Overview
A custom PCB designed to integerate with a TOF distance sensor and a Raspberry Pi Pico sending doorway Entry/Exit events to AWS IoT. Designed to be compact and deployable in Seniors' homes.
Technologies Used
- CAD: KiCAD, Fusion360
- Programming: MicroPython, Thonny, MQTT, AWS IoT
- Electronics: Raspberry Pi Pico, TOF
Key Features
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Accurate Entry and Exit Events
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Robust Wireless Communcation
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Power and Network Error Failsafes
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Status LEDs
Contributions
I worked on designing, prototyping, and assembling these PCBs. The circuit had to be compact and fit in an enclosure that could be mounted on a doorway. A lot of time was spent programming the Pico — while entry and exit events appear to be simple, there is lots of signal processing and internal data management needed for quality assurance.
Additionally, as these devices initially interfaced with other bluetooth sensors, I had to modify the firmware of the pico to allow it to connect to many bluetooth devices (which, at the time, felt very cool).
Challenges
Making these devices easy to set up upon disconnect and immune to failure when tampered with was very difficult. It formed many wireless connections, which required lots of logic to catch errors and notice spotty connections. Data was stored locally until it was confirmed that the events were properly recieved by an AWS databse. Wireless connections were consistely restored while the sensor was still reading.
Developed at my first summer @ Synclabs, starting June 2024
Other Photos
A batch of sensors being tested!
Sensors mounted on door to track entry/exit into lab