Teensy-based weather badge that logs humidity and temperature to Adafruit.io via WiFi:

Teensy WiFi Weather Logger

Bill of Materials

• Teensy 3.2, OSH Park Edition
• ESP-01 (ESP8266 SoC)
• Adafruit I2C OLED (128×32)
• Adafruit I2C BME280 (temp/hum/press)
• 10K Ohm through-hole resistor

The Kicad design files and Arduino source code are hosted on GitHub:

teensy-wifi-weather-logger

The sensor data is logged to Adafruit.io via ESP8266’s WiFi connection:

Adafruit.io Dashboard

Adafruit.io feeds

• temperature-celsius

• temperature-farenheit

• humidity

Video of establishing WiFi connection and logging weather data: