### Weather Station with Light, Humidity, Temperature: More Data QA/QC

#### Materials

The cost of those sensors are cheap, below $2 for each sensor. Items a bit more expensive are ESP8266 and 18650 Lithium battery. Here are the full list of materials as a reference: 1. 2x Light Dependent Resistors with 2x1kΩ (pull down) 2. 2x TSL2561 Luminosity Sensors 3. 1x BH1750 Luminosity Sensor 4. 1x TEMT6000 Light Sensor 5. 2x DS18B20 Temperature Sensors 6. 1x DHT21 Humidity and Temperature Sensors 7. 1x Si7021 Humidity and Temperature Sensors 8. 2x LEDs (Read & Blue) with 2x ~220Ω 9. 1x I2C ADS1115 16-bit Analog-to-Digital Converter (ADC), ~$1.6
10. 1x TP5400 5V Boost-up Lithium Charger, $1.32+ a piece 11. 1x ESP8266 WeMos brand, ~$3
12. 1x 18650 Lithium Battery, roughly $5 a piece 13. 1x Push-lock Switch 14. PCB Dev Board, wires, soldering wire, multimeter 15. Plastic box (I used a box used for convenient foods) 16. Ready to spend your next week for the whole process The cost of parts is about$25. After soldering this is how my weather station look like:

Notes:

• I attempted incorporating two TMP36 Temperature Sensors but the reading was off a few degrees. Maintaining a precise 3.3V is the key.
• I did not know I2C multiplexer - I2C expander when starting the circuit. That limits the number of Si7021 or HTU21 Humidity and Temperature sensors. They are using x40 (60) I2C address and no reconfiguration available.