SRF04 ultrasonic distance sensor provides non-contact distance sensing function in the range of 3cm ~ 400cm with accuracy up to 0.3mm. This module has a stable performance, high distance measurement accuracy, and compact-size, and it’s simple and...

Infrared roadblock sensor.  Red: 4.5V to 5V, please add a resistor of 1K ohm to limit the current.  Yellow: TTL output to MCU, please add a pull-up resistor. Black: Ground. Sensing Distance: 3-80CM

This is a bump detector that can detect a crash event.