28029 Parallax Inc, 28029 Datasheet - Page 70

• Manufacturer Part Number: 28029
• Description: KIT PARTS SMART SENSORS W/TEXT
• Manufacturer: Parallax Inc

Specifications of 28029

• Accessory Type: Parts Kit
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: BASIC Stamp® or Javelin Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant
• Other names: 28029PAR

Page 58 · Smart Sensors and Applications
inDistance
time
PAUSE 200
SEROUT 14, 84, [22, 12]
PAUSE 5
DEBUG CLS, "Program running..."
DO
LOOP
Your Turn - Customizing the Display
ACTIVITY #5: TEMPERATURE'S EFFECT ON THE SPEED OF SOUND
This activity investigates changes in the speed of sound caused by changes in air
temperature. These changes in the speed of sound can result in visible changes to your
distance measurements.
Speed of Sound Vs Temperature and Percent Error Measurements
The speed of sound changes with air temperature, humidity, and even air quality. Neither
humidity nor air quality make enough of a difference to figure into Ping))) sensor
PULSOUT 15, 5
PULSIN 15, 1, time
cmDistance = cmConstant ** time
inDistance = inConstant ** time
SEROUT 14, 84, [128, DEC3 cmDistance, " cm"]
SEROUT 14, 84, [148, DEC3 inDistance, " in"]
PAUSE 100
√
√
√
The measurements are currently left-justified. Try centering them.
Try right justifying the measurements and displaying "Distance: " before the cm
measurement on the LCD's top line.
Modify the program so that it displays both of the distance measurements on the
top line. Then, display the actual echo time on the bottom line. You can display
it in millionths of a second (µs) by multiplying the time variable by 2 before
displaying it. Make sure your program waits until after it has done its distance
conversions before multiplying time by 2.
VAR
VAR
Word
Word