Raspberry Pi based kit tests liquid food quality

Raspberry Pi based kit tests liquid food quality

Sep 15, 2021 — by Eric Brown

— 155 views

An open-spec, RPi 3A+ based “π-LAB” device on Kickstarter is equipped with a spectrometer, laser, 5MP camera, and touchscreen, and is designed to measure the quality of liquids such as olive oil.

In Greece, as in much of the Mediterranean, debates about the quality of olive oil are taken seriously. To help settle such disputes and expand scientific inquiry to the masses, a photonics scientist named Georgios Violakis from the city of Heraklion on the olive-soaked island of Crete has gone to Kickstarter to launch a liquid analysis pocket lab called π-LAB (Pi-LAB).

Powered by a Raspberry Pi Model 3A+, the open hardware/software device includes a spectrometer, laser, camera, and other components to measure and analyze liquids. It will ship with a database and AI-enhanced software optimized for testing olive oil quality but can also be used to analyze any other liquid, including coffee, honey, and wine.

π-LAB and detail view
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The π-LAB is designed for hobbyists and teachers who want to explore food quality, computer vision, or the fundamentals of spectroscopy and lasers. It can also be used by professional food testing operations for low-cost intermediate screening.

The early bird Kickstarter package, which is due to ship in Jan. 2022, sells for 339 Euros ($401) and adds a single optical glass cuvette and a USB cable to the RPi 3A+ equipped system. The standard €379 ($448) package, which like the other packages ships in Feb. 2022, has the same basic accessories.

π-LAB with cuvettes
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A €489 ($578) Extended package gives you 10x cuvettes and adds a mini wireless keyboard, carrying case, and a crafted olive wood gift such as a pen. Other packages include a pricier Certified model that adds to that mix with a calibration certificate. The certificate confirms that all instruments have been pre-calibrated to show the kit is “guaranteed to work with a device-to-device reproducibility better (smaller) than 1%, assuring the highest level of accuracy in detection,” says the KS page.

The π-LAB “is by no means a substitute of high performance analytical equipment costing tens or hundreds of thousands of dollars (Raman / FTIR spectroscopy, NMR, PCR, etc…),” says the campaign page. “The idea is the combination of several analytical techniques and smart post-processing to outweigh the lack of resolution inherent to low-cost equipment, in order to determine the quality of liquid foods with the best possible accuracy.”

The kit integrates a 1.4GHz, quad-core, Cortex-A53 based Raspberry Pi 3A+, which was likely chosen for its small, 65 x 56mm footprint and because unlike the RPi 4 or RPi CM4, for example, you can easily find it in volume at the regular price. This $25, reduced feature version of the RPI 3B+ is equipped with a WiFi/BT module and 512MB RAM.

The π-LAB features a “novel” optical-filter-on-CMOS spectrometer with 8x visible channels and 1x NIR. The device works together with both laser and broadband white light LED sources, as well as custom software, to perform absorption, fluorescence, and computer vision analyses of liquids.

The π-LAB also provides a 5-megapixel camera with a macro lens for high magnification sample viewing plus “custom driving electronics.” A 5-inch touchscreen is also part of the package.

The kit ships with an SD card containing a Linux distribution with the entire π-LAB software stack and olive oil database. The open source software provides full control of spectrometer operational parameters such as integration time and sensor gain, as well as controls for acquiring images under LED and laser illumination.

π-LAB screenshots
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Out of the box, the device allows you to measure olive oil quality “with just a press of a button” and perform manual observations on the touchscreen. You can then compare the results with other olive oil samples in the database or other samples you have added.

The software can classify olive oil category in three categories and can detect if an olive oil has been adulterated. The olive oil market is plagued by food fraud, with some estimates claiming that up to 70 percent of all commercial olive oil has been adulterated, diluted, or falsely marketed, or is sold rotten or rancid. The project plans to add databases for other liquids after the campaign ends.

Further information

The π-LAB is available on Kickstarter through Oct. 30 starting at 339 Euros ($401), with shipments due in Jan. or Feb. 2022, depending on the package. At publication time, the project had earned less than $2K of its $68K plus goal. More information may be found on the π-LAB Kickstarter page.