This chapter gave us lot of knowledge about the RasPi and ultrasonic sensor interfacing, and we enjoyed a lot while building the project. You got to understand how ultrasonic sensors work. You understood that the voltage levels must be the same between the RasPi and the sensors. We used a voltage divider to convert 5V to 3.3V for the RasPi. We set up the hardware and software to start executing the project. We got the distance measurement of any target devices in our lab. At least now, we know how far our ceiling is!

We thought to make a project for a good cause, and we created wearable devices using the RasPi and a USB battery pack. Playing a sound on RasPi device to indicate the alerts was a real fun. It was then interesting to know about crontab to start the file execution at the boot-up of the RasPi module without any need of configuration.

In the next chapter, we will play with the temperature-humidity sensor along with the light sensor. The RasPi does not have any analog-to-digital...