If you’ve ever used the ‘analog’ joystick on PS2 (PlayStation 2), you’ll find this Grove Thumb Joystick easy to pick up. As you’d expect, it works with all Grove products and features two direction movements which give out different analog signals (they’re actually two potentiometers). The resistor is ~10k for each.
The joystick features a push button for special applications, and in working mode it outputs two analog values which represent two directions. Compared to a normal joystick with a range of about 1023 when the button is pushed, the value of this device is restricted to a smaller range (such as 200~700) to let the MCU identify the pressing action. As ever, step by step PDF guides are available from Grove to get you up and running quickly.