The open source modular spectrophotometer
Di-Lambda is a fixed-wavelength spectrophotometer designed for colorimetric assays, used in biochemistry or environmental science.
Di-lambda is not just another lab tool: it is a modular spectrophotometer, which can be opened, reassembled and customized. It is a powerful tool for education in chemistry, physics and biology courses. This tool has been the result of a close work with teachers and school for over 4 years.
Authors
Alexey Zaytsev
Hardware design
Hardware documentation
Industrial production
Juanma Garcia
School workshops
Documentation
Science applications
Sonia Agüera
Workshop documentation
Institutional partners
CRI Paris
Funding for first test production
Hosting and equipment at CRI makerlab
Tsinghua graduate school in Shenzhen
Open F.I.E.S.T.A. program
Hosting in Shenzhen in 2016
Académie de Versailles
Science workshop and feedback
Teacher training
Doing It Together Science
EU project H2020. Funding for school workshops using di-lambda
Specification
| Absorption measuring range | 0A - 3A |
| Light path height | 8.5mm |
| Cuvette shaft | 12.5 mm × 12.5 mm |
| Spectral bandwidth | 10nm - 35nm (see list below) |
| Detector Type | Enhanced UV PIN Photodiode |
| Fixed wavelength (nm) | |
| Power consumption | 1W (5v, 200ma) |
| Power supply | Micro-USB (5V DC, 200ma max) |
| Interfaces | Micro-USB (to PC) |
| Weight w/o accessories | |
| Dimensions (W × D × H) |
Description
A spectrophotometer measures the amount of light that passes through the sample at a given wavelength. To produce light at the right wavelength, most spectrophotometers use a mechano-optical system to position a monochromator at the right angle from the light source, and a slit to only select the right wavelength. DIλ is an Open Hardware spectrophotometer, designed to be accurate, easy to modify, and extremely cheap. We achieve this by using LEDs instead of an optical refraction system.
This design choice means that the device is limited to one or a few pre-selected wavelengths, but most biological applications only use a few. It is also possible to select a different wavelength by populating a spare LED board, but since it's so cheap, it might be easier to just buy one for each task. Another disadvantage is large spectral width of LEDs, typically 15-25nm, compared to 1-5 nm for traditional spectrophotometers.
With a few wavelengths, the spectrophotometers allows anyone to make real experiments! You can measure the quantity of glucose in your drink, measure the pH in water, and much more. One of our early versions is still used by a start-up from Paris to quantify grown of the spirulina algae.All this means that DI-lambda is not always able to replace a traditional spectrophotometer, but works great for a majority of biological applications.
This machine is now being produced and sold by Koi Science, based in China. Check http://koi.science/downloads/ for software and contact Koi Science if you are interested in buying one!
Workshops
- SWIS workshop in IES Antonio Domínguez Ortiz in Sevilla, Spain (May 2018). Mentors: Juanma García and Sonia Agüera.
- Summer school CRI Paris, France (July 2018). Mentor: Juanma García.
- Science Fair at CRI Paris (September 2018). Mentors: Sonia Agüera, Joanna Zoell, Forum Shah.
- DITOS Final event at Brussels' Natural history museum (May 2019). Mentor: Juanma García.
- SWIS workshop in Liceul Tecnologic Pantelimon in Bucharest, Romania (June 2019). Mentors: Juanma García and Sonia Agüera.
- Sustainability summer school in CRI Paris, France (July 2019). Mentor: Juanma García.
Design files
Click on the links below to start downloading
↓ Github repository with design files
↓ Di-lambda report 2015 (accuracy of first version)
↓ Building guide paper version
Applications
Media
Other open hardware projects
For some time, we put some efforts to design and mass-produce open and low-cost laboratory equipment for schools, laboratories, DIY-Bio community, industry, Citizen Scientists, and everybody else. We try to do this without compromising on performance, by taking unconventional approaches, concentrating on just major use-cases for a given device, and staying true to our goal.
We welcome everybody to participate! All our hardware is open-source, you are free to build, modify and share it. We will also mass-produce the devices to make them available to all users at a low cost.
Criteria for our projects include:
- We need to be able to lower the price significantly, ideally an order of magnitude or more.
- We can make it work as well or nearly as well as existing devices, even if for a subset of applications.
- It's possible to mass-produce the device.
All our hardware projects are documented extensively in our wiki and github repositories. Click here to visit.