Dormbell

Inspiration

Our team always get knocks on our residence doors and we can't hear it because we are typically wearing headphones in our room. To resolve this issue, we created a wireless doorbell made for dorm rooms that give us an audible and visual notification when someone is at our door.

What it does

A person will press the doorbell outside the room and it will tell the receiver in the room that button has been pressed. The receiver (which is built in to the clock/timer) will provide the user with a audible and visual notification. In addition, an ultrasonic sensor built into the doorbell unit will detect if objects are in front of the door for prolonged periods of time and will visually notify the user about the potential eavesdropper.

How we built it

We used two ESP32 microcontrollers connecting over wireless Bluetooth connection to eachother to send data from the doorbell to the receiver. The doorbell consists of a standard push button, and an ultrasonic sensor that is constantly measuring for objects within a 1m distance of it. The receiver uses a 7 segment display to show the time, a buzzer to play the doorbell chime, and an LED light for the visual cue. The LED strip will start displaying flashing lights to visually notify the user when the doorbell is pressed. Simultaneously, the receiver will begin playing audio through a buzzer.

Challenges we ran into

We quickly realized the ultrasonic sensor, likely due to its cheapness, would randomly output distances of zero when an object was in front of it. This caused our measurements to reset when trying to calculate how long someone was in front of the door. To combat this, we changed the code so that it measured data the same way, but determined the time someone is at the door by an average of multiple measurements constantly being updated one measurement at a time. This would make it so a zero would not fully reset the measurement.

Another challenge was the 8x8 LED dot matrix, as it was very difficult to use with the little ports available on the ESP32. To combat this, we changed our display device to a 7 segment number display. Though we missed out on the aesthetically pleasing design of the 8x8 LED, we got to maintain the functionality of the clock and were able to stay using the ESP32.

Accomplishments that we're proud of

Successfully making a wireless connection between the ESP32's and being able to communicate data through them.

Creating the functioning the clock by catching data from through connecting to a wifi and using the clock from there.

Resolving the issue of the ultrasonic sensor making inaccurate measurements.

What we learned

How to use ESP32 microcontrollers (wired and wirelessly) How to play sound through buzzers How to make functioning buttons and assigning them to variables How to use the 7 segment LED display How to grab data from a

What's next for Dormbell

In the future we plan to integrate our system into a mobile app that will notify users on their phone when the doorbell is pressed as an added layer or notification. We also want to add one or two-way communication through the use of microphones so that the user does not even have to open the door to get information from the person if it is only verbal. Finally, we would like to increase the size of the clock and make it aesthetically pleasing.

Built With

• arduinoide
• c++
• esp32