Modular Environmental Monitoring Sensors (MEMS)

Early last month, the NM Climate Center team built and a Modular Environmental Monitoring Sensor (MEMS) package, which was tested at the 2014 Albuquerque Balloon Fiesta.  The purpose of building and testing the MEMS is to demonstrate our ability to gather data using inexpensive equipment. The hardware was chosen for its low cost and power.

MEMS system parts and functions:

Raspberry Pi – Read data from the Arduino Uno and Dylos.

Arduino Uno Micro Controller – Programmed to read pressure and GPS data from a pressure sensor and a GPS module.  It is connected to the Rasberry Pi via USB.

Dylos Air Quality Monitor - Counts large and small particle sizes and stores the average of both sizes over a minute.  Connected to the Raspberry Pi via Serial-to-USB adapter.

12V Rechargeable Battery - Provides the power to all the components of the system.

 

 

 

Photo 1: MEMS system and parts. By: Cristina González

 

 

An Arduino Uno was used to collect GPS and pressure sensor data.  A Raspberry Pi was used to log data from the Arduino serial console; the GPS messages and our own custom data message format for the pressure sensor. In addition to logging data from the Arduino, the Raspberry Pi logged data from the Dylos air quality monitor. A start-up script was created for the Raspberry Pi to trigger data logging on start-up.

The Raspberry Pi, running the Raspbian OS, booted into a standard terminal mode. During the boot process, an init script would start the data collection process from the Arduino and the Dylos serial ports. This data was then stored in an incrementing file name, to prevent overwriting files, over each on-off power cycle. In addition, a one minute file-write timer was built into the logging software to ensure that data was written on a continuous basis, since the sensor package was turned off by having its power removed.

The Raspberry Pi, Arduino Uno, and all power hardware is stored in a Rubbermaid container that is placed inside an inexpensive backpack.  The Dylos is attached to the outside of the backpack to be exposed to the ambient air.

After completing the build process, the MEMS was tested on October 11, 2014 at the Ballon Fiesta (photo 6). It collected data successfully and it will be available soon in the NM Climate Center website.

Photo 2: Building a bracket to hold the Dylos air quality monitor . The bracket is used to securely hold the Dylos to the backpack.  The Dylos had to be exposed to the air outside of the backpack.   Photo by: Stanley Engle

 

Photo 3: Attaching it to the backpack for trial. Photo by: Stanley Engle

 

Photo 4: Testing it at NMSU. It was left outside for an hour. Photo by: Stanley Engle

Photo 5: Data logger inside the backpack. Photo by: Stanley Engle

Photo 6: Testing the sensor hardware at the Balloon Fiesta. Photo by D. DuBois

Photo 7: Testing the sensor hardware at the Balloon Fiesta. Photo by D. DuBois