Our project focused on giving normal home lighting intelligence the ability to give notifications about the status of a home. Using the Phillips Hue lighting platform, the team was able to deploy a system that would modify and return the state of a home’s lights to indicate someone was present at the front door. The internal module of this project was then able to signal the recipient at the door acknowledging their presence. The data collection and transmission was done via 802.15 Xbee radios that would transfer the initial signal and acknowledgement two ways.
This project was undertaken in order to develop a prototype which would utilize embedded systems and demonstrate elements of data collection and data transmission. Our inspiration came from the consideration that those suffering varying degrees of hearing loss do not have a full-home solution for notification of someone at their door. The traditional doorbell is an age-old method for notifying a resident of someone calling for their attention. While this has been an effective method for the most part, we saw potential to integrate today’s technology into a system that could provide a more advanced notification system, and be more effective for use for those with hearing loss than existing solutions. It also provides a base for further development with the potential to be built upon to increase its functionality and add features.
What does it do?
A sensor is placed at the front door to a residence that senses when someone comes to the door; sending a signal indoors to a listening and controlling component that flashes Philips Hue lights a couple times to alert the resident of the situation. The resident can press a button from inside the home that flashes another Hue light located by the door to signal the visitor the notification has been received, and the resident is coming to the door.
The door component consists of an Adafruit passive infrared sensor, an Arduino, and an XBee. The Arduino is powered by a USB cable plugged into a standard wall socket adapter. The PIR is then powered by the 5V output of the Arduino while the XBee is powered by the 3V output of the Arduino. The XBee is configured as an AT router and its transmit and receive pins are connected to the respective pins on the Arduino. The router is used to exchange serial communications between the two Arduinos in the system. The PIR sensor has a single analog output which is connected to the analog 0 pin on the Arduino. The sensor outputs a cone shaped field of infrared light. As long as there is no change in the field, the sensor sends its voltage out of its ground connection. When a change is detected, the sensor sends the voltage through its output pin to the Arduino. The Arduino reads this voltage as an analog value. The Arduino is programmed to respond when the value is above a threshold. This threshold was set just below the average value obtained from testing to compensate for variation. The Arduino responds to the sensor, by sending an ASCII character through the XBee to the component inside the house. Like the indoor component, the outdoor component is a standalone system. Additional sensors can be added and the Arduino can be programmed to both accommodate new sensors as well as receive commands from the other end to trigger additional attachments such as LEDs or motors. The system is limited by the voltage and amperage output of the Arduino. If too many additional components are added in series with the existing components, the voltage will drop and the XBee may not get enough power to function correctly. This may be somewhat mitigated by reversing the power sources from the Arduino and calculating the voltage draw resulting in powering multiple components in series so the XBee continues to receive exactly 3.3V.
This system is a step toward full smart home technology integration as it already integrates with an advanced home lighting solution and has the potential for even more. While the price of the system in its current state is relatively high, further optimization can make for a very enticing product for the tech-savvy as it is not limited to the original purpose of helping the hard-of-hearing. This project was an exploration of the very same goal Microsoft is working toward — the addition of technology into homes everywhere and to enhance the lives of residents using integrated systems. As technology develops, this trend should grow and soon homes could be looking very different from how they look now. The depiction of futuristic smart homes that has been, up until now, a mere figment of the imagination, is now closer to reality than ever.