mfgg-135, ece lab2 pwm servo driver board...

Electrical and Computer Engineering Department

Kettering University

IME-100

ECE

Lab 2

2-1 G. Tewolde, IME100-ECE, 2017

Getting Started 1. Laboratory Computers

i. Log-in with User Name: Kettering Student (no

password required)

ii. IME-100 information (Lab presentation, files, etc.) in folder

on desktop

iii. NI programs (MultiSim, Ultiboard) under the Start menu

iv. At the end of lab, Logout of computer; arrange keyboard

and mouse

2. Laboratory Instrumentation

i. Use instrumentation only when instructed

ii. At the end of lab, turn instrument power off, neatly arrange

leads on bench


IME-100, ECE Lab2

Circuit Board Assembly and Test

In this laboratory exercise, you will do the following:

• Read and interpret the schematic diagram of a traffic light

circuit

• Identify common electronic components

• Assemble/solder a traffic light printed circuit board

• Perform a functional test of the traffic light circuit using

standard laboratory equipment/instrumentation

• Debug the circuit if necessary


Traffic Light Printed Circuit Board

3D visualization of PCB design

Actual PCB


G. Tewolde, IME100-ECE, 2017

Siren Circuit Schematic Diagram

2-5

Traffic Light Circuit Kit Parts List

• 1 Traffic light PCB

• 1 LM555 Timer IC

• 1 4017 decade counter IC

• 1 4072 dual 4-input OR gate IC

• 2 10 mF capacitor

• 3 10 nF (0.01 mF) capacitors

• 1 120 Ω resistor

• 1 3.3 kΩ resistor

• 1 47 kΩ resistor

• 1 100 kΩ potentiometer

• 1 green LED

• 1 yellow LED

• 1 red LED

• 1 6-pin header

• 1 8-pin IC socket

• 1 14-pin IC socket

• 1 16 pin IC socket



Resistors and Capacitors

•Units of capacitance are Farads, (F).

•Values in μF (microFarads) or nF (nanoFarads).

•Two types of capacitors used

1) C1 is electrolytic (polarized - μF values)

2) C2, C3 and C4 are polyester or ceramic disk (non-

polarized - nF values)

•¼ W resistors. Values in Ω (Ohms) or kΩ (kilohms).

•Values indicated by color code

2-7

Capacitors

•Capacitance value

indicated by numerical

code or literally printed

on package

•Voltage rating is

important and either

encoded or printed on

package

Capacitors temporarily store electrical charge (called charging up the

capacitor) for release back into the circuit at a slightly later time

(called discharging the capacitor). Capacitors and resistors are often

used in combination to control how fast charging and discharging can

take place.

Electrolytic

Ceramic Disc

Negative lead is

marked on package.

Negative lead is

also cut shorter

than the positive

lead. Not polarized

Polyester


Polyester and Ceramic Disc

Capacitors

Polyester and Ceramic Disc capacitors are non-polarized. Their

orientation in a circuit does not matter. They have values less

than 1 mF. Their values are often represented by a numerical code.

101 = 100 pF 102 = 1 nF = .001 μF

221 = 220 pF 103 = 10 nF = .01 μF

331 = 330 pF 104 = 100 nF = .1 μF

471 = 470 pF

Capacitor Code

10 3

2A103J


Electrolytic Capacitors Electrolytic capacitors are polarized, i.e. they have a positive, +, and

a negative, -, lead. They MUST be connected into a circuit with the

correct orientation. They have values greater than 1 mF. Their value

and the negative lead are marked on the side of the capacitor. The

negative lead is also cut shorter than the positive lead.

+

-

C = 10 mF

Negative lead is

shorter

Capacitance

value, voltage

rating, and – sign

marked on side of

package


Resistors

•Resistance value usually

indicated by color code

•Physical size determines

power rating

Resistors allow designers to incorporate a known amount of resistance

into a circuit in order to limit the current flow or to generate a particular

voltage level.

¼ W resisor


Resistor Color Code


Resistor Color Code

2nd Band

4th Band

Example:

•First color band is Brown = 1

•Second color band is Black = 0

•Third color band is Red = x100

•Fourth color band is Gold = 5% tolerance

•Resistor value is 10 x 100 = 1,000 Ω = 1 kΩ

±50 Ω (i.e. 950 Ω < R < 1,050 Ω)

3rd Band

1st Band


Resistor color codes for Traffic Light Circuit

1 120 Ω resistor Brown Red Brown Gold

1 3.3 kΩ resistor Orange Orange Red Gold

1 47 kΩ resistor Yellow Violet Orange Gold

Qty Value Color Code

Exercise:

Fill in the appropriate Color Code







Exercise:



Variable Resistors or

Potentiometer (Pot) • A potentiometer is a three-terminal resistor with a sliding or

rotating contact. It provides variable resistance value between

one end of the device and the wiper.

• Pots are useful for applications such as volume, brightness,

and speed control.

• In the traffic light circuit the 100 KΩ potentiometer is used to

allow the user to change the speed of the pulses generated by

the 555 timer module. This in turn helps to control the

switching speed of the traffic signals.


Integrated Circuits, ICs

•ICs combine all the basic

electronic components into a

complete miniature circuit

fabricated on a single piece of

semiconductor material

(silicon). Thousands of very

complex circuits can be

fabricated on small silicon chips

simultaneously. These circuits

are reliable, operate at high

speed and are relatively

inexpensive.


Integrated Circuits, ICs ICs come in a variety of packages. One of the most common is the

Dual-In-Line (DIP) package. ICs must be properly oriented on the

circuit board. The pins (leads) are numbered according to a scheme

tied to an index mark on the package.

•Usually a notch

index mark indicates

the head of the chip.

Pin 1 will be in the

upper left hand

corner.

• Sometimes Pin 1 is

marked with a small

circle indent mark

Notch index

Pin 1

Pin 1

small circle

pin 1

Indent mark


Integrated Circuits, ICs Once Pin 1 is identified, the other pins of the DIP follow according to

the pattern below. The highest numbered pin is always opposite pin 1.

8-pin DIP 14-pin

DIP

1

2

3

4

8

7

6

5

1

2

3

4

5

6

7

14

13

12

11

10

9

8



Assemble the Traffic Light Circuit

2-22


IC sockets

LEDs

Resistors

Capacitors

PCB

6-pin

header




Tools needed

Wire cutter

/wick

2-24

Step 1) Insert and solder the resistors R1, R2 and R3 in place.


Step 1) Insert and solder the resistors

in place. Start with R1, then go on to

R3 and R4, etc.


Step 2) Insert and solder the on-polarized

10 nF capacitors, C2, C3 and C3, in place.


Step 3) Insert and solder the polarized 10 μF

capacitor. The negative lead is cut shorter

than the positive lead and is marked on the

side of the package.


Step 3) Insert and solder the polarized 10 μF capacitor, C1, in

place. The negative lead is cut shorter than the positive lead and

is marked on the side of the package.

Positive terminal of C1is

marked on the board

Negative lead of C1 is

marked on the package


Step 4) Insert and solder the green, yellow and

red LEDs in place.


LEDs are polarized. The positive lead

ls longer than the negative lead. The

negative end is on the Fflat side of the

package.

Place the negative leads of the LEDs in

the holes closest to the board edge

Step 4) Insert and solder the green, yellow and

red LEDs in place.


(

Pin 1 index mark

Step 5) Insert and solder the 16 pin, 14 pin and 8 pin IC

sockets in place. There is a notch index that indicates the pin 1

orientation. (Use some tape to help hold the socket in place

when you turn it over to solder)


Step 5) Insert and solder the 16 pin, 14 pin and 8

pin IC sockets in place. There is a notch index

that indicates the pin 1 orientation.


Step 6) Insert and solder the 3-pin

potentiometer (variable resistor),

R4, in place.


Step 6) Insert and solder the 3-pin potentiometer (variable

resistor), R4, in place. If you place the potentiometer pins in

a different direction the way you turn the screw for increasing

or decreasing the resistance values will be reversed.

Pin 1 is on the

screw side


Step 7) Insert and solder the 6-pin

header, J1, in place.


Step 7) For convenience first insert the 6-pin header, J1, in a

breadboard, then place the PCB in place with the header

inserted in its socket. (The longer leads remain in the

breadboard. The shorter leads come out on the component

side of the PCB as shown in the figure)


Completed Traffic Light Printed Circuit Board

R3

R2

C1

C2

14

7 1

8 LM556

R4

R6

R7

C3

8 Ω Speaker

C4

4.3 V Power bus

Ground bus

-

+ -

-

+

Insert the 16-pin, 14-pin, and

8-pin ICs, in their sockets.

Align the notch index of the IC

to that of the socket. If it is

placed the wrong way the chip

could get damaged. Be careful

when inserting the chips so you

do not bend the pins. Ask the

instructor if you need help.


Functional Test of the Traffic Light Circuit

Arduino board

to provide 5V

power

Digital oscilloscope

with 2-channels


Functional Test of the Traffic Light Circuit…

Attach USB cord from a powered

PC to an Arduino on your desk.

This gives power to the Arduino.

To provide power to your traffic light

circuit, connect a wire from the Arduino

5V pin to the 5V pin of the PCB board.

And connect GND from the Arduino board

to GND of the PCB.

If the circuit assembly is done

correctly, you should see the

correct sequencing of the lights

on the LEDs. You can change the

setting on the potentiometer to

change the timing of the traffic

signals.

[Demonstrate for your instructor]


Functional Test of the Traffic Light Circuit…

Wirings to display signals

on the oscilloscope.

Attach another GND wire from the

Arduino to GND (Black) wire of one

of the oscilloscope probes.

Attach a wire from the

CLK pin of the PCB to

the red wire of channel

1 of the oscilloscope.

Attach a wire from Red (R) pin of the PCB to the

red wire of channel 2 of the oscilloscope.

5V and GND wires are

connected between Arduino

and the PCB



Functional Test of the

Traffic Light Circuit…

CLK

pulses

Red (R)

light

Repeat the test with the Yellow

(Y) and Green (G) lights

2-43

Homework: For the Curios You …

Due: Beginning of 3rd Week Lab

Think about ways in which you could improve

the functionality of the basic traffic light circuit,

by considering features that would be useful. Be

open to include additional inputs to control the

traffic light circuit in different ways.

Research and brainstorm your ideas with

your lab partners to cover many possible

scenarios.

Turn in a one page report for your answers.


Finishing Up (and to get full-credit in the lab)

1. Clean-up at bench – Leave it better than you found it!

i. Pick-up any spare parts, wire-trimmings, etc

ii. Detangle and coil wire leads

iii. Soldering stations and tools neatly arranged

iv. Turn off instrument power, arrange neatly

v. Logout of computer; arrange keyboard and mouse

vi. Neatly arrange the chairs

2. Check-out with the instructor

i. Leave the check-out sheet with your group names at

your station


Lab 2 Check-Out Sheet (to be left on the bench at the end of lab)

Group Members (please print name clearly):

Instructor (check all that apply):

□ Traffic Light Printed Circuit Board assembled

□ Functional audio test of Traffic Light Circuit

□ Functional Oscilloscope test of Traffic Light

Circuit showing CLK and one of the traffic light

signals (G, Y, R), one at a time.

□ Computer Logout

□ Bench clean-up

Wires, detangled and coiled,

Disposal of wire clipping, etc.

Soldering equipment arranged

Instrument power off and arranged

Keyboard and Mouse arranged

Chairs arranged

Additional Comments:


mfgg-135, ece lab2 pwm servo driver board...

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