But once the coherer becomes conductive, the relay becomes energized and closes its switch. That switch activates the circuit that consists of the two solenoids F, the solenoid E and a battery ...

The setup uses a Raspberry Pi at its core and a set of ... They used common household solenoid valves because they are easy to control by relay, but unfortunately they are on/off only, so variable ...

can be connected together to form a circuit. A circuit diagram shows how the components are connected. The following symbols show the different components that can be found in an electrical circuit.

Roula Khalaf, Editor of the FT, selects her favourite stories in this weekly newsletter. Raspberry Pi is a quirky enterprise. Started by a foundation to make cheap microcomputers for schools ...