TRC3500 Labs 2014 Lab Manual

Monash University

TRC3500 Sensors and Artificial Perception

Laboratory Documentation

Assessment:

Students are to work together in groups of TWO (2).

Please only submit ONE copy of the lab report for each GROUP. Clearly

Laboratory Exercise 4: Calculating Blob Statistics 5pm Fri 9 May 2014

Laboratory Exercise 5: Decoding an EAN-13 Barcode 5pm Fri 23 May 2014

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that occasionally circumstances will arise that will prevent you from handing in your

reports at the time you intended. For this reason I recommend that you hand in your

reports early. Late reports will be accepted up to 5pm on the Monday following the

due date. However, there will be a late penalty. Every attempt will be made to return

marks for the reports shortly after the last date for submitting late reports.

1. The report should contain a title, and brief description of the aims of the

project. In particular, the expected deliverables should be highlighted.

2. For the first three projects the sensor should be evaluated to identify its

characteristics. The results of this process must be documented in your report.

3. Your circuit design for processing the sensor signal should then be

documented.

4. Results demonstrating the capabilities of your sensor system should be

documented and analysed.

5. The report should conclude with a suitable conclusion.

In addition to the above components your report should be well laid out and

TRC3500 Laboratory Safety Procedures

General:

Never adopt a casual attitude in the laboratory and always be conscious of potential

hazards.

Never run in the laboratory or corridors.

Do not apply cosmetics in the laboratory.

Do not use laboratory apparatus without prior instruction on safe work procedures and

practices.

Do not lift heavy equipment (PCs, oscilloscopes) and always switch off power at the

GPO before unplugging equipment.

Observe safety signs at all times.

Keep benches clean and free from apparatus that is not being used.

Keep aisles free from obstructions – place bags in an appropriate location (under your

positioning of arms and mouse can minimise these effects. For more information see:

http://www.adm.monash.edu.au/ohse/assets/docs/guidelines/ergonomics-

computer.pdf

Do not “wheel” from one location to the next on chairs.

Let any co-workers or visitors know of hazards that exist in your work area.

Take care to ensure that electrical leads are not weakened by pulling and that plugs,

sockets, etc, are in serviceable condition.

protected.

Be aware that flashing lights or repetitive noise can precipitate seizures, e.g. Epilepsy.

When Soldering:

Wear safety glasses!

As far as possible, avoid inhaling the fumes given off when solder is melted.

under cold running water for at least 2 minutes.

The lead contained in solder is poisonous and therefore you should never place solder

in your mouth. Wash your hands after soldering and before eating.

In an emergency:

The big red button will cut power to the laboratory in case there is an electrical

hazard.

Introduction

In this exercise you will design, build and test a velocity sensor that will measure the

speed of a steel washer as it falls past an inductive sensor. The inductive sensor will

purpose op-amp circuits.

Equipment

The equipment that you will require should be available in a typical undergraduate

laboratory:

1) Oscilloscope

2) Multimeter

3) Soldering iron

Components

2) Magnet and enamelled wire

3) Restricted range of 1/8

4) A silicon diode

Recommended Procedure

In this experiment you are to construct an inductive sensor from the parts provided

and then to investigate the characteristics of the sensor and consider ways of

amplifying its output. A diagram of the sensor is shown below. As a first stage in the

process it is recommended that you examine the output of the velocity transducer

using an oscilloscope. Select a suitable angle so that the washer slides easily down the

plastic channel. Keeping the angle of tilt constant release the washer at different

distances along the channel and observe the pulse that the sensor produces as the

allows the capacitor C to charge on positive peaks of the input but prevents its

discharge when the input falls. Resistor R provides a discharge path for the capacitor

to reset the circuit. As an alternative you could use a shorting switch to discharge the

capacitor.

Introduction

In this exercise you will design, build and test a circuit to amplify the signal from a

strain gauge. The gauge will be mounted at the proximal end of a steel strip that will

The equipment that you will require should be available in a typical undergraduate

laboratory:

1) Oscilloscope

2) Multimeter

3) Soldering iron

4) Hook-up wire

5) 5V plug-pac (ensure that you do not short-out or overload the plug-pac)

6) Prototyping plug board

5) Restricted range of 1/8

Recommended Procedure

Using the g-clamp provided attach the steel strip to the edge of the bench as shown in

the following diagram:

material by observing deflection of the rule

when the weight is positioned at the end

of the rule (distance l from the gauge). You will recall the following equation:

2) Write a brief report that includes all of the measurements you made, your design

procedure, results and discussion. Each group will provide one common report with

an appendix indicating the contribution of each individual team member. Submit your

report before the due date.

Introduction

In this exercise you will write a program in C to grab an image of an EAN-13 barcode

using a USB camera, convert the image to grey-scale and scan across the centre of the

Equipment and Software

The equipment that you will require will be available in the computer laboratory:

1) USB camera

2) A PC

3) Microsoft Visual C++ version 6

4) OpenCV

5) The supplied skeleton program

I recommend that your program performs the following operations:

1) Grab and display successive images from the USB camera to allow the camera to

be focussed and positioned to get a good image of the barcode.

2) Leave the grab and display part of your program on a key press from the keyboard.

3) Convert the image to greyscale (a simple way to do this is to add the RGB

components of each pixel and divide the result by 3, returning the result to each of the

RGB components).

binary values. It would be a good idea to display the resulting binary image to ensure

that the barcode is correctly converted).

6) Count the number of pixels in each successive bar (in the binary image of the

7) You will be decoding the left-hand half of the barcode so for each of the 6

characters calculate the T-values for the character – converting measurements to

modules (T1, T2, T3, T4e and T). Note that T4e stands for T4 extended. This quantity

is used instead of T4 because it allows for spreading whereas T4 does not. To work

and ‘width of the first bar’ values.

9) Print out the character values and their parity.

If you have time (and for no additional marks) you could:

• decode the other half of the barcode

• work out the thirteenth character coded into the left 6 characters

• see if the check sum is correct

0) Attendance during the laboratory classes is compulsory and you will receive a

it works and a discussion/conclusion section. Each group will provide one common

report with an appendix indicating the contribution of each individual team member.

Submit your report before the due date.

Unprocessed barcode

Thresholded image

Resistors:

120 349Ω

1k, 2.2k, 4.7k

10k, 22k, 47k

100k 220k

2.2F* 4.7F*

10F* 22F* 47F*

100F*

Diode: 1N914 Red LED Green LED (long lead is LED anode, +ve)