The Project
For this project, we were awarded the 3rd prize in Innovatron’18, an inter-college project presentation competition held at Sardar Patel Institute of Technology, Mumbai.
Problem Definition
During our internship at Fractal Analytics, we (Srijal and Me) observed a problem that the employees faced; being an open office, there were several meeting rooms on each floor which could be booked on a smartphone app.
Employees require frequent access to these meeting rooms, but a lack of real-time knowledge of its availability leads to inconvenience.
The problem was that anyone could book a meeting room and then not use it. Or if someone wanted to have a meeting without booking the meeting room he/she would have to go from room to room to check the availability of the rooms. This would create a lot of unnecessary hassle and would lead to non-optimal utilization of the workspace.
Solution Design
The idea was to create a network of sensors placed in each room which could indicate in real-time whether the specified room is occupied or not.
The solution design is as follows:
- We used a PIR sensor to detect occupancy of the room
- The sensor is connected to an Atmel microcontroller which relays the information to a central device via radio modules configured in a tree configuration
- The central device is connected to a PC and it will push the data to the internet via a python script running on the PC
- All the devices are battery powered
- To reduce the power consumption, we used a low dropout voltage, low quiescent current voltage regulator. This improved the quiescent current to 20uA compared to 5mA used by a standard voltage regulator like an LM1117. Also, the dropout voltage improved to 200mV from a typical 2v
Conclusion
The designed prototype has a polished look with a 3D printed case and the small form factor PCB. The PCB was designed to utilize small SMD components to achieve this. All the files and source code can be found at Room Occupancy Indicating Network on GitHub