In the course of Pervasive Computing we chose to develop a system that would allow opening / closing of door locks using a Web / Mobile based interface. The proposed system would not only allow one to operate door locks but based on these lock signals it would operate the room lights as well. The system would auto-lock the door and turn off the lights in absence of people in the room / lab.
The components used in the project were :
The components used in the project were :
- Software
- Django
- Android App
- GPIO control scripts
- Hardware
- Raspberry Pi
- Breadboard, Jumper cables, LED lights
- WiFi module
- Pressure sensor ( custom build )
Proposed System
The proposed system was for a specific type of door locks that existed in the labs of the institute. The door would lock / unlock on rotating the door knob clockwise / anti-clockwise. The design proposed was to mount a mechanical assembly over the existing door knob that would rotate the knob in appropriate directions. The assembly would typically contain a stepper motor and few joints to transfer the motion to the knob.
The assembly over the knob would also contain a compute unit that would be responsible for communicating with the central web server.
The assembly on the door knob would posses a small controller having wireless networking capabilities that would maintain the state of the lock and change the state of the lock by receiving commands over the network. The interesting part of the project was to identify the absence of people in the room in order to close / lock the door.
A custom pressure sensor was required to be placed on each chair in the lab. The presence of people was indicated by a person being seated in at least in one chair. The custom sensor was inspired by a colleague Siddhant. The sensor was a electrical circuit which was activated when contact was made between two points, separated by a sponge ring.
The limitations of this was that, no appropriate duration threshold could be determined to turn off the lights after the lab empty is determined using pressure sensors.
Alternative was to use camera recordings of the lab periodically, subtract the two images to find out if there is any movement happening in the lab to determine the presence of a person. This was achieved by using image processing library - opencv.
A custom pressure sensor was required to be placed on each chair in the lab. The presence of people was indicated by a person being seated in at least in one chair. The custom sensor was inspired by a colleague Siddhant. The sensor was a electrical circuit which was activated when contact was made between two points, separated by a sponge ring.
The limitations of this was that, no appropriate duration threshold could be determined to turn off the lights after the lab empty is determined using pressure sensors.
Alternative was to use camera recordings of the lab periodically, subtract the two images to find out if there is any movement happening in the lab to determine the presence of a person. This was achieved by using image processing library - opencv.
The project partner with whom I worked was Ajinkya Rajput from Computer Science branch. In the very beginning we had a nice bonding which faded over the period of time. The main reason was the inferiority complex that I developed because of having less interest in getting back to academics.
The project was extremely similar to Lockitron, a funded kickstarter project.
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