Make: Sensors

Chapter 10. Electricity and Magnetism

Can you feel the power radiate through your body? Of course not, even though electromagnetic radiation from power lines and cell phones is all around you. Electricity powers all your gadgets, especially the ones you build from this book.

Hall sensors detect a magnetic field. They come in different varieties: some just detect the presence of a magnet, while others can tell you the strength of the magnetic field in teslas.

Voltage and current sensors work like a multimeter, measuring electricity passing through them. They can easily measure power that would otherwise break a microcontroller’s analog input pin.

An electronic compass can tell you where magnetic north is. Better ones combine an accelerometer, so that ...