This sensor is pretty simple! Instead of headers, we have a 4-pin JST PH connector. This makes it easy to plug in a cable that goes to another board or prototyping kit.

Looking at the image above, from top to bottom, the pinout is

• GND - power and logic ground
• VIN - 3-5V DC (use the same power voltage as you would for I2C logic)
• I2C SDA - there's a 10K pullup to VIN
• I2C SCL - there's a 10K pullup to VIN

We suggest these cables, they're even color coded!

To connect this STEMMA I2C device to STEMMA QT controllers, you can use the cable below.

On the back there are 3 SWD programming dots (see the schematic for the exact pinout in case you want to reprogram the chip).

I2C Addressing (using multiple sensors)

There's also two I2C address jumpers. You can have four different I2C addresses to use one microcontroller with four soil sensors. You can use 4 channel or even 8 channel multiplexers to have even more sensors on one microcontroller.

The default address is 0x36, but you can select between 0x36 and 0x39 inclusive by shorting AD0 (to add 1 to the address) and/or AD1 (to add 2 to the address)