Electrical circuit exercise report traffic light circuit design

"NHáƯO CHÃẼN HÃỂNH SCHEMATIC VAAO AOAAY NHA" The construction of 4-way traffic circuit include three main blocks: ¢ Source block: Our team have decided the voltage threshold for high vo

NATIONAL UNIVERSITY OF HO CHI MINH CITY

HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY COMPUTER SCIENCE AND TECHNOLOGY

4444443 * 4444444

BK

TP.HCM

ELECTRICAL CIRCUIT EXERCISE REPORT

TRAFFIC LIGHT CIRCUIT DESIGN

Instructor: Huynh Hoang Kha Students:Team 10

Ha Trung Quyen - 2014314 Dang Gia Thinh - 2014591 Lau Sam Tuong - 2015007

HO CHI MINH CITY, 12/2021

Danh sách bang

0805 packed resistor datasheet 2 2 ee ee 22

0805 packed footprintinalttum 2 0.0 000.000.0004 23

0805 packed resitor 3d body © 2 ee ee 23

0805 packed resitor 3d body © 2 ee ee 23

diode led datasheet 2 2 ee v va 29

The internal logic construction of 55ŠSIC 34 555ICastableímode .Q Q Q Q Q Q Q Q Q vv va 35 555ICastableímode .Q Q Q Q Q Q Q Q Q vv va 35 555ICastableímode .Q Q Q Q Q Q Q Q Q vv va 36 555ICastableímode .Q Q Q Q Q Q Q Q Q vv va 36

NESSS5D IC on the market 2 2 eee 38 NESSSDIC Datasheet 2 2 ee ee 39

luF polarized capacIOT Q Q Q Q Q HQ va 42 Capacior datasheet Ặ Q Q Q Q Q HQ HH rẻ To 43

SN74SL192 On the market 2 Q Q Q Q Q Q Q 50 SN74LS247 on the market Ặ Q Q Q HH SỦ 51 CD4071BM onthe market 2.2.0.0 0 0000 00.0004 52 CD4071BM footprint datasheet 2 2 ee, 52

CD4071BM 3d body 2 2.2 .022000.2 0.2 00 0.0.00 0040 53 CD407IBM3DBody O QQ Q 200000 54 74HC14D onthe market 2 2 0.2.0.0 00 0 00000 54 J4HC20D onthe market 2 ee 55

Chuong |

Introduction

1.1 Preface

The development of technology has not stopped completely changing the world in terms

of people, perceptions, skills We need to go back to the early history of basic technology, when we were children when we were young Surely everyone has wondered about things going

on around them, like how does a traffic light work, hidden deep inside the circuit, how does it work? Since then we’ve had it consciously learn and feel this issue is practical, interesting The effect of traffic lights is extremely important in distributing traffic, avoiding traffic jams, traffic accidents, etc We will implement this project based on the knowledge learned from the electronic circuit department to gain insight into how it works and enhance your expertise

1.2 Requirements

Propose an idea to design a circuit board consisting of the following 3 functional blocks:

- Power supply block

An overview of the idea

- Design the schematic diagram (explain more if necessary)

- Component selection, each component is selected, clearly explaining the reason for selec- tion, along with parameters of size, footprint, 3D image

- Set PCB design rules (including track widths, clearances, ) and explain the setting of design rules

PCB layout

- Export 3D images

Comment on results, learn from experience, and draw conclusions

1

1.3 Report layout

- Chapter 1: Introduce about the topic

- Chapter 2: Introduce and explain each function block contained in an electrical circuit Then steps to design a electrical circuit

- Chapter 3: Realistic, overall review of the finished product

- Chapter 4: Summary What do you get after completing a design?

Chuong 2

Design

2.1 Overview each block

Aw?

"NHáƯO CHÃẼN HÃỂNH SCHEMATIC VAAO AOAAY NHA"

The construction of 4-way traffic circuit include three main blocks:

¢ Source block: Our team have decided the voltage threshold for high voltage level will be 9V and low voltage level will be OV For this reason, we use regulator IC to generate a fixed 9V input source

¢ Peripheral block: Control the circuit and displaying the result

2.2 Design each block

VN Output Noise Voltage f = 10 Hz to 100 kHz, Tạ = +25°C 42 uV

2 Load and line regulation are specified at constant junction temperature Changes in Vo due to heating effects

must be taken into account separately Pulse testing with low duty is used

3 These parameters, although guaranteed, are not 100% tested in production

Hinh 2.1: LM7805’s data sheet Design the source :

¢ About LM7805CT, the LM7805CT is a Linear Voltage Regulator A voltage goes in one side, and a smaller voltage goes out from the other side

For this regulator to work functionally, the voltage difference between input and output voltage must at least more than dropout voltage Our input voltage is 22V (220V after transformed using potential transformer and rectifier ), so this requirement is met The next thing to consider is choosing capacitors to maintain stability of the regulator and smoothing the ripple

The input capacitors is needed to prevent the voltage from dipping below the drop-out voltage and to attenuate any high frequency noise Because the input 22V only just going through the rectifier, so in this circuit, to stabilize, two capacitors: 470uF one to store large charge and the 0.01uF to handle high frequency noise

* 0.01uF capacitor is also used on output side of the regulator to prevent noise

From the explaination above, our team construct the source block as follow :

Components require :

* LM7805

¢ Aluminum capacitor 470uF

¢ Non-polar capacitor 1OnF x2

* Recifier diode bridge

a) LM7805

¢ Output Voltage from 4.80min to 5.2max

* Ouput current 1A

¢ Max input voltage 50V

¢ Package style TO-220-3

a LM/8USC I-CN IC On Ap 5V 1A

Bign ap vao: 7.5-35VDC, điện áp ra: 5VDC, TO-220 / Thương hiệu: OEM Báng giá Hàng còn: 4 Cái Số lượng mua (Giri hang trong ngày) (Cải)

1+

Số lượng mua: - 1 +

20+

Thém vao gid hang 50+

® Yêu thích ÐỒ Siao hàng toàn quốc

W Cam két dura nang

Hinh 2.4: LM7805 on the market

Don gia

(VND) 6.000

5 900 5.800 ang

SUPPLIER "B" PACKAGE SHAPE Ø4.00

350 10,67

Hinh 2.6: LM7805 footprint size

Hinh 2.7: LM7805 3D body

Hinh 2.8: LM7809 3D body

b) Aluminum capacitor 470uF

¢ Capacitance value 470uF

Thương hiệu: OEM

(Gửi hàng trong ngày)

Số lượng mua: 1

„ Thêm vào gid hang

9 Yêu thích oPnanh ROWS fF] &

Số lượng mua (Cái) 1+

2450 2.400 2.350

cop Thanh toán khi nhận hãng

}% Cam kết đổitrả hàng

Hình 2.9: 470uF Capacitor on the market

i Dimensions in mm (not to scale (Unit : mm!

pea D L A8 b ' w £ K

B | 40] 58203 | 43| 55 max | 1.8 | 0.6520.1 | 10 | 035'a4;

C | SO] 58203 | 53| 6S max | 22 | 065+0.1 | 1.5 | 0.3578

D | 63] 58:03 | 66| 78 max | 26 | 065z0.1 | 18 | 035'3) D@ | 63| 7.7203 | 66] 78 max| 26 | 0.6520.1 | 1.8 | 0.3574

E | 80] 62203 | 83] 95 max| 34 | 065201 | 22 | 0.35:38

F | 80| 102403 | 83| 100 max| 34 | 0.90202 | 3.1 | 0.70202

G | 100] 10.2203 | 103| 12.0 max.| 35 | 0.90202 | 46 | 0.7020.2 H13 } 125] 135205 | 135] 150 max | 47 | 0.90203 | 44 | 0.70203

316 | 16.0] 16.5205 | 17.0| 19.0 max.| 55 | 1.20203 | 67 | 0.70203 K16 | 18.0] 165205 | 19.0] 21.0 max | 67 | 1.20203 | 67 | 0.70203

¢ The footprint type of this capacitor is H13 :

=> y~-~y L

® Vibration-proof products When size “a” is wide, back fi llet can be made, decreasing fi tting strength

< Size code : D, D8 > c

* Take mounting conditions, solderability and fi tting strength into

consideration when selecting parts for your company’s design

* The vibration-proof capacitors of size 06.3 has support terminals extending

from the bottom side to the lead edge Then, make sure to find appropriate soldering conditions to form fillet on the support terminals if

‘sign and specifications are each subject to change without notice Ask factory for the current technical specifications before purchase and/or use

Hình 2.11: 470uF aluminum capacitor datasheet

* follow this footprint guide, our pad in altium will like this:

á J’ : Hàng còn: 416 Gói(10con) Số lượng mua Đơn giá

‘Tia (Sal 00) over Nickel (Nid

Quick View Side View Detail

Hình 2.17: capacitor with 0603 footprint

¢ Note*: All the non-polar capacitor with 0603 used in this circuit will have the same foot print and datasheet as sated above

Hinh 2.18: 0603 capacitor 3d body

Hinh 2.19: 0603 capacitor with 3d body

2.2.2 Peripheral block

Restart button:

¢ The button is constructed using "debouncing" button design

* Restart button will Restart the circuit when press This unit will connect to the master reset pin of counting ic in this circuit

* Because all the counting ic (74192 and 4017) have high active master reset pin, so we will need a reset button with high signal when press

Design the Restart button:

¢ To have switch button with low signal (OV) when idle and high signal (SV) when press,

we will need a pull down resistor ( a resistor connect straight to GND )

Note*: The reason why we choose 10k resistor is explained below:

3 When pressing the button, without the resistor, the source will directly connected to ground Short circuit like this will be damaged and burn

G) To prevent that, we add a resistor to limit the flow of current

G) Such resistor is called a pull-up resistor because it is connect directly to source and help protecting the circuit

G) Most digital circuits use a 10k or a 47k resistor for pull-up The exact value doesn’t actually matter, as long as it is high enough to prevent too much current from flow- ing 10k seems to be the most common as we need this signal strong enough to drive multiple logic ics

But one more thing to consider is the changing of voltage level When press and release the button, the sudden change of voltage is too fast, and sometime ic may miss the signal

To solve this problem, we add a non-polar capacitor next to the switch The charge and dis- charge ability of the capacitor will slow down the changing of the voltage, hence improve the stability of the button

The switch will connect straight to source, and is placed right above the pull down resistor The logic output which is used for resetting this circuit will be taken out from point A right between the switch and the resistor

When the switch is open, the voltage level of point A will be 0 (GND) and when we press the level, the voltage level will become 5V

From the explaination above, our switch button are designed as follow:

15

— CS 10000pF

¢ Switching capacity 1 to 50 mA, 5 to 24 VDC

¢ Contact form SPST (single pole, single throw)

* contact resistance is 100 m 2 max and insulation resistance is 1OOM & max

16

B3F-4055 Nút Nhắn 12x12mm Cao 7.3mm 4 Chan Xuyên Lỗ Omron

12VDC 500mA

Thương hiệu: Omrnn Bảng giá

Hàng còn: 9673 Cái Số lương mua Đơn gá (Gửi hàng trong ngày) (cai) (VND)

1+ 2.500

Số lượng mua: - 1 +

Thém vao gid hang 100+ 2.400

9 Yêu thích ® Siao nàng toàn quốc

— coo Thanh toán khi nhận hàng

0 Phản hỏi —©

]W cam kết adit nang

Hinh 2.21: 12x12 tactitle switch on the market

Projected Plunger Type (without Ground Terminal)

B3F-4050, B3F-4055, B3F-5050, B3F-5051

PCB Mounting (Top View) T—12+°? (Single-sided PCB, t=1.6)

Hình 2.23: Button footprint Note* : The distance between two pin is 5mm

Hình 2.24: Button footprint

18

Hình 2.25: Button footprint Note*: The diameter of position boss is 1.9mm

Hình 2.26: Button footprint Note*: The diameter of all four pin is 1.2mm

19

` Thương hiệu: Y2geo Bảng giá

af Hét hang (Dat mua đề có Số lượng mua Đơn giá

z Thôm vào giỏ hàng 200+ 1.750

® Yê‹ thích ® Giao hàng toàn quốc

W Cam két d6itra hang

Hinh 2.30: 100nF capacitor with 0603 packed on the market

¢ Note*: The datasheet and foot print of 0603 was stated above

Hinh 2.31: 10k resistor on the market

SOLDER PAD DIMENSIONS

RECOMMENDED SOLDER PAD DIMENSIONS

22

Displaying unit:

¢ For the displaying block, we use 7-segment led to display the time and 3mm diode led with red, green and yellow to represent the color of traffic light

* 3mm diode led also use to displaying the status of pulse generator

Design the displaying unit:

* Because the 7-segment led only require 20mA to function, so we will only use the resistor

to limit the current from ic

¢ On the other hand, to drive the diode properly, the current form the ic through the 1k resis- tor alone is not enough Therefore, NPN transistor will be used as amplifier to strengthen the signal from the ic

® 10k resistor are used to limit the output current of ic and NPN BJT are used as amplifier

to enhance the current

* Diode also require to prevent the reverse current, protect the led

From the explanation above, the displaying unit will appear to be like this:

Hàng còn: 188 Cái Số lượng mua Đơn giá

(Gửi hàng trong ngày) (Cái) (VND)

Số lượng mua: - 1 +

® Yêu thích © Giao hang toàn quốc

LED Đỏ 3mm Duc Chân Ngắn

Hết hang (Dat mua dé cd nưa Bon gid

3 Thương hiệu: OEM Bảng giả

É Hét hang (Dat mua để có Số lượng mua Đơn giá

d) NPN BJT (cha% 1AOm)

e) 1N4007 Diode

¢ SMD type

s forward voltage: 1.1V

¢ Maximum reverse voltage: 1000V

¢ Average current flow: 1A

1N4007-M7 Diode Chinh Luu 1A 1KV

Thương hiệu: Toshiba Bang gia

2.18 4.775

§.49 _~

Recommended Land Pattern

33

2.2.3 Logic block

Clock generate unit

¢ Every single ic in the counting unit have to be driven by clock pulse For the ic to count exactly every is, we need a 1Hz clock

* Therefore, to generate 1 Hz, our team decide to use IC NE555D timer circuit

¢ The internal of NES55D is show in the figure below:

|

N

i 4

+

Hình 2.52: The internal logic construction of 555 IC

¢ First we have to take a look at how this ic work :

3 The first comparator negative input terminal is connected to the 2/3 reference voltage

at the voltage divider and the external "control" pin, while the positive input terminal

to the external "Threshold" pin

G) On the other hand, the second comparator negative input terminal is connected to the "Trigger" pin, while the positive input terminal to the 1/3 reference voltage at the voltage divider

G) So using the three pins, Trigger, Threshold and Control, we can control the output

of the two comparator which are then fed to the R and $ inputs of the flip-flop

G) The flip-flop will output 1 when R is 0 and Š is 1, and vice versa, it will output 0 when R is | and $ is 0

G) Additionally the flip-flop can be reset via the external pin called "Reset" which can override the two inputs, thus reset the entire timer at any time

3 The Q-bar output of the flip-flip goes to the output stage or the output drivers which can either source or sink a current of 200mA to the load The output of the flip-flop

is also connected to a transistor that connects the "Discharge" pin to ground

34