This digital input example uses a Button to turn on and off a led.
Figure 1 - button circuit
Connect the Button and the led as shown in Figure 1:
- led positive PIN to d7
- led negative PIN to d8
- Button to PINs D3 and GND.
The longer LED PIN is the positive.
Button PINs can also be inverted.
Write a sketch K to define:
- the output connections: led :: d7, gnd :: d8
- the input connections: Button :: !D3
- the command to initialize the system: start
Button :: !D3
gnd :: d8
led :: d7
start = [gnd=0,led=Button *]
or simply load the sketch in the workspace with the command
] load e05_button
3. Try and learn
Initialize the system with the command:
the LED is off.
If you press the button the LED lights up and if it is released the LED goes out.
In this lesson you learned or repeated:
- how to use a Button
- the command: start.