M5StackSolar2MQTT

measure solar panel voltage and current on M5Stack, transmit via MQTT to Node Red

Hardware / BOM

• Solar Panel with Controller (and USB output) - output current must not exceed 4A
• M5Stack
• Voltmeter Unit (ADS1115)
• Ammeter Unit (ADS1115)
• Grove-T Connector
• Grove Cable

High-Level flow

• Solar panel
  • Ammeter wired in line between solar panel and controller
  • Voltmeter wired in parallel to the solar panel
• Solar Controller
  • M5Stack plugged into USB output of solar controller
• M5Stack
  • connect to Wifi & MQTT
  • measure voltage and current every couple of seconds and display on screen
  • transmit via MQTT every 20 seconds as a JSON object on topic "SolarPanel"
• Node-Red
  • receive and parse the JSON object on topic "SolarPanel"
  • calculate power and convert units
  • upload resulting data to InfluxDB
• Grafana
  • load data from InfluxDB and display it

Installation

• Install and configure
  • Node-Red plus this node:
    • node-red-contrib-influxdb
  • InfluxDB
  • Grafana
  • I used DietPi to conveniently install all on a Raspberry Pi
• Create a database in InfluxDB
• Import M5Stack project to UIFlow, adjust your MQTT details and upload to M5Stack
• Import Flow to Node-Red, configure MQTT and InfluxDB details and deploy
• Import Panel to Grafana and configure InfluxDB details

Images