Hoang Lihuo

Working of Sensor The soil moisture sensor consists of two probes which are used to measure the volumetric content of water. The two probes allow the current to pass through the soil and then it gets the resistance value to measure the moisture value. When there is more water, the soil will conduct more electricity which means that there will be less resistance. Therefore, the moisture level will be higher. Dry soil conducts electricity poorly, so when there will be less water, then the soil will conduct less electricity which means that there will be more resistance. Therefore, the moisture level will be lower. This sensor can be connected in two modes; Analog mode and digital mode. First, we will connect it in Analog mode and then we will use it in Digital mode. Specifications The specifications of the soil moisture sensor FC-28 are as follows: Input Voltage 3.3 – 5V Output Voltage 0 – 4.2V Input Current 35mA Output Signal Both Analog and Digital Pin Out...

Infrared obstacle avoidance sensors This Infrared Obstacle Avoidance Sensor returns a signal when it detects an object in range. The range of the sensor is around 2-40 cm is distance. It operates at 3.5 to 5 volts at around 20 milliamps. The Obstacle Avoidance Sensors usually come in two types - with 3 and 4 pins. The 3 pin version does not have the ability to be enabled/disabled. The 4 pin version has optional Enable pin. Infrared obstacle avoidance sensor is designed to detect obstacles or the difference in reflective services. One application is to help a wheeled robot avoid obstacles with a sensor to react to adjustable distance settings. This device has an infrared transmitter and receiver, that forms the sensor pair. The transmitter LED emits a certain frequency of infrared, which the receiver LED will detect. The receiving LED will detect some of the signal back and will trigger the digital on/off “signal” pin when a specific threshold “distance” has been detected. Most b...