Some environmental data coming from tests in my apartment, located in Castelplanio, Le Marche, Italy.
ESP8266 running NodeMCU with a DHT11 to report humidity and a BMP180 to report pressure and temperature. The Sensor also reports battery voltage which is 2xAA batteries. Photo: http://imgur.com/hDpeNxj
Freezer-to-Frigidaire, ESP8266 powered freezer cell periodically shut down to stay within typical refrigerator temperature range (e.g. 2 to 5°C) A DHT22 inside the freezer is polled and a 5V relay and a cascaded BIG 220v SSR are switched accordingly.
PulseSensor connected to Arduino Nano along with algorithm code to read pulses from sensor then formulate BPM and send BPM values to NodeMCU ever Minute. and the nodeMCU with Lua firmware waits for BMP data, once received it updates BPM values to ThingSp