loadingDigital Electronics &Chip Design Lab Manual III:Martian Identification Device? 1999 David HarrisAs you may have read in the latest issue of the National Enquirer, NASA is about tolaunch its first manned mission to Mars! You have been commissioned to accompany themission as the electronics specialist.
Part I: Political Incorrectness
Soon after liftoff, Mission Control radios the crew and informs you that there is a smallmodification that needs to be made to the life support circuitry in order to properly recycleyour air. As it is a simple change, Martin Fodder, the first politician in space, offers tomake the change for you and scurries off to the lab.
Hours pass and you begin to notice stuffiness and an acrid tinge to the air. Wanderingdown to the lab, you encounter Martin leaning over a smoking chip. A tangle ofblackened wires on another table and the smell of ozone indicate that Martin has beenhaving difficulty. As you watch from the hatch, Martin begins chanting over the mess:
By blood of gerrymander,And barrel of pork,With guano of bat,Let this circuit work.
You interrupt the poor fellow and ask him what is going wrong. He responds that he hasdeveloped a circuit that should solve the problem, but that it is so complicated that he ishaving trouble building it. He hands you the following circuit, sketched on the back of atraffic ticket:
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ABF
The circuit he designed is obviously quite a bit more complex than necessary. Help Martinby constructing a truth table for F in the space below. Then design a new circuit that willimplement the function using as few gates as possible.
A0011
Draw new circuit here:
B0101
F
When you complete this section, have it checked off.
Part II: A Taxonomy of Native Martian Fauna
After fixing the air recycling circuitry, you finally take a deep breath of fresh air. There isa boring period of many weeks eating nothing but dehydrated astronaut food and slopsqueezed from toothpaste tubes, but finally you reach Mars and land the spacecraft.To the surprise of everyone save a few science fiction writers, your mission crewdiscovers that Mars is crawling with a wide form of life never detected by previousunmanned missions (see attached photograph of barren landscape taken by the Vikinglander). Being good scientists, the crew immediately begins to classify the various speciesof alien life.
The biologist on board develops a set of tests to classify Martian life forms. The testscheck if the species is green (using advanced spectroscopy equipment), if it gets around ina flying saucer (using radar detectors), if it is carnivorous (by sticking Martin Fodder’sarm in its mouth and observing if it bites), and if it has hair (by looking for thecharacteristic barber shop).
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YesNoYes
YesNoYes
No
NoYesNo
Your job is to build a circuit that takes the results of these four tests (Green, Saucer,Carnivore, and Hair as Boolean variables with 1 = Yes and 0 = No) and lights up one offive LEDs corresponding to Atman, Blemp, Craph, Drydum, or Unknown.
Your first task is to write a Boolean equation for each species. Craph has been donealready for you.A =B =
C = GSHD =U =
Have your equations checked off. It’s important to thoroughly understand the problem sofar so that you can build a functional circuit.
The next step is to actually design a circuit that solves this classification problem. Youshould be able to do it using gates on the chips in your kit. Draw the circuit below. Itshould take inputs from four switches (Green, Saucer, Carnivore, and Hair) and control 5LED outputs (Atman, Blemp, Craph, Drydum, and Unknown). Have your circuit checkedoff, then build the circuit on your protoboard.
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When your circuit works, congratulations! Come back next week for the next excitinginstallment of Digital Electronics & Chip Design!