Currently under active development,
the openSpectrometer is a scientfic-grade device
for separating and measuring the
UV and Visible frequencies of light.

• Toshiba TCD1304AP - 3648 pixel CCD array
• Processor - Parallax Propeller - 8 cores @ 96Mhz each
• 16-bit Analog to Digital Converter (ADC) - Wolfson WM8253
• USB 2.0 interface for streaming data and device configuration
• On-board SD card for data-logging
• Acquires up to 60 spectra per second

• Fiber coupled (looking at commodity TOSLINK for some applications)
• Concave holographic aberration-corrected grating (200nm through 800nm)
• Holographic transmission grating (VIS only)

• Desktop application written in the cross-platform Python scripting language
  • Runs on Windows, OSX, and most GNU/Linux distributions, hosted on gitHub

• Cuvette holder
• Dip probe
• Sample pedestal (for measuring small liquid volumes)
• Light sources
• Calibration kit

Technical Backgroud:

The openSpectrometer is designed with laboratory use in mind, but also focuses on being buildable, maintainable, repairable, and upgradeable.

The CCD is a high-sensitivity sensor used in many commercial spectrometers, along with a high-resolution 16-bit Analog to Digital Converter. The modern Parallax Propeller microcontroller boasts 8 independent processing cores, allowing it to easily orchestrate the glue logic between the CCD, ADC, USB, and microSD card.

Data can be obtained continuously and saved to disk, streamed via USB, or transferred to another device via GPIO (i.e. SPI, I2C, ethernet). You decide how you want to get data from it.

Utilizing multi-mode fiber optic cables eliminates the need for an entrance slit, the aperature is equivalent to the fiber core's diameter, and makes it easy to change between optical attachments like cuvette holders, dip probes, and pedestals for drop-size volumes. The concave grating eliminates the need for other mirrors or lenses in the optical path, simplifying assembly to just three items (Fiber port, concave grating, CCD).

Plans for everything will be freely available under open license, and kits and assembled devices will be fairly priced. By donating our design time, we are able to keep the price low. Providing the openSpectrometer in kit form will further decrease cost for those who are not afraid of solder and screwdrivers.

Project Background:

The device is primarily the work of Nathan McCorkle and Christopher Tomkins-Tinch, but is also the product of numerous DIYbio Google Group discussions. As bioengineers with hacker spirit we want to produce low-cost, high-value scientific instrumentation. We want to build a capable spectrometer that costs less than comparable commercial units, and is easier to use. It's our hope that an openSpectrometer is something anyone can find a use for, whether in the lab, home, classroom, or as part of another project.

All commercial spectrophotometers we've worked with have had horrible user interfaces. We were disgusted with how difficult it was to read and save data. Often these machines had a USB port, but couldn't save the current spectrum to a thumb drive! One of these devices included Tetris and Sudoku games, but not simple features to increase usability! We wanted to make it simpler to obtain data from these instruments, but because their firmware wasn't public we couldn't fix the bad software. The only options were to put up with the bad design, or build a whole new device based on hacker-friendly principles.

The desktop application will be designed with users and typical workflows in mind (e.g. pH colorimetric determination, DNA RNA and protein concentration). We would love if can tell us what matters to you, and how we can make reading data faster and easier. Head over to the forum to let us know:

http://www.openspectrometer.com/forum

Of course, it will also be open source. Mechanical drawings, electronic design files, and software source code will all be provided under open license. We're still working out which license we will release under, but it will be one that makes it easy to adapt the design for new applications.

Everything will be available on GitHub for download and community revision. Look there for mechanical drawings, electronic design files, software source code, bug tracking, and project documentation.

https://github.com/nmz787/open-spectrometer