Senior Design II paper
Download 0.59 Mb.
|
- Navigate this page:
- Infrared Emitter and Detector Requirements
- Triangulation
- Processors
- Graphical User Interface
- Relevant Technologies
- Remotes
Requirements
To optimize the customer’s audio experience within the sport restaurant, the quality of audio received, audio transmission range and comfort will be considered in selecting wireless headphones. Since a majority of people can hear within the 20-20000 Hz range, the group requires the headphones to produce a frequency bandwidth response within 5% of the human audio range to deliver good sound to the customer. The wireless headphones must have an audio transmission range of at least 100 feet, to allow customer mobility while still receiving excellent sound. The size and form of the headphones must be considered for customer comfort and mounting additional features. Over-ear headphones are required to block out surrounding noise while using a thick headband to support additional wireless headphone features. With this consideration the weight of the headphones must be less than 1 lb. The battery run time on the headphone is necessary efficiently last 12 hours, to support constant customer use during the hours of operation of the sport restaurant while requiring no more than 12 hours of charging time.
The infrared emitter and detector used for headphone-to-television communication must have coupled peak wavelength between 850-940 nm for optimum efficiency. For the IR detector, the project requires a view angle of about 120 degrees with a linear detection distance of at least 6m. The viewing angle to find an IR signal can increase in range by placing more than one detector side by side. As for the LED emitter, the larger the radiant intensity the further the IR signal can travel. These requirements will allow the user to lock in headphone-to-televisions identification throughout the restaurant. This information was compiled from [1] and [2].
The Triangulation module of the project has to do with being able to track multiple headsets in a given room. The idea is to be able to figure out where a person is sitting with respect to the headphones which will tell us who the user, is and if the headphones are still located in the room or bar. The triangulation needs to be done inside a building without the use of GPS. It will have to be able to track multiple moving headsets which will then be displayed in the Graphical User Interface in the mobile device. The triangulation needs to be able to calculate the exact (X, Y) coordinates of the headphone in a given room of dimensions (W, L) provided by the user or vendor. The triangulation needs to tell the difference from a movement of 1 meter minimum and a max movement of the size of the room itself. It should be able to work if there is interference in external objects moving around the room. The triangulation system should be able to calculate the position of multiple headphones as close to real time as possible while keeping the data processing to a minimum for low power consumption. The triangulation system needs to work in extreme conditions from temperatures of 50  - 100 . It should be able to work while tracking at least 20 headphones at the same time. The triangulation needs to work even if there are walls in between the detectors and the headphones. Overall the triangulation system needs to be reliable, low cost, low power consumption, high triangulation range, and have easy reprogramming options.
The group will be working with several sensors and wireless transmission, ranging from autonomous to a simple switch, so the group needs a reliable micro-processor. The module to use should be of low cost and reliable, it should be fast but have low power consumption, and it should be easy to program. The micro-processor should have an internal clock, a low voltage powering system, at least 3 serial ports, and at least 12 digital pins. It should have low noise for wireless communication, and it should be pin through, since it is of lower cost to populate the boards than having them populated. The micro-processor should have high RAM, multiple baud rates for serial write/read, and have a good and exact clock for dealing with transmission cycles. For the sports restaurant’s staff to monitor the location and status of their headphone investment, it would be beneficial to have a Graphical User Interface (GUI). This GUI must have the capability to render a map of the restaurant on a smaller scale and be easy-to-read; a screen size of 7 inches to 10 inches would suffice. The device running the interface must have access to a Bluetooth Stack and be able to send data to and from a Bluetooth module; preferably with at least Bluetooth Version 2.0. USB ports are necessary for any expansion or communication requirements (talking with other devices). The device also needs to have a high-end processor (preferably a dual-core processor) to quickly update the location map and communicate to the master microcontroller. The interface must be designed to be visually stimulating with buttons, text fields, dropdown menus and a drag-and-drop method. It must also take care of all high-end and complex requests from behind the scenes without the user being aware. This would allow the user to fully interact with the system without requiring too much technical knowledge. Location data must properly be displayed to within half foot accuracy.
Within the realm of technological advancements, past inventions and system protocols can be used in future designs as sub-systems to increase functionality of a multi-system project. Past technologies may even be enhanced for longevity, optimization, and functionality in new systems. This section will focus on discussing relevant technologies used in similar applications to the Eye Can Hear You project.
Remotes are used in applications ranging from switching channels on a television to controlling mobility options of remote control cars. Remotes pass control information from devices such as buttons or joint stick through a wireless communication to a receiving device to be processed. The commonly used wireless communication systems in remotes are infrared and radio frequency. Infrared communication is used in audio and video controls in most home theaters. The remote works by pressing a button that pulses the infrared LED of the remote at a particular pulse width modulation for a corresponding button. The LED pulsing represents a binary code. The infrared detector located at the source of the audio or video, receives the infrared pulses and decodes the signal into a digital value to be sent to the microprocessor [61].The microprocessor uses the digital inputs to control the electronic device’s operation [60]. Different remote control developers use different protocol to define an on bit and off bit for the IR LED and detector. The remote control protocol implementation in infrared communication is unlimited. Radio frequency communication is commonly used in car fobs and remote control toy cars. A radio frequency remote works by transmitting radio waves that correspond to a binary code for each button pressed [60]. The receiver decodes the radio waves and outputs a digital signal to the microprocessor to carry out the function received by the remote. Radio frequency communication in remote controls has a similar application to infrared communication due to transmitting a signal through a medium then receiving, decoding and actuating an operation. Both communications have possible interference due to obstruction in the line of sight of the infrared remote or other devices within range, transmitting radio waves on the same frequency as the RF remote. However the technology of the infrared remote implemented in the Eye Can Hear You project will allow wireless data transfer within line of sight. This technology will allow the project to identify which headphone is viewing a particular television by sending an infrared pulsing identification signal from the headphones to the television infrared detectors to decode.
|