So far, in all the previous chapters, we have been building and powering the prototypes by plugging in the Arduino board into the computer using a USB cable. First, the Arduino board would get powered by this USB connection. In turn, the Arduino board was supplying power to the connected peripheral devices.

While building real-world device prototypes, independent (not from a computer's USB port) power sources must be used, so that the device prototype can work without being connected to a computer. Hence, in this chapter, we will learn how to make standalone devices that have their independent power sources.

You will learn the following topics in this chapter:

• Introduction to standalone devices
• Different considerations for power sources based on the type of project
• Building a distance measurement gadget
• Using an LCD panel
• Using battery power
• Using HC-SR05 ultrasonic sensor