Page 144 - The Definitive Guide to Building Java Robots

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CHAPTER 4 ■ SENSORS 125

Figure 4-13. The Sharp IR Sensor GP2D15

Now that you’ve seen some of the sensor types (that return only logical values), I’ll describe
a BASIC Stamp program that returns single or multiple logic sensor readings, and also explain
the Java class that reads it.

Code Objective

The code objective here is to return single or multiple logic readings from the microcontroller,
indicating a true or false.

Code Discussion
In the first example, I’ll create the BASIC Stamp program (see Example 4-4). For the single
switch, I’ll either return a “0” for false or a “1” for true. For reading multiple switches at once, it
will return a string of ones and zeroes as soon as the readings are made—thus, when reading
from multiple switches, the example output from the BASIC Stamp might be “010” or “111,”
these would then correspond to “false, true, false” and “true, true, true,” respectively.

Example 4-4. switch.bs2

'{$STAMP BS2}
' {$PBASIC 2.5}
'{$PORT COM1}

cmd VAR Byte
N9600 CON 16468
switch1 CON 1
m_switch1 CON 2
m_switch2 CON 3
m_switch3 CON 4