Innovation in Smart Home Technology

         There are numerous ways a smoke detector can be designed, from the different sensor types to the circuitry that holds them together. The two most widely used smoke detection systems use either a Photoelectric or an Ionization sensor. While Ionization sensors work based on heat, Photoelectric sensors trigger based on smoke. Through our research we have decided to use solely a Photoelectric chamber to sense the presence of smoke. Although that is technically the only sensor needed in order to build a functional smoke detector, our design takes if further. Since we are not implementing an Ionization sensor, we decided to take a different approach through the addition of an Infrared Temperature Sensor. The benefits of an IR temperature sensor are that they offer a non-contact measurement of the temperature throughout a room. Since statistically, fires are more likely to start towards the floor, we hope this sensor will be able to pick up a potential hazard even before smoke is present. Lastly we are including a Carbon monoxide detector. These are a necessary part to any home safety detection system as CO is a highly toxic gas that only sensors can detect due to its colorless, odorless, and tasteless nature. 

 

 Antenna

 

  Our antenna is a printed microstrip antenna utilizing a zero-order resonator to produce an omni-directional radiation pattern. The design incorporates loaded arms surrounding the patch which increase the current path in order to tune the resonator and decrease the size of the antenna. Our design was inspired from a similar publication, however was conditioned to yield a smaller design and operational frequency. Using CST Microwave Studio, a design was created, simulated and optimized for our desired operational frequency of 2.44GHz, which is in the center of the FCC allocated ISM frequency band used for WiFi. We then took these dimensions to fabricate, measure and characterize a prototype. It was found that the design simulates at a higher frequency than the fabricated device. Because of this, we were required to iteratively fabricate prototypes until the optimized operating frequency was achieved. In conclusion, we obtained the desired 2.42GHz operational frequency with a low profile microstrip antenna having a radiation pattern similar to a monopole. The following section covers the antenna in a publication prepared for IEEE. 

 

 

 

Board Design

Our PCB design incorporates both through hole and surface mount components routed on a single-sided two layer board. The size of the board was greatly increased due to prototyping practices such as using easier to install packages, jumpers and intervening circuit capabilities. With an updated design, both cost and size can be greatly reduced.

 

 

 

         Since our very first envisioning of WIRD, we imagined a device in which a smart hazard detection system could be seamlessly integrated with a WiFi repeater. This was accomplished through the use of a core hardware system that houses the software and process algorithms that allow our system to manage both of these technologies simultaneously. This is manifested in our Smart Alert system which takes advantage of the WiFi repeater’s internet connectivity to communicate with WIRD’s cloud based server which hosts the email and SMS alert protocols. While both the WiFi repeater system and the Smart Alert system share hardware, the individual processes are better explained as 3 subsystems which synergize to provide a seamless end-user experience. These subsystems are: The WiFi repeater, the data reading and parsing algorithms, and the Smart Alert system.

 

Our prototype device uses a Beaglebone Black in combination with a WL1835MOD attachment for its wireless system control.