APPLY YOUR BREADBOARD KNOWLEDGE
A simple exercise will help you to put into practice the principles you’ve learned in this article. The word simple is an understatement but, as they say, from tiny acorns mighty oaks grow.
First, build the circuit that’s shown on the left of the diagram (using a red, yellow or green LED because blue or white ones will need a different value of resistor), but without making the connection represented by the red line. Although lines on circuit diagrams would normally appear black, we’ve coloured them in the same colours as the corresponding patch leads that appear in the diagram on the right, which is a portion of a breadboard.
Because the connection relating to the gold line is made via an internal connection in the breadboard, only connect the red lead between holes on the breadboard, and the red and blue leads from the breadboard to the SBC, which is only acting as a power supply. Having done this, the LED won’t illuminate, because one end of the resistor is unconnected. To see it light, use the other red patch lead to complete the connection of the resistor to +ve.
Now, to use the SBC to control the LED, disconnect the upper end of red lead that runs from the resistor to the +ve row of the breadboard, and connect it instead to a pin on the SBC’s GPIO that can be used as a digital output. Finally, write a simple bit of code to flip that digital output between 0 and 1 every second to see the LED flash on and off.