Datasheet

Chapter 3: EEPROM Tricks and Program Tips · Page 141
11. What factors should you keep in mind when selecting a frequency for a given
SumoBot ring?
12. What label designates the header with the front-left QTI sensor?
13. What connections does the SumoBot board make to the header with the front-left
QTI Sensor that you don't have to build on a breadboard?
14. How does the BASIC Stamp turn the power to a QTI on and off?
15. How many components are on the QTI sensor?
16. What water analogy was used for the infrared transistor inside the QRD1114?
17. Does the QRD1114 need a 38.5 kHz infrared signal?
18. Regarding Figure 3-11 on page 99, why does V
0
decay more quickly when the
infrared transistor receives more IR?
19. Regarding Figure 3-11 on page 99, what does each of the three downward curves
indicate?
20. How does voltage decay relate to the amount of infrared a surface reflects? Use
black and white as examples.
21. What are the measurement units of
RCTIME and PULSOUT in the BASIC Stamp
2?
22. What code block can you use to improve the accuracy of the pulse-decay trick?
23. With the pulse-decay trick, are the QTIs active-high or active low?
24. How do the circuits from the side-mounted IR object detectors differ from the
front-mounted ones?
25. How much more memory does it take to use a sensors variable to store all the
individual sensor bits?
Exercises
1. Write a routine that counts the number of IR interferences detected in a minute.
2. Write a routine that tests the IR receiver's frequency response at increments of
250 instead of 500.
3. Calculate the value threshold will store in QtiSelfCalibrate.bs2 if the white
measurement is 100 and the black measurement is 2000.
4. Expand the band of frequencies examined by TestFrequencyResponse.bs2 from
36 kHz ≤ f ≤ 42 kHz to 33 kHz ≤ f ≤ 45 kHz
5. Modify TestFrontQtiLineSensors.bs2 so that it notifies you if tilt is detected.
6. Calculate the time it would take 3 QTIs to each take measurements that average
RCTIME measurements of 2500.
7. Modify the Your Turn program from Activity #7 so that it displays a 1 in
sensors.BIT7 if all IR detectors simultaneously detect an object.