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esphome
ESPHome is a system to control your ESP8266/ESP32 by simple yet powerful configuration files and control them remotely through Home Automation systems.
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InfluxDB
Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.
A lot of people are jumping on you in the comments but not many are mentioning that, a better alternative than wiring sensors directly to Raspberry Pis is to use ESPHome - with this you can wire the sensors to extremely cheap ($10 or so) ESP32 microcontrollers, and have a single larger computer running Home Assistant.
NOTE:
The number of mentions on this list indicates mentions on common posts plus user suggested alternatives.
Hence, a higher number means a more popular project.