A rather special looking pool sensor measuring the pool temperature and transmitting it via WiFi to Blynk App and to a MQTT broker https://www.instructables.com/id/Crocodile-Solar-Pool-Sensor/
Version 1.0
- Fully independent from power sources (solar panel feeds the LiPo battery)
- Low power ESP8266 WiFi connected sensor
- Rather high precision temperature sensor (DS 18b20)
- Data transmission of temp and voltage to Blynk APP for your mobile phone
- Data transmission of temp and voltage to a MQTT broker (can be switched on/off in Settings.h)
Version 1.1
- Corrected error handling if there is no WiFi
Version 1.2
- added switch to change between Celsius and Fahrenheit (Settings.h --> is_metric true or false)
Version 1.3
- added NTP time fetch, DST conversion and data transmission of last update timestamp to Blynk APP
Version 1.4
- added battery saving mode when batt level goes below 3.3 V
Please see also how to display the data on a LED matrix:
https://github.com/3KUdelta/MDparola_MQTT_monitor