In this chapter, we saw how to use three sensors that can be used for obstacle avoidance and collision detection. The crash sensor is a digital sensor that can be used to tell when the sensor bumps into something. The infrared obstacle avoidance sensor is also a digital sensor that can tell when the sensor is within a certain distance of an obstacle. The Ultrasonic range finder is an analog sensor that can be used to tell how far an obstacle is from the sensor.
In the next chapter, we will look at some different types of LEDs and see how we can use them in our projects.