Test the relay module: connect the relay module VCC to 5V, GND to ground, IN to GND, the relay jumps, and when IN is suspended, the relay recovers, so you can hear the relay "" sound repeatedly. Test the soil moisture sensor module: connect the fork probe and transmitter module with two lines, the transmitter module VCC is connected to 5V, GND is grounded, just after power-on, the red power light is always on, green (blue) color indication The lamp flashes faintly once; the fork probe is directly inserted into the water, and the green (blue) light is on. Connect the of the pump 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. Through adjusting the potentiometer to control the soil humidity threshold,can automatic watering the vegetable garden, garden, control the flower pot soil moisture. Easy assemble, make your life more automated, particularly suitable for people who travel frequently! Do not pour water directly on the sensor. The humidity of the water rust the sensor. Note: This can be free of welding, but you need to peel the wire, twist the copper wire together, and protect it with black tape. The pump cannot be operated in the air for a long time. The system is connected, power on, the pump has been working, it is correct, because in the air, the probe can not detect the humidity, so the pump has been working, there is no problem in the correct installation into the pot. Note that water should not be poured directly on the probe. Many people don't know that the humidity of the water be rusted and destroyed soon. This does not provide power, you can use the charging treasure (5V DC) as the power supply, or use 4 5th battery box and load 4 batteries. Colour: black Material: plastic Package Contents: 1 * Relay module 1 * Mini water pump 1 * Battery Storage Case Holder 1 * USB power cable 10 * Jumper wires 1 * 0.5m Vinyl Tubing 1 * Soil Moisture Detector Module Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.