Sensors - BeagleBone - page 115

Solution
To make this recipe, you will need:
▪ Breadboard and jumper wires (see “Prototyping Equipment” )
▪ LV-MaxSonar-EZ1 Sonar Range Finder (see “Miscellaneous” )
All you have to do is wire the EZ1 to one of the Bone's analog-in pins, as shown in Fig-
ure 2-11 . The device outputs ~6.4 mV/in when powered from 3.3 V.
WARNING
Make sure not to apply more than 1.8 V to the Bone's analog-in pins, or you will likely dam-
age them. In practice, this circuit should follow that rule.
Figure 2-11. Wiring the LV-MaxSonar-EZ1 Sonar Range Finder to the P9_33 analog-in port
Example 2-6 shows the code that reads the sensor at a fixed interval.
Example 2-6. Reading an analog voltage (ultrasonicRange.js)
#!/usr/bin/env node
var b = require ( 'bonescript' );
var ms = 250 ; // Time in milliseconds
setInterval ( readRange , ms );