Datasheet

Chapter 2: EEPROM Tricks and Program Tips · Page 59
Building and Testing the LED and Piezospeaker Circuits
The LED and piezospeaker circuit shown in Figure 2-4 is an interesting combination of
the individual circuits. Instead of connecting the LED and piezospeaker to separate I/O
pins, both circuits are connected to the same I/O pin. This circuit can come in handy,
especially if you are running low on available I/O pins. Keep in mind that this circuit
will always light the LED when the speaker plays a tone. Likewise, if the LED is turned
on/off, the speaker will make a clicking sound. The clicking sound when the LED
changes state can actually be useful for "hearing" what's going on with the status
indicator LED during debugging sessions.
√ Remove all existing circuits from the SumoBot's white breadboard space.
√ Build the LED circuit shown in Figure 2-4 on the SumoBot's breadboard.
Parts List
(2) Jumper wires
(1) LED - red
(1) Resistor - 470 Ω (yellow-violet-brown)
(1) Piezospeaker
Figure 2-4 Parallel LED and Piezospeaker Circuits
This circuit should be tested to make sure your programs can make the LED turn on/off
as well as make the piezospeaker chime a few notes. In the next example program, you
will see this
PIN directive: