BLINKING LED
01. Blinking LED
01. Blinking LED
The first example of digital output uses a LED to realize a blinking LED. It can be managed from the Internet via start and stop commands.
Figure 1 - LED circuit
Figure 1 - LED circuit
1. Circuit
1. Circuit
Connect the LED as shown in figure 1:
- positive PIN to the PIN d2
- negative PIN to the PIN GND (Ground).
The long PIN is positive as shown in Figure 2.
2. Sketch
2. Sketch
Write a sketch K to define:
- the output connection: led::d2
- the commands to control the LED: start, stop
led :: d2
start = [led=!led #1]
stop = [led=0]
or simply load the sketch with the command
] load e01_blink
Figure 2 - positive and negative PIN of a LED
Figure 2 - positive and negative PIN of a LED
3. Try and learn
3. Try and learn
Try the following commands now:
] ?
--- Pin connections
led :: d2
--- Commands
start = [led=!led#1]
stop = [led=0]
shows the loaded sketch
] start
the led starts blinking
] pause
the flashing of the led stops
] play
the flashing of the led resumes
] ??
--- Periodic commands
led=!led #1
shows the periodic commands running
] trace=1
ok
]
# led=!led
]
# led=!led
...
traces the commands running
] trace=0
ends the tracing
] stop
turns off the led and stops the flashing of the led
] ??
null
stop command also clears the commands running.
4. Summarizing
4. Summarizing
In this lesson you learned:
- how to use a LED
- the commands: load, ?, start, pause, play, ??, trace, stop.