Knock Knock, Who’s There?

Created on 26 Oct 2019

A knocking detection device that frees up your attention and helps the hearing impaired know someone’s at the door.

Our project will have two parts. There will be a device that adheres to the door and detects knocking. Once it detects knocking, a wirelessly connected robot will visually notify the homeowner that someone is at the door. The robot will help distinguish between strangers and friends by providing different visual cues to the homeowner. The homeowner can then decide how to respond to the visitor.


Sharon Chu


Yuqi Zhou


Halanna Yuh


Eleanor Pena

Part Cost Quantity Total
plywood $12.50 1 $12.50
wood for building the robot
HDMI 4 Pi: 5" Display (no Touch) w/Mini Driver - 800x480 HDMI $59.95 1 $59.95
For displaying transmitted images (on the side of rpi)
Raspberry Pi 3b $35.00 1 $35.00
For receiving images from the arduino's camera
battery pack $2.95 1 $2.95
battery pack for the LED light
LED Light Strips $16.00 1 $16.00
lights for the robot arm
Budget Pack for Metro 328 - with Assembled Metro ATmega328P $29.95 1 $29.95
For use with piezo. Includes wires
ARDUINO UNO R3 [A000066] $18.00 1 $18.00
For use with piezo
HC-06 Bluetooth Serial Pass-Through Module $8.99 1 $8.99
For transmission between rpi and arduino
CMOS Sensor Camera Module SCCB $10.99 1 $10.99
Camera for capturing person at door
Small Enclosed Piezo w/Wires $0.95 4 $3.80
To detect vibrations from knocking
Large Enclosed Piezo Element w/Wires $0.95 4 $3.80
To detect vibrations from knocking
Mini Pan-Tilt Kit - Assembled with Micro Servos $18.95 2 $37.90
For robot arms.
Project Totals: 19 $239.83
Track 1 Base Budget: $250.00
Preferred Vendor Budget Bonus: $0.00
Remaining Budget: $10.17
Sharon Chu 16 Jan 2020, 11:20 p.m. EST
Day 4: we’re done! Our robot now responds to knocks by shining in red and raising its arms! It also shows a live video of who is at the door. In the end, we weren’t able to implement wireless video sharing, but we successfully achieved the same thing with cables (which is not necessarily a bad thing, because hey, cables are stable).
Sharon Chu 15 Jan 2020, 10:50 p.m. EST
Day 2 & 3 progress: assembled robot arms and servos, servos panning and tilting correctly, robot can now wave at you :) We started working on the piezo knock detection and the bluetooth component of the project. We plan to have two piezos for knock detection, one that sends a signal to our LEDs (to light up interior of the robot), and another that sends a signal to our servos (to make the robot arms move). The bluetooth part of our project is looking pretty unpromising due to issues with installing Android on an rpi. We specifically need Android to enable wireless, real-time video sharing that can show our users who is at the door.
Sharon Chu 14 Jan 2020, 7:41 p.m. EST
Day 1 progress: cut out all parts, assembled robot's body, made pan-tilt kits (mostly) functional