Final Review

I believe our project was a success even though it failed to perform on the presentation day. We can prove the buggy’s performance via the video link in our blog (please see below). Hopefully this will be taken into consideration when allocation marks for the buggy performance. We discovered that the buggy showed good tracking skills by following the black line on the paper.
Conclusions of the buggy...
The Line Sensor should follow the presented design using visible light
The Chassis should follow the presented design except for allowing for other modifications
to the design.
The LDRs themselves were not of the best quality and because of their sensitivity we had to keep changing the values of the program.
On the improvement point, we could improve on the buggy’s programming. We could have programmed the buggy to reverse but as we concentrated too much on the design therefore we didn’t have enough time to do the final programming.

Overall the project was rewarding as most of the team members worked closely together to bring this project to a conclusion. (Adam Rana, Aftab Tahkur, Suraj Sohan and Harmandip Singh).Also I feel the buggy’s performance is now to a competitive level and can perform to meet the objectives.

Afy conclusion

all in all i think the buggy project was a success we did manage to get it to work however on the day, typical as it is it didn't work. the workload was split equally between the five of us, however the commitment started to dicipate. in the end we stuck our heads together and got it all done and finished. it was a shame that the buggy decided to blow itself up on the presenting day, we had tried everything in the morning to reprogram it and all sorts but never accomplished it. the group members gave all there interest and put forward their ideas' however stupid we all worked together. i think if we were to do this again it would be more structured so that if we were to run into a problem like this we would have more options to overcome it. i also believe we should have used another material because this made the buggy heavy n depreciated the power weight ratio.

Suraj Conclusion

I feel that the project was fairly successful, even though the robot didnt work correctly on the demonstration day. We made great progress and had the robot following the line. We have included a video of the robot following the line and then turning to the left. We then attempted to improve the robot so that it will also turn to the right, and then stop once it reached a solid line from left to right. In the process of doing this we hit a dead end. A problem occurred which made the robot completely useless. We believe that the microchip used had been damage in some way. We realised this after we had improved the coding and then attempted to reprogram the chip. However there is some light at the end of the tunnel. it was a great learing curve and i feel that if we had a replacement mirco chip we would have been able to reprogram it and have the robot working.

Last minute tinkering

On the testing day we ran into a few problems. The buggy stopped working completely. We were unsure of the problem so we had to investigate. Firstly we checked that the batteries were ok (they were fine). then we attempted to reprogram the chip as this may be the cause of the problem. This is were we had the problem. everytime we attempted to re program the chip an error message appered listing a number of possible causes. This made us think that we had a wiring problem, possibly a short circuit. We then checked all connections and we even used insulation tape to prevent any close wires from touching one another. The problem was not resolved and therefore lead us to believe that our chip had gone faulty.

The Working Buggy

just to clarify i did not push the buggy across the line i just helped it along like everyone else did

Program used for our buggy

Development of the Buggy

Build Stage

Here are some of the pictuers taken throughout the build stage of our project...

This is the final design of the buggy structure... also allowing the space for the circuit to be mounted on...

Build Stage

As some members of the team worked through the circuitry of the buggy, the designing of the buggy was also undertaken. We had to make sure that our buggy is strong and robust hence we had to take several ideas into consideration inputted by all members of the team.

The use of construction toys....

We used these construction materials as the final design can easily be altered if need as it would not be a permanent construction. The choices of toys were Lego, K'nex and Meccano.

We had to compare their advantages and disadvantages before choosing the correct material to use.

The use of nuts and bolts is a much more reliable method for the construction as it is interchangeable. It is also cheap enough to use. The use of meccano will also deliver a strong chassis for our buggy.

Chassis Development

Chassis Development

As a group we thought of many different ideas for the chassis, Then we narrowed down as we thought most of these ideas were not realistic for a number of reasons, such as rigidity and being difficult to build.
The size of the buggy was determined by the circuitry which is to go inside it. Once we had
got a basic idea of the electronics side of the project we could then start to construct the
chassis. This determined the positioning of the sensors, motors and the front skid. We
decided to position the line follower sensor in such a way to enable it to handle the tightest
corners.
The circuit boards are mounted to the chassis using meccano with nuts and bolts.

We decided to build our chassis with plywood which would have given us more liberty to change the chassis to fit the circuitry. Although, when the chassis idea was developed it looked very robust but it is not very adaptable in the final stages of the project. So therefore we changed our option of our chassis to meccano.

Using meccano to build the chassis is the most feasible and practical idea because it holds no limitations. If the design of the chssis needs to be changed at any point it can easily be done.

The Line Following Algorithm

A line following robot with three sensors only has a limited number of possible combinations. If the sensors are spaced such that only one sensor is normally over the line at one time, then the combinations are limited to the following....

000

100

010

001

111

In the reality these combinations will not be enough to allow for all situations.

011

110

101

The approach will be to assume the algorithm to be workable in the simplest form!

Components Required for our Buggy

• Picaxe 18x
• Darlington Drivers
• LDRs
• LEDs
• Wires
• Motors
• Switches
• Resistors
• AA batteries
• Buggy skeleton
• Bread board

Picaxe 18x

The PICAXE-18X is a four channel data logger; this microcontroller can be programmed to perform many different types of tasks. The data logger has 5 input pins 3 analogue or digital (labelled 0, 1, 2, on the left of the chip) and 2 which are strictly digital (labelled 6, 7 on the left of the chip). Whereas it has and 7 strictly digital output pins (labelled 0 – 7 on the right of the chip).

The data logger comes with a memory chip; this can store 2048 byte readings (8 blocks of 256 bytes). If you want to the memory capacity can be increased. For more data storage capacity the optional AXE111 memory expansion board can be used giving a total of 2MB of memory.

The data logger has been designed to run on 3xAA batteries or if using rechargeable batteries 4xAA should be used to run the data logger, both of which supply the microchip with bout 4.5 – 4.8 volts.


Pictured below is a layout of a picaxe 18x taken from our lectures notes provides by the lecturer.

circuitry

final stage the white wires on the darlington driver represent the motors
after this stage i extended the wires to reach the front of the buggy and connected the motors aswell.




Stage 2


stage 1

Type of sensors used on our buggy

In the circuit we are going to use a Light Dependent Resistor. LDRs are usually used in light or dark sensor circuits. When the LDR is in the dark it can have a resistance of mega ohms, when the LDR is in light its resistance falls to just a few hundred ohms. It also works in the opposite way depending on how the circuit is wired up and where the LDR is placed in the circuit.

In our circuit we have decided to use 3 LEDs and 3LDRs. The LEDs were placed in front of the LDRs to get maximum feedback from the LDRs. As shown in one of the previous post the more LEDs and LDRs you have the better the line robot will perform in its task.

In the circuit design we were considering to use 3 white LEDs. You could use more LEDs but the 4.5 volts form the 3 AA batteries would not be enough to power the LEDs thus they would run out too quickly. If the battery was changes to a 9v battery we could have up to 5 strands of 2 white LEDs in parallel in a circuit but the battery would only last up to 5 hours.

Thus in the end we reverted back to our original idea and used 3 red LEDs and 3 LDRs. The robot was wired up such that as the robot passed along the black line the LEDs would be on (emitting light). The light from the LEDs would get reflected back towards the LDRs from the white background. Where the light was getting absorbed (along the black line) no light would be reflect to the LDR thus giving a pathway for the robot follow.

Pictured below is an example of how the LED will emit the light and how the LDR will receive it.

motor config.

we had decided to place the motors at the rear and had luckily figured out how to stabilise them to run simultaneously

motor config.

we had decided to place the motors at the rear and had luckily figured out how to stabilise them to run simultaneously

Circuitry used in our buggy

before i forget the actual circuit that we had used.......

first stage

we had started designing the chassis

we had bought a simple meccano set and altered it to how we wanted it.

Existing Products

I have been looking at existing line robots to help give us some ideas of how to put the robot together. I have found that there is no set way and that a line robot can be made from almost anything. For example, I have shown below 2 robots. 1 which has been made from a sandwich box and the other from a wooden box.

Sandwich Box Robot - http://www.robotroom.com/Sandwich.jpg

Wooden box Robot - http://media.photobucket.com

After looking at these products it is now clear that there are a number of different ways we can construct the robot.

How does a follow the line robot work???

The line robot works by using a line of sensors to detect the line beneath it. As you can see from the pictures below, on the left it shows how the robot follows the line and on the right highlighted in red show the route that the robot actually takes.

As you can see the robot has a wave pattern route that it takes whilst following the line. Although we cannot make the robot follow the line directly, we can reduce the wave pattern by adding more sensors.

As you can see from the pictures above by adding a couple of more sensors the robot can detect the line better. As you can see from the picture on the right this thus reduces wave pattern route the robot takes, resulting in a smoother and shorter route that the robot has to take.

assignment

it was decided that by the end of this week,
harmandip: programme to follow commands
Aftab: design the circuit board
Suraj: what sensor to use. how to make the robot follow the line
Amardeep: research on the code
Adam: how to improve the reaction of the sensors
Camran: aesthetics of the robot

hello group

May Allah bless us with His merciful hand on this project.

Amardeep Singh Dhillon

Introduction

This blog will outline the design, construction and testing of our line following robot. It will show detailed sections on the design stage and how each individual’s tasks came together to
make the robot function.
The blog will stress the changes that we needed to make to achieve a functional product.

The aim of this module was to work as a group to design and construct a robot capable of
following a white line.
We will be working as a group, and thus should improve our skills of working together to
achieve goals.