If you are searching an ultrasonic ranging module, the HC-SR04 is good choice: Its stable performance and high ranging accuracy make it a popular module in electronic market. It's cheaper than an IR range finder with similar range accurancy and distance.
Ultrasonic is an ultrasonic distance measuring sensor unit, with the capability of simultaneous reception and transmission. The ultrasonic probe has a sound frequency of 40KHz, a direction angle of ±20 ° and an accuracy of 1mm. The internal part is calculated by an RCWL-9600 ultrasonic distance measuring chip, and the measurement results can...
The 80cm Infrared Proximity Sensor is a General Purpose Type Distance Measuring Sensors, this sensor takes a continuous distance reading and returns a corresponding analog voltage with a range of 10cm (4") to 80cm (30"). Can be used in TVs,personal computers ,cars and so on.