Aart MQTT notes

These are my personal notes & developments; any opinion expressed on this page is just that :-)

MQTT on Wifi Principals

• assume no privacy
• Use short, systematic but human readable topics and messages. Using a room number in common use is fine, an eight byte digital address is not. Use standard units and formatting (e.g. aart/kitchen/temperature 17,2 )
• Minimize the amount of wires, use more nodes if required
• Hardware- and MQTT configurations are managed in the source for now, as nodes tend to be all different. Counter offsets can be set after a power up by posting on MQTT.

ESP8266 Node firmware development

ESP Boards

• Wemos D1 mini

Sensors

Use test programs to test sensors and hardware / Wifi / MQTT setup before putting it together.

• OneWire Temperature lib / example:
• Neopixel lib / example:
• HIH6030 (i2c temperature & humidity):
• Senseair K30 analog (CO2):
• Thermal mains voltage sensor:
• Adafruit MQTT example:

Pi3B Broker

Makerspace Leiden workshop on 27-02-2017

Raspbian

• Download: Raspbian lite
• Install on SD card following the instructions

Using a serial console

• add line "enable_uart=1" at the end of /boot/config.txt
• Pins: GPIO 6 gnd, 8 Pi Txd, 10 Pi RxD - 3V3 logic levels (!)
• Speed: 115200

Update

Run:

• apt update
• apt -y upgrade

Configure WLAN as accespoint & build a bridge

hostapd