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2

Quiz Preparation

Have Quiz sheet ready. Title = QUIZ 6»Name (L, F, MI), »Today’s date 9/25/12, »Lab day , time» section number

Lab Day/Time Section Number

Monday, 1:00 8

Monday, 3:00 9

Wed., 1:00 10

Wed, 3:00 11

Friday, 1:00 12

Lab Day/Time Section Number

Mon. 1:00 8

Mon. 3:00 9

Tue. 2:00 36

Wed. 1:00 10Wed. 3:00 11Thu. 2:00 35Fri. 1:00 12

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Announcements First professional development memo

(PDM) due in lecture in 2 weeks – Oct. 9.

This week’s lab (Lab 6) has a pre-lab assignment. We will work it in class today.

Q1 – What date is PDM 1 due?

4

Equipment Checkout

This week you will get your TX, RX, and MC

Checked out to Team Leader. Need Banner ID and phone #.

You can leave these in lab if you prefer.

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Motors

Everything you ever wanted to know about Lego motors –

http://www.philohome.com/motors/motorcomp.htm

Some Diff Eq thrown in: http://nxt-unroller.blogspot.com/2011/01/motor-controller-

with-feed-forward-for.html

6

Lego Car Project

Wirelessly driven Lego car

Left and right channels/motors for steering

Goal is to navigate and finish course as quickly as possible

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START/FINISH

BLOCK

Required Gates

Optional Gates(+5 sec. penalty if missed)

Push block across finish line or incur a +30 sec. penalty

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Lego Car Overview

Receiver

R1, R2

PPM

PWM

PWM

Motor Control Board

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Pulse Width Modulation

Vo determines maximum motor speed. Larger Vo makes car go faster, but there are penalties for Vo above 10V.

Set Vo with a voltage regulator on the motor control board.

Vo

Vo

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Motor Control Board

Voltage regulator outputs a constant voltage Vo as long as Vin > Vo + 1.5 V.

Set Vo by choosing resistors R1 and R2.

R1 Vo

- Vi + Motor2 Motor1

R2

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LM 338 voltage regulator data sheet

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Voltage Regulator

Vref and Iadj are given. Choose R1 and R2 to set Vo. In lab, R1 will be given and you will vary R2.

» In the competition, you can choose both R1 and R2» Only certain values of resistors are available

ref 2 1 adj 21 /oV V R R I R

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Quiz Pause….

Q2 – What determines the voltage regulator output?» (a) Resistor values» (b) Position of an adjustment knob» (c) Transmitter joystick

Write the letter of your answer and also the complete answer.

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Penalties

Penalties are a way to introduce “cost” into the design and cause the team to make tradeoff decisions.» Incurring a penalty should not be considered unethical or “wrong” in any

sense. 5 second penalty for missing a gate 30 second penalty if the block is not pushed across the finish line Penalty of 1 second for each 0.5 V over 10V in voltage regulator

output (Vo)» Vo ≤10.0V = no penalty» 10.0V < Vo ≤10.5V = 1 second penalty» 10.5V < Vo ≤11.0V = 2 second penalty» etc.

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Q3 – What is the purpose of penalties in competition scoring for ENGR 1110?» (a) Punish the unethical» (b) Introduce cost and force tradeoffs

Write the letter of your answer and also the complete answer.

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Lego Car Design Output voltage

» Higher output voltage increases speed» Penalties apply above 10V

Power supply (batteries)» One 9V battery (light, but less than 10V)» Two 9V batteries (≥10V, but heavy)» Watch batteries (very light, but drain quickly)

Wheel size and gears» Torque vs. speed tradeoff

Drive strategy» Front wheel vs. rear wheel drive

Course path» Passing through all gates vs. missing gates» Pushing block vs. not pushing block

Body» Light vs. heavy

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Tables/ Spreadsheets/Graphs

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Tables vs. Graphs

Tables are an effective method for organizing and presenting design data.

Tables are good for recording and calculating precise numerical results.

Tables can be created conveniently in MS Word® or Excel®.

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Tables vs. Graphs

Graphs are effective for showing trends in the data

Graphs are effective for visually interpolating “in between” values

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Tables vs. Graphs

Q4 – Trends in data are best shown through » (a) Graphs» (b) Tables

Q5 – Precise numerical values are best shown in» (a) Graphs» (b) Tables

Write the letter of your answer and also the complete answer.

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Tables vs. GraphsTime (s) Distance (m)

0 1 2 3 4 5 6 7 8 9

10 11 12

0.0000 0.4647 1.2112 2.0114 2.8241 3.6408 4.4609 5.2812 6.1017 6.9219 7.7425 8.5630 9.3842

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Tables vs. Graphs

0

1

2

3

4

5

6

7

8

9

10

0 2 4 6 8 10 12 14

Time, sec.

Dist

ance

, m

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American Wire Gauge

Resistance per unit length increases with gauge

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Tables vs. Graphs

0

1

2

3

4

5

6

0 2 4 6 8 10 12 14

AWG

Ohm

s/km

25

Wire Gauge Table (1" = 25.4mm)AWG* diameter

mmarea mm2 Amps for

450A/cm2ohms/km@ 20Camb

0 8.252 53.490 240.70 0.3222 6.543 33.620 151.30 0.5134 5.189 21.150 95.18 0.8156 4.115 13.300 59.85 1.3008 3.264 8.367 37.65 2.100

10 2.588 5.261 23.67 3.30012 2.050 3.310 14.89 5.250

Tables

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Table Formatting

Use the fewest lines necessary to guide the eye for a cleaner look.

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More lines than needed…

Wire Gauge Table (1" = 25.4mm)AWG* diameter

mmarea mm2 Amps for

450A/cm2ohms/km@ 20Camb

0 8.252 53.490 240.70 0.322

2 6.543 33.620 151.30 0.513

4 5.189 21.150 95.18 0.815

6 4.115 13.300 59.85 1.300

8 3.264 8.367 37.65 2.100

10 2.588 5.261 23.67 3.300

12 2.050 3.310 14.89 5.250

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Cleaner layout

Wire Gauge Table (1" = 25.4mm) AWG* diameter

mm area mm2 Amps for

450A/cm2 ohms/km @ 20C amb

0 8.252 53.490 240.70 0.322

2 6.543 33.620 151.30 0.513

4 5.189 21.150 95.18 0.815

6 4.115 13.300 59.85 1.300

8 3.264 8.367 37.65 2.100

10 2.588 5.261 23.67 3.300

12 2.050 3.310 14.89 5.250

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Table in MS Word

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Table in MS Word -- Result

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MS Word Tables

Tables in MS Word are STATIC Potential problem:

» Values in the table are related by a formula» A value in the formula changes

In MS Word, all the affected values must be recalculated and re-entered manually.

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Table in MS Excel

Excel is a table!

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Tables in Excel

Excel inherently organizes material into tables.

Tables can actually calculate entries automatically.

Numbers can easily be formatted to reflect the proper type of data and precision.

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Excel Table Example Ideal weight for a 5’0” male

» 110 lbs.

For every inch above 60” (5’0”)» Ideal weight increases by 5 lbs.» Ideal weight = 110+(height-60)*5

Create a table of ideal weights for heights from 60” to 78”

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Excel Table Example

Formulas Absolute references Sizing of rows and columns

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Another Excel Example

Car payment» Loan Amount» Interest Rate» 3 year (36 month) duration

Compute» Payment» Amortization schedule

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Pie Chart Example

New-hire engineer assignments

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Last Slide

Q6 – When and where is your skit due?

Ans: Tues. Oct. 16 by noon to Canvas