Sunday, February 26, 2017

Week 7: Force Sensing Resistors and 7 Segment Displays

Number 1: Force Sensing Resistor
With no load on the force sensing resistor it had 0L resistance or just no connection for resistance for the multimeter then the we squeezed it the more resistance the multimeter read.

Load Resistance
No load 0L
Slightly Pinching 1.1 MOhms
Strongly Pinching 2 MOhms

Number 2: 7 Segment Display
Top led lights up when you ground pin 1
a.)
Video 1: 7 Segment Display explanation 

b.) Below are 2 photos showing the led display showing a 0 and 5. Its showing these by powering the display though the common voltage pin for all the leds and then grounding the cathode end with a resistor for the leds that we need lit up for the 0 or 5.
Display showing a 0
Display showing a 5

Number 3: Display Driver
a.)
Frist Input Combination
Table for First Input Combination.
Inputs High/Low Outputs High/Low
A 0 f 1
B 0 g 1
C 0 a 1
D 1 b 1
c 1
d 1
e 1


Second Input Combination


Table for Second Input Combination.
Inputs High/Low Outputs High/Low
A 0 f 1
B 1 g 1
C 1 a 0
D 0 b 0
c 1
d 1
e 1

We can say that the display driver using internal logic shown in this Truth Table to take the input numbers and output them into the right display for the binary number. as an example we had our 2 input combinations that we tried. The first combination had D high and A,B, and C low which would be binary 8. And to make that 8 it put on all  7 outputs to make the 8. Same with our second combination A and D low, B and C high making binary 6 It put on a certain 5 outputs to make the 6.

INPUTS        OUTPUTS                                                             
D C B A a b c d e f g
Low Low Low Low ON ON ON ON ON ON OFF
Low Low Low High OFF ON ON OFF OFF OFF OFF
Low Low High Low ON ON OFF ON ON OFF ON
Low Low High High ON ON ON ON OFF OFF ON
Low High Low Low OFF ON ON OFF OFF ON ON
Low High Low High ON OFF ON ON OFF ON ON
Low High High Low OFF OFF ON ON ON ON ON
Low High High High ON ON ON OFF OFF OFF OFF
High Low Low Low ON ON ON ON ON ON ON
High Low Low High ON ON ON OFF OFF ON ON
High Low High Low OFF OFF OFF ON ON OFF ON
High Low High High OFF OFF ON ON OFF OFF ON
High High Low Low OFF ON OFF OFF OFF ON ON
High High Low High ON OFF OFF ON OFF ON ON
High High High Low OFF OFF OFF ON ON ON ON
High High High High OFF OFF OFF OFF OFF OFF OFF

b.)
Video 2: Both Display Driver input combinations

Number 4: 555 Timer
a.)
555 Timer Hook up

555 Timer output on Oscilloscope
b.)
Theoretical: Frequency =  1.44/[(Ra + 2Rb)C] =  1.92 H
Duty Cycle = Rb/(Ra+ 2Rb) = 2/5
No, it does not. We are actually getting about half of the theoretical frequency.

c.)
Video 3: Force Sensing Resistor in series with Ra


Number 5: Binary Coded Decimal Counter
a.)
Video 4: BCD input and outputs measured via oscilloscope

Number 6: 7486 XOR gate
a.)
Video 5: XOR gate explanation

b.)
Video 6: XOR gate used in circuit
c.)

Number 7: Entire Circuit Connected Together


Circuit Block Diagram
Video 7: Entire circuit explanation


Number 8: Using AND and OR gates with LED


Video 8: Binary gate combinations


5 comments:

  1. In question 1 your values seem to be much higher than ours. For your table in question 3 it might be easier to read if you put 1 and 0 instead of high and low. Make sure you caption all of your pictures and videos, but other than that it is a good start.

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  3. good job guys but i think explaining the question will make it easier to understand how it was done, adding more explanation will always be helpful. Q7 and Q 3a is missing a lot of explanation. Also, in Q1 and Q3a your tables need captions . For Q1, the difference in of the values between our measurement and yours is huge, your result was in M ohms while our result was in K ohms and i think you had a problem with your force sensor because when you increase the force the resistance will decrease which is the opposite of what you got. it would be much easier to read the blog if the questions were included.

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  4. You guys did a really good job on the graphs this week. I feel like adding an explanation to your questions would help the public understand better what is actually going on in the blog. You have to add a few captions to your figures, and the high low table is kinda confusing to read. The videos are clear which puts you guys in track!

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  5. Best blog of the week and not full grade because you did not respond to comments.

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