28128 Parallax Inc, 28128 Datasheet - Page 163

• Manufacturer Part Number: 28128
• Description: KIT BASIC ANALOG/DIGI PARTS ONLY
• Manufacturer: Parallax Inc

Specifications of 28128

• Accessory Type: ADC, DAC
• Product: Microcontroller Accessories
• For Use With/related Products: BASIC Stamp® 2 and Board of Education
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Questions
Challenge!
1. Given the circuit in Figure 8.3, how long will it take to discharge if the value of
2. For the discharge time in Question 1, would you expect any of the variables in
3. If the light conditions are so low that none of the capacitors in the kit work any
4. For better resolution in the higher end of the light level scale, you can also
1. Design a circuit which has two photoresistors that are monitored. Assume that
2. Program the BASIC Stamp to monitor the light level at both of the photoresistors
3. Try holding different colored papers in front of the photoresistors; black and
4. Make sure your program from Challenge #3 is not affected by the ambient light
the photoresistor is 47 k ?
Program Listing 8.1 to overflow? If so, which ones? Explain your answer.
more, a store bought capacitor might be the answer. What values of capacitor
might you try to find? Explain your answer.
reduce the value of a in Program 8.1. How would that affect your Debug
Terminal readout and the sound of the piezoelectric speaker?
you will be displaying the light intensity information on the Debug Terminal,
and that you won't be using a piezoelectric speaker.
and display the information using the Debug Terminal.
white will work best. Write a program to distinguish which photoresistor senses
white and which sees black.
level in the room. Hint: You will need to compare the RELATIVE intensities of
the light measured by both photoresistors instead of comparing them to some
fixed number that was experimentally determined using a fixed value of ambient
light.