RFA of Project **'The Hawk Eye Key Finder'**

# Problem:
Imagine a scenario when you are about to leave the dorm but cannot find the keys. You search everywhere in your dorm but still cannot find it and feel really frustrated. Because the size of the keys are usually small and thus can fit into places like under a sofa or bed which make it nearly impossible to find.

# Solution Overview:

The solution we come up with harnesses wireless communication technology. We will attach a battery-free passive RFID to the key to be found. We will place several stationary transmitter towers for tracking purpose. The user will hold a receiver. The receiver's location can be triangulated by those transmitter towers. The receiver will also fetch the relative distance and angle from the RFID to guide the users to their lost item. The user can read all those information from the screen installed in the receiver as well as LED to congratuate them approaching near to their lost items.

# Solution Components
## RF Subsystem
1. 5 or more transmitters to triangulate the receiver. We plan to use CC1101 as the core transmitter IC chip and several 433 Mhz +2 dBi antenna for both tranceivers.
2. One receiver in the user's hand to figure out the current location to those 5 Txs. We will also include a small size screen for relative distance indication. We will design the receiver by our own to achieve higher circuit performance.
3. Off-the-Shelf RFID to track the key or anything to be found. We are considering to buy FUJITSU WT-A522L UHF RFID Fashion tag.

## Power Unit
1. We will power the transmitters and receivers using DC battery. The passive RFID will be battery-free devices.

## Processing Subsystem
1. After the Rx collects the signal strength information sent from the Txs, we will feed those information to the signal processing chip or through TCP connection to a server to figure out the location by virtue of the triangulation algorithm.
2. The screen will show information processed.
## Software and Server
1. If many RFIDs are to be tracked down in a given area, we need to fetch information from it and figure out what the item the RFID corresponds to. Thus the software solution involves a database server and TCP connection to the receiver.

# Block Diagram
1. https://drive.google.com/file/d/1AXPhECZHLd_ruMx_-9gUrkk-hpi02mxJ/view?usp=sharing

# Criterion for success
1. The Receiver can measure the signal strength information and can be triangulated. (Since the wave frequency we will transmit is around 300-500 MHz, the wavelength is 1 m. We would expect the precision of triangulation to be within 30 cm and above 80% reliability. The error can be lowered if we incorporate certain algorithm such as the Ellipse localization algorithm.)
2. The stationary RFID can be tracked by the receiver. In reality, the lost key will unlikely to be moving and it is difficult to do real time location tracking to passive RFIDs.
3. The receiver know the location and the relative distance as well as the angle from the key.
4. The screen on the receiver can indicate the information above.
5. When the user reaches proximity of the key, turn on the LED light.

# Ethics and Safety
1. If psssive RDIF tags are attached to keys, phones or other important items, they might be tracked down by bad people like thieves and robbers.
2. TX in 300-500 Mhz with high enough power might be illegal under certain regulations.

# Competitors
1. Tile
2. SPREO
# Reference:
1. http://www.ti.com/lit/ds/symlink/cc1101.pdf
2. https://www.atlasrfidstore.com/fujitsu-wt-a522l-uhf-rfid-fashion-tag/?gclid=CjwKCAjwrNjcBRA3EiwAIIOvq-3_rrbimIS6sujUPfYrHmSN0ZQmNHo5TgGsY2PKcsh9mZ4Ug2truBoC-zQQAvD_BwE