Starting in September 2014 I began doing problems in a college organic chemistry textbook that had an extended treatment of spectrometry. Fundamentals of Analytical Chemistry, 7th edition, Skoog, West, Holler, 1997.
I did experiments with reflective and transmissive diffraction gratings. I researched the Internet for examples of spectrometer projects.
A particular question that I have not seen writing about is why can't I point a spectrometer at the sun and directly graph the CO2 absorption taking place on the air column from my location to the top of the atmosphere? If a jet plane flies near the air column, can I see increased absorption taking place due to the water vapor and CO2 being released by the plane?
I am not done building instruments, but due to my need for a quantitative CO2 measuring instrument I purchased a commercial CO2 meter.
I purchased an atmospheric CO2 meter over the Internet from an organization aptly doing business as CO2meters.com.
The AZ-0001 CO2 meter has a rated accuracy of 50 parts per million. It is sold as an instrument for measuring indoor air quality. Closed buildings like skyscrapers typically turn on fresh air circulation fans when the CO2 concentration is over 500 parts per million (ppm).
The CO2 meter has a digital output for CO2 data. I decided to combine the CO2 meter digital data with location information from a global positioning receiver (gps) and further add barometeric pressure and a second temperature value from a microbarometer. For recording the data, I used a device called a SD Card writer which also has a battery backed real time clock similar to the device used in many personal computers. Reading and writing all of this data requires a fairly fast microcontroller with quite a few input and output connections. An Arduino Due is a really good choice for this mapper device.
Major components list:
- Arduino Due single board microcontroller.
- CO2 Meters.com AZ-0001 CO2 meter with temperature and dewpoint.
- AdaFruit.com SD Card Logger with Real Time Clock
- Adafruit Assembled Data Logging shield for Arduino ID: 1141 - $19.95 : Adafruit Industries, Unique & fun DIY electronics and kits
- AdaFruit.com microbarometer breakout board.
- BMP085 Barometric Pressure/Temperature/Altitude Sensor- 5V ready
- Alternate MPL115A2 - I2C Barometric Pressure/Temperature Sensor
- AdaFruit.com global positioning system breakout board
Power for mapper supplied by:
- 9 volt wall wart (for major logger) and 6 volt wall wart (for CO2 meter)
- AA Lithium battery pack with 8 cells for main logger and 4 more AA batteries to power the CO2 meter.
The software currently in use is the result of four months amateur part time development.
A recent working copy of the software is at the following link. The development platform for loading the software into the Ardino Due is downloadable from arduino.cc. Take note that the development package you download does program Arduino Due devices.
The software requires some drivers that are either present in the Arduino development environment or are available from Adafruit.com . Contact the author if you can not find them.