UCR CS122B, Winter 2003, Homework 2: eBlocks

Due Tuesday, Jan 21, 2003, at 10:00 a.m. Turn in a single Word document, named ucr_cs122b_win03_hk2_yourfirstname_yourlastname.doc, electronically via the turnin page.

Below are listed several eBlock Challenges. For each system description see if you can build it using the eBlocks provided .

Don’t work or discuss with each other. Normally we encourage group work but in this case we want to see how individuals use eBlocks and how they solve the problems we pose. As you work through the problems take note of how long it takes to find a solution, what aspects were unclear, where did you encounter problems, and what eBlocks did you want to use but were not available to you. You will be asked to discuss these issues in a later question.

There are several assumptions you can make. First, each eBlock contains it’s own power supply - batteries, and we assume that these batteries will last for years. Power consumption is not something you should worry about. Second, the wireless transmitter has a range of 1,000 feet. In most situations the signal sent by the transmitter should have no problem reaching the receiver. You can also assume anything sent by the transmitter will end up at the receiver correctly; you don’t need to worry about error checking.

Please make sure that your diagrams and responses are clear and legible.

  1. Person in Backyard
    You want to detect if there is activity (or motion) in the backyard. If there is any activity, alert the homeowner by turning the led from green to red.

  2. Temperature Alert
    You have a computer server room. If the temperature in the server room goes over 80 degrees, your servers will die. Construct a system that monitors the server room to see if the temperature is above 80 degrees, if this temperature is reached or exceeded alert the system administrator by sounding a buzzer.

  3. Blinking LED
    Imagine you want to throw a party and you want to add excitement. A disco ball or some sort of lights would be nice but who wants to spend all that money for flashing lights. Instead can we build a system that flashes a light, the light turns on for 10 seconds then turn the light off for 10 seconds.

  4. Entry Light
    You want to illuminate the front porch area. This area should be lighted when it is both dark and someone is in the porch area, or during the hours of 7pm-10pm.

  5. Mail Indicator
    Suppose you have a fancy mailbox, like the one shown below, that does not have a flag. Build a mail indicator system that indicates to the homeowner when new mail arrives.

  6. Build your own system
    Be creative, what kind of system would you build with eBlocks? Try to use the eBlocks provided. However, if you think you really need an eBlock that’s not included go ahead and incorporate your own.

  7. Feedback
    Answer each of the questions below. Please respond thoroughly, but be concise (i.e. don’t just respond yes/no). The entire answer to this problem should probably be 1/2 to 1 page long.
    • Were any of the eBlock descriptions and interfaces confusing? Which ones? How can they be clarified?

    • Was it difficult to compose systems with the eBlocks? Which aspects were difficult? How can it be improved?

    • Do you think the set of eBlocks provided can be used to cover a wide range of systems? If not, what other eBlocks are needed?

    • Do you think that the eBlocks can be used to build useful systems or are they just a toy to play with? Explain.

    • eBlocks are targeted for the general public. Do you think that an ordinary person can pickup an eBlock set and build systems quickly and easily? If not, what further help would an ordinary person need?

    • If we produced eBlocks would you buy a set? If no, why not? If yes, what would you do with it?

    • Other comments/ideas/suggestions.