You can simulate a switch by connecting and then disconnecting one of the battery leads from one of the LED leads. Switches in circuit diagrams are often represented ... and LED, try one of the ideas ...

Before the software part, let's first set up the circuit to connect the LED to the Arduino. The completed circuit should look like Figure 2. Figure 2. Circuit for a Single LED Blink Next, in your ...

His test circuit uses six 2N2222 transistors to protect the Arduino from excessive current. You can see six red LEDs above which are inline with the base of teach transistor.

Then he holds up a baseball cap with LEDs stitched into the fabric. Most didn’t realize their instructor, a rising star in the DIY-electronics movement, is also a 12-year-old. “This is a Gas Cap.