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This project details an '''open-source colorimeter'''. This is part of a larger project to reduce the cost of scientific equipment using [[open-source hardware]]. Read more: Pearce, Joshua M. 2012. “[http://www.sciencemag.org/content/337/6100/1303.summary Building Research Equipment with Free, Open-Source Hardware.]” ''Science'' '''337''' (6100): 1303–1304. [http://mtu.academia.edu/JoshuaPearce/Papers/1935580/Building_Research_Equipment_with_Free_Open-Source_Hardware open access click through]
This project details an '''open-source colorimeter'''. This is part of a larger project to reduce the cost of scientific equipment using [[open-source hardware]]. Read more: Pearce, Joshua M. 2012. “[http://www.sciencemag.org/content/337/6100/1303.summary Building Research Equipment with Free, Open-Source Hardware.]” ''Science'' '''337''' (6100): 1303–1304. [http://mtu.academia.edu/JoshuaPearce/Papers/1935580/Building_Research_Equipment_with_Free_Open-Source_Hardware]


==Introduction==
==Introduction==

Revision as of 22:03, 30 January 2013

This project details an open-source colorimeter. This is part of a larger project to reduce the cost of scientific equipment using open-source hardware. Read more: Pearce, Joshua M. 2012. “Building Research Equipment with Free, Open-Source Hardware.Science 337 (6100): 1303–1304. [1]

Introduction

The STLs will build a case for a colorimeter and the electronics BOM will yield a device designed for performing high range Chemical Oxygen Demand (COD) determination, measuring absorbance at 606 nm, an absorbance peak for the chromic ion. The cuvette holder is designed for Hach COD digestion vials.

The light source was specifically chosen for chromic ion determination; it can be altered to measure other ions (aquarist: think nitrates, ammonia and pH). We're working on other designs and useful applications and invite you to join us and share your designs.

Colorimeters are exceptionally handy items used for determining the concentration of dissolved species typically in aqueous solutions. The principles of operation are simple and form the backbone of several other analytic methods.

Design files: http://www.thingiverse.com/thing:45443

BOM:

Instructions

  1. Print the parts and clean them up so everything fits together nicely. Push M3 nuts into their appropriate slots at each corner of the case body - slots open to interior.
  2. Cut the proto board down to size (about 27mm x 46mm) and drill holes to match those in the sides of the case.
  3. Loosely attach the boards to the interior of the case with a couple screws each and push the cuvette holder into place (no cover) and mark the approximate locations where the sensor and LED must be placed on the boards to align with the windows in the cuvette holder.
  4. Remove the boards from the case and solder the components to their respective boards at the points marked. Leave the LED leads a bit long so it can be moved to aim the beam through the hole.
  5. Solder the conductors per the schematic. (The io pins can be soldered to directly on the LCD shield if you're careful, otherwise different means will be required, like not using the shield as a shield.)
  6. Fit the boards back into the case, this time firmly.
  7. Download and install the firmware on the Arduino.
  8. Fit the LCD shield and power the device (surplus wall wart of appropriate voltage or USB power will work).
  9. Place the cuvette holder back into position (no cover) and use the menu system to select "Calibrate". The LED will illuminate for a few seconds - make sure that the majority of light passes as straight as possible through the cuvette holder windows and impinges upon the sensor. If the LED/sensor are high or low, reshape the cuvette windows with a small rat tail file or suitably sized drill bit.
  10. After the LED is properly aimed, remove the cuvette holder and align and affix the cover to the case with four M3 screws and washers.
  11. Push the cuvette holder through the opening in the cover and check that the lid fits nicely into recess.
  12. Follow the appropriate protocol for calibration (yet to be built into the firmware - forthcoming).


Applications

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