This is the HC-SR04 ultrasonic distance sensor. This economical sensor provides 2cm to 400cm of non-contact measurement functionality with a ranging accuracy that can reach up to 3mm. Each HC-SR04 module includes an ultrasonic transmitter, a receiver and a control circuit.
These simple switches are the Mechanical Bumper sensor for the SparkFun RedBot, giving you the ability to detect a collision before it really happens. This sensor works by acting as a SPST switch. When the "whisker" bumps into a foreign object it will make contact with a nut next to it, closing the connection and, by default, turning off the motor. By attaching these mechanical bumpers to you robot the whisker will bump something before your robot crashes into it.
The SparkFun Proximity Sensor Breakout is a simple IR presence and ambient light sensor utilizing the VCNL4040. This type of sensor is often seen in automatic towel and soap dispensers or automatic faucets. With the ability to detect objects qualitatively up to 20cm away, you will be able to detect if something is there and if it is closer or further away since the last reading. Utilizing our handy Qwiic system, no soldering is required to connect it to the rest of your system. However, we still have broken out 0.1"-spaced pins in case you prefer to use a breadboard.
Infrared proximity sensor made by Sharp. Part # GP2Y0A21YK has an analog output that varies from 3.1V at 10cm to 0.4V at 80cm. The sensor has a Japanese Solderless Terminal (JST) Connector. We recommend purchasing the related pigtail below or soldering wires directly to the back of the module.