Description: Test relay module: relay module VCC to 5V, GND to ground, IN to GND, the relay will jump, and when suspended, the relay will resume, so repeatedly, you can hear the relay "Kaka" sound. Tes soil moisture sensor module: fork probe and transmitter module with two wires. The transmitter module VCC is ted to 5V, GND is grounded. When the power is on, the light is always on, and the green (blue) light is flashing once. The fork probe is used. Directly inserted into the water, the green (blue) color indicator light is on. the red line of the water pump is ted to 5V, the black line is grounded, the pump works, pay attention to the test for 1 second, and it is not allowed to work in the air for a long time. Tips: 39; air for a long time. system, powere on the pump has been working, it is correct. Because in the air, the probe can not humidity, there is no problem if it is installed correctly in the pot. Specification: Color: as pictures shown Material: Plastic + Electronic components Cable length: Approx. 18cm / 7.09inch Battery box size: Approx. 6x7cm / 2.36x2.76inch Trasparent pipe length: Approx. 96cm / 37.8inch Package Includes: 1 Piece Relay module 1 Piece Soil moisture probe + comparison module 1 Piece Small Water Pump 1 Piece Battery box 1 Piece USB Power Cable