The document describes the development of an inbuilt weighing device for travel bags by a team named 'Let's Do It' from the Sant Longowal Institute of Engineering and Technology. The device aims to address the common problem of luggage weight measurement, utilizing a digital weighing system based on strain gauge load cells and Arduino technology, with a competitive analysis on vendor-based versus Arduino-based scales. The project supports the 'Make in India' initiative, contributing to job creation and showcasing a dedication to technological innovation in the luggage industry.

1. Inbuilt Weighing device 1.0
for travel bags
• Team Name: Let’s Do It
• Members:-
1. Mohammad Tanveer / 1933530
2. Shubham Mehta / 1933536
3. Harshraj / 1933528
4. Krishna Kumar Yadav / 1933513
5. Azad Ranjan / 1933531
techFest’21
• Sant Longowal Instituteof
EngineeringAnd Technology, Punjab.
• Domain:karyarachna
• Event: Market kshetra

2. Content
1. Introduction
2. Science Behind Measuring System
3. Digital Scale Working
4. Deforming the Strain Gauge
5. Conversion to Electric Energy
6. Pictorial View of How it Look From Inside
7. Trolley Top View How it Look
8. Arduino based weighing system
9. Prices of Both Vendor Based Weighing Scale vs Arduino Based
10. Conclusions

3. INTRODUCTION
❑ Lot of us when travel to airport so thereis a problemof luggage weight measuring so we as a team is
dedicated towards making our world a better place to live through normal concepts. So From where this
idea originated it is originated from the lockdown days because we as a mechanical engineer always
think that how to make a object easy and handy to use. So we have tried to rolled out the
trolley/luggage bag with weight measuring inbuilt 1.0. Overall a good approach has been tried to made
from our side to help shaping our economy better.
❑ The Trolley if its weight is suppose2kg without luggage than with inbuilt measuring system it would be
close to 3kg.

4. SCIENCE BEHIND
MEASUREMENT SYSTEM
❑ How Does a digital weight measuring system weight?
So many of u are knowing or not that through contact force we measure weight of any object many of you
are thinking contact force we want to say the force between the object and the measuring scale.
❑ Whatis the major component behind the digital weighing system?
Strain gauge load cell

5. DIGITAL SCALE WORKING
❑ Digital scales work with the use of a strain gauge load cell. Whereas analog scales use springs to
indicate the weight of an object, digital scales convert the force of a weight to an electric signal. Its key
componentsconsist of a strain gauge, a device used to measure the strain of an object, and load cell
sensor, an electronicdevice used to convert a force into an electrical signal. A load cell is also known as
a force transducer.
❑ When an item is placed on the scale, the weight is first evenly distributed.Under the flat tray of a digital scale you
might find, for example, four slightly raised pegs in the corners that serve to distributethe force of the weight
evenly. The mechanical design of the digital scale then applies the force of the weight to one end of a load cell. As
the weight is applied, that end of the load cell bends downwards.

6. DEFORMING THE STRAIN GAUGE
❑ The force of a weight then deforms the strain gauge. The strain gauge can consist of metal tracks,
or foil, bondedto a printed circuit board or otherbacking. When the metal foil is strained, the
backing flexes or stretches.

7. CONVERSION TO ELECTRIC SIGNAL
❑ The strain gauge then converts the deformation to an electrical signal. Because the load cell has an
electric charge, as it moves downwards, the electrical resistance changes. The resulting small change
in resistance becomes an electrical signal. The signal is run through an analog to digital converter, and
then passes through a microchip that "translates" the data. As a result of this final calculation,numbers
indicating the weight of the object appear on the LCD display of the digital scale.

8. PICTORIAL VIEW OF HOW IT
WILL LOOK FROM THE INSIDE
❑ In the two side of the bottomsurface we put the strain
gauge load cell and there the microchip which act as a
sensor for weight measurement is present after joining
both of them with a lcd both load added up and in the
display we can see. We are making economical so we
are sourcing parts from the vendor who is industrial
standard in weighing system.
❑ Second method by using Arduino we can make but by
this it is not economical and also fragile.

9. TROLLEY TOP VIEW HOW IT LOOK

10. ARDUINO BASED WEIGHING SYSTEM
❑ The Signal Conditioner
This is a circuit device that has two functions. It amplifies load cell outputvoltage and filters both its input and
outputsignals. Since the output of the load cell is always very small, measured in mV, this device is critical to
amplify the load cell outputto a usable level. Load cell signal processing requires a special type of amplifier
called the instrumentationamplifier. The filter circuit can be embedded together with the amplifier on a single
chip. This circuit filters noise signals and electromagnetic interference(EMI) that might compromise the load
cell’s amplified signal. It decouplesAC signals from the DC outputsignals. Tacuna Systems offers a signal
conditioningdevice described at this link.
❑ The Microcontroller
This is the central processing unit of the whole digital scale. The analogoutputof the signal conditionerflows to
the analog input port of the microcontroller, which in turn converts this analogsignal to digital. Note that some
signal conditionershave an analog to digital converter circuit together with the amplifier circuit and the filter
circuits on a single chip. This reduces the workload on the microcontroller,as the outputof the signal conditioner
instead goes to the digital input port of the microcontroller. The microcontrollerthen reads the clocked digital
pulses from the conditionerto obtain the data it processes to determine the weight displayed. Finally, the
microcontrollercomputes the weight and then displays it through its connectedLCD screen.

11. ❑ The Liquid Crystal Display
o Coupling These Components
o To build a digital scale yourself, we will use the following components coupled together:
o A 5kg load cell
o An HX711 amplifier
o An Arduino Uno Microcontroller Unit (MCU)
o Any suitable output screen (in this case an Arduino IDE Serial Monitor)
o The physical process to build the digital scale is outlined in the next two steps.
❑ The Hardware Setup
o The 5kg load cell for this project has four wires (some load cells have 5). The wires are as follows, according to the
load cell’s datasheet.
o Red wire is the positive power supply
o White wire is the Ground of the power supply
o Black wire is the positive output
o Green wire is the negative output
o Any extra wire, which might be any color such as blue or yellow, is the ground wire for EMI. It should be connected to the
power supply ground.
o Note the wiring diagram depends on the datasheet of the purchased load cell. Therefore the colors listed above could
match differently (such as green being positive, etc.). Be sure to always request a datasheet from your supplier with your
purchase.

12. ❑ Load Cell to Amplifier Connection
o The wires listed above attach to the appropriate pins of the HX711 amplifier device as shown in the sets of pictures below. The
HX711 is a special amplifier that has 2 channel inputs A and B, each with different amplifier gains adjustable by a computer
program. The channel A has a gain of 128 and 64, while the channel B has a fixed gain of 32.
o Note this HX711 device matches the description of the type of signal conditioning device that has an amplifier, filter, and ADC
embedded together on a single chip. This means its data output goes to the digital input pin of our microcontroller instead of its
analog pin.
Therefore, connectingthe HX711 and the load cell is as followed:
o Red wire/Positive supply -> E+
o White/Negative Supply -> E-
o Green/Negative Ouput -> A-
o Black/Positive Output -> A+
Load Cell to Amplifier
Connections
Amplifier to MCU
Connections
o Amplifier to Microcontroller Connection
o After connecting the amplifier, the next step to build the
digital scale is to connect the microcontroller. The HX711
connects to the Arduino MCU as follows:
o VCC -> 5V supply on Ardunio
o GND ->GND
o CLK -> D2
o DOUT -> D3

13. ❑ The Code
o Once the hardware connectionsare complete, the next step to build the digital scale is to uploadthe program code
to the MCU from a PC through theArduino IDE. The process and the code have two subdivisions: the calibration
code and the weighing code.
❑ Calibration Code
o The calibration codeis the program used to calibratethe load cell transducer. Calibrationconfigures the load cell
outputto always give a precise value of weight and at the particularS.I unit such as Kilograms, Grams, Tons,
Poundsetc.
o The HX711 library code containsa good guide on how to calibratethe load cell.
o The results of the calibration process are shown below in the Serial Monitorof theArduino IDE.

14. HX711 CalibrationCode

15. ❑ Weighing Code
o Once calibration is complete, the weighing code uploadsto the MCU. This code appears in Figure 8 below. The
figures that immediately follow, Figures 9a-b, show the readoutsfor a 500g weight (top)and a 1kg weight
(bottom).
Digital Weighing Scale Output

16. PRICE OF BOTH VENDOR BASED
WEIGHING SCALE VS ARDUINO BASED
VENDOR BASED
1. ECONOMICAL.
2. NOT UPGRADABLE.
3. CORRECT READING CALIBRATED.
4. NEED ONLY 2 AA BATTERY TO
OPERATE.
5. CONSTRUCTION IS SIMPLE .
6. CHANCES OF ERROR IS NEGLIGIBLE.
7. TROUBLE FREE OPERATION.
8. IF PROBLEM ARISES THAN VENDOR
CAN ONLY OPERATE.
9. OVERALL COST TROLLEY+KIT=3500
WITH 97CM SIZE OF TROLLEY.
ARDUINO BASED
1. NOT ECONOMICAL.
2. UPGRADABLE.
3. CORRECT READING UPTO TO DECIMAL
PLACES.
4. NEED LARGER CELL .
5. CONSTRUCTION IS HARD.
6. ERROR IS MORE.
7. MAY TROUBLE IN FUTURE.
8. IF PROBLEM ARISES IT WILL BE EASY
TO IDENTIFY.
9. OVERALL COST TROLLEY+KIT=5500
WITH 97CM SIZE OF TROLLEY

17. CONCLUSION FOR BOTH VENDOR WEIGHING
SYSTEM AND ARDUINO BASED SYSTEM
o Everything has it pros and cons we are not getting into that for information you all can google and search every
where this type of inbuilt weighing system does not available at all we have tried to implement it in both way
through vendor and through Arduino also in a luggage bag/trolley. The main thing if u focus on this product is that
it just cutoff the dependencyof weight measuring and hence overall improve the user experience. By making this
development we are taking technologies and comfort to the othernew level. This is our first model we are working
on 2.0 for further enhancingthe user experience. Hope in the upcoming year we will immerse as major brand in
luggage industry for creating technological related products.In this we all learnt that nothingis impossible and only
required true dedication.

18. ORGANIZATION STRUCTURE/HOW IT WILL HELP
INDIA
So First of all our brand name as we decided is SWATANTRA LUGGAGE TECHNOLGY it will be exclusive to
onlinestore only we are following b2c in this. We have decided that all 5 of us will head the organization
And we have tied up with VIP bags for supply and currently we are hiring around 10 employs 2 for data
feeding,3 site maintenance,3 assembler and 2 packager additionallywe require other staffs but that is a
matter of time. Now coming to is it make in INDIA off course all major development all thing have been
done in INDIA itself all parts are made in INDIA and we are proud to say that we are helping INDIA for
shaping it economy better by creating jobs and by creating good products we are proud to say we are the
members of let’s do it who have think so far in right direction for completion of the project.
As per part of information but that is not to shared but still our vendor is Hoffen.

19. THANK YOU