this to Raspberry Pi. The IOT bridge is written in Python which bridges the internal MQTT messages and Google Cloud IoTCore. The sensor is battery power using a 3rd party Nokia BL-5C (1020 mah) rechargeable battery. This can be cheaply purchased from many battery shops or online. I have used 2 versions of the Wemos Mini charging shield version (1.1and 1.2). The details on how to modify the version 1.1 to be able to read the voltage level of the ba...

Next, I need a Micro P rocessing Unit (MPU), Micro-controller (MCU) and the software. After some design considerations, I have decided the brain of my system shall be a Raspberry PI. Raspberry is easily available. I have purchased mine at Taobao for less than S$70. It comes with a casing, power supply, 3xheat sinks, fan and a 16GB micro SD. This is the cheapest I can find. There are so many documentations, videos and websites on Raspberry Pi.  I watched a youtube clip showing Google Home assistant can be easily installed on a Pi. That sealed my decision to choose Raspberry Pi.  The next piece shall be the automation software, Currently, the most popular Home Automation control software are Openhab and HomeAssistant. I do not have time to evaluate both and settled for Openhab as I am more of a Java programmer. In case anything that needs debugging, it will be easier for me (but it turned out that I do not really need to look at the code). I like the Arduino ...