Capacitive I2C soil moisture sensor (โมดูลวัดความชื้นในดิน)

The sensor can be read via I2C protocol and provides these features:

• Soil moisture อsensing
• Light sensing
• Reset chip
• I2C address change
• Deep sleep

This is the second version of my sensor with some improvements:

• 16MHz crystal for better repeatability and better Raspberry Pi support
• Thermistor for accurate temperature measurements
• Increased moisture reading resolution (almost double!)
• Holes to fasten a cable with a zip-tie

Technical data

• Version 2.7.5
• Supply voltage 3.3V - 5V
• Current consumption: 1.1mA @ 5V, 0.7mA @ 3.3V when idle, 14mA @ 5V, 7.8mA @ 3.3V when taking a measurement. When constantly polling sensor at full speed, current consumption averages to 4.5mA @ 5V, 2.8mA @ 3.3V
• Operating temperature 0°C - 85°C
• Moisture reading drift with temperature - <10% over full temp range
• Don't forget to provide pullups for SCL and SDA lines
• Default I2C address is 0x20 (hex)
• To read soil moisture, read 2 bytes from register 0
• To read light level, start measurement by writing 3 to the device I2C address, wait for 3 seconds, read 2 bytes from register 4
• To read temperature, read 2 bytes from register 5
• To change the I2C address of the sensor, write a new address (one byte [1..127]) to register 1; the new address will take effect after reset
• To reset the sensor, write 6 to the device I2C address.
• Do not hotplug the sensor into the active I2C bus - address change command has no protection and this might result in a random number set as an address of the sensor. Use I2C scan sketch to find out the address if the sensor stops responding with proper valu