Citizen Science Badge

A badge that enables data collection using a microphone, BME688 air quality sensor to collect data, and upload it using a cellular module.

Badge in action

Some applications of the PCB include:

  • Automating Air Quality data logging using known sounds
  • Conducting community science experiments using a combination of sensors.
Components of the badge

The components of the badge are listed below according to their corresponding number along with their application. They are:

  • Invensense ICS-41350 MEMS Microphone. The audio captured from the microphone is used to detect sound using Edge Impulse
  • Raspberry Pi RP2040 microcontroller with 64MB flash.
  • Blues Wireless cellular module is used to upload data points to the cloud as well as receive “Save The Air” alerts from the cloud.
  • Automotive Gauge Stepper Motor (x27.168) – Used to indicate measured air quality index.
  • Bosch BMI270 IMU to detect motion
  • DA7280 for haptic feedback
  • BME688 air quality sensor to calculate air quality index as well as detect odors
  • JST/ Qwiic sensor port for connecting external sensors.
  • 3 x AA battery pack
  • USB C port for programming.

A detailed write-up is available from on Hackster.io

VOC sensors

I worked with Professor Eric Paulos at Carnegie Mellon University on this project. This is a wearable device that can measure concentration of atmospheric VOC (volatile organic compounds). These gadgets were meant for the Clean Air Initiative in Pittsburgh and funded by the Heinz foundation.

These gadgets were demonstrated by Professor Paulos at the White House Technology Office. The sensor is interfaced to a microcontroller and runs off a 9V battery. I designed the PCB and wrote the firmware for the gadet. The video below shows its function.

Boxing datalogger

I designed this board for a friend. It collects data from a pressure sensor and an accelerometer, transmits the data through a bluetooth module (bluetooth serial module). The board is powered using a Li-Po battery and embedded inside the boxing glove. 

 

Carbon Dioxide Monitor

I built this carbon dioxide monitor at my first job (Picture taken with permission). This was my very first PCB design. It makes use of a PIC16F877A microcontroller. The sensor is interfaced to the microcontroller via the I²C interface. It also controls a 16×2 LCD display. 

The microcontroller triggers the buzzer when it crosses the threshold of 800 ppm. The unit had push buttons to adjust the trigger threshold. I also wrote the firmware for this unit.