307CR Coursework 2: Group ReportBy: Nikola Dafinski 7297209

and Daniel Rizhkov 7118890Introduction

Our group decided to go for a RFID scanner which stands for Radio Frequency Identification. It is a very popular pervasive system nowadays and helps identify items or people by simply

scanning a barcode or a card. It normally involves at least two objects – something that transmits – such as an RFID tag, and something that receives – a reader or interrogator. The

way that works is normally readers have an anthena(not necessarily a visible one in the modern age) that sends or emits a signal which contains a field of elerctromagnetic waves which are then received by the chip. That charges the transmitter enough to send a signal back to the interrogator with the ID number. From there, if the ID number is valid or in the

system, access is either granted or denied.

Aims and objectivesThe aim of the project is to use an RFID scanner and with the use of a few different tags

make an accurate enough system that responds correctly to each of them. Our main goal is to have at least two tags – one in the database, the other not, or in a denied access

database. Scanning one or the other will in turn result in the RFID sending a signal to one of the two lights – red or green – red for denied, green – granted. It will be tested on items with chips that are not tags, for example credit cards or student ID cards, to make sure it

does not malfunction.

ResearchFirst of all we started by researching more about RFID scanners and how they work. Once

we were confident enough that we have the needed knowledge started looking at the types of RFID systems. We found out that there are quite a few types based on different things.

For example based on frequency, which is the size of the radio that is used to communicate between all parts of the system, there are a low frequency or LF, high frequency or HF and

ultra-high frequency UHF bands. As we found out there are a lot of differences between them. For example RFID systems with lower frequencies are slower, but they do not get

influences by metals or liquid surfaces, on the other hand, if you have an RFID with a higher frequency it will be much faster, but there is the con of it getting affected relatively easier by outside elements. To get an idea what the different frequencies are for example LF are from

30 KHz to 300 KHz. Then HF are from 3 to 30 MHz. UHF are between 300 MHz and 3GHz.

Based on activity they are passive active and BAP RFID systems. In active systems there are particular transmitters and own power sources. In most cases the source is a battery. They normally work on UHF. In passive systems the reader antenna sends a radio signal to the

chip. Then the chip uses the signal to reflect its ID back to the reader. They work on all frequencies, but are normally under 10m. Battery assisted passive systems are consisting of a inactive tag that joins a urgent active tag highlight. They use a coordinated power source

to control the microchip, so most of the information from the reader can be used for backscatter. Unlike transponders, BAP tags don’t have their own transmitters.

System Design and DevelopmentFor our own RFID system we decided to use Arduino. That is a open source electronic

platform based on very simple and user friendly hardware and software. It was used as an easy tool for fast prototyping, aimed for students without any idea about electronics and

programming. When it became popular and available on a lot of places, it started adapting to changes. Arduino is inexpensive, has a simple and clear programming environment, it is

open source and another perk is that it is cross platform. The microcontroller we are using is Arduino UNO. It has 14 digital pins and 6 analog pins. We decided to go for that, because we

had used Raspberry Pi before for a project, and had some difficulties setting it up. We connected our Arduino with our RFID scanner and then to the PC based on this schematic.

After that we looked up and found an Arduino library for the sensor. It included an example code which we used for making our pervasive system work. When you approximate a card or in this case a tag to the reader it shows your all of the information about it which is 1024

bytes divided in 16 blocks:

Each tag also has a unique ID which is in hexadecimal. Because we had two tags we wrote down the IDs of both of them and in the code using if statements made it so it recognizes

one of them and grants access but denies the other one.

This is the Arduino UI with the code and the serial monitor where the communication with the user happens.

This is the output when we approximate both of the tags to the reader. If you have anything more than two tags of course if statements in the code wouldn’t really be a viable option. In

that case you definitely would need a database to manage all the tags, such as SQL where you can store the students’ name, IDs and the IDs of their tags. New entries would have to be added in manually, though and if you also want to have different people with different

levels of access to a building you can have another database with the rooms in the building and everyone that has access to each. Another way this could be done is with a NoSQL

approach, where adding new tags and changing access privileges could be easier.

ConclusionIn conclusion we were very excited to work with electronics and programming again. Some

of us had previous experience with it and it was good to build on top of it. It was very interesting to learn something new, and that is why we chose that subject in the first place. Finding out more about pervasive systems such as RFID and others might push us to work in that area one day. It is very fascinating to learn how everyday systems, that we do not even see as such, work, and to understand how and why they are built like this. We believe that

what we learned from this group project will stay in our heads for long and might benefit us in the future. Our teamwork benefited greatly from this coursework and because we were

only two, we managed to work well together and to keep our deadlines, and most importantly our ideas and vision the same.

References:

https://create.arduino.cc/projecthub/Aritro/security-access-using-rfid-reader-f7c746?fbclid=IwAR2Hg4pVFCF1P3t6fv0_fL9plVEFpe6K-

SReEVOOp68Di7ePNkWcgOdi8Po

http://www.batlgroup.net/the-different-types-of-rfid-systems/