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An inexpensive device for analyzing roasted coffee beans

Arduino TeamDecember 18th, 2018

While you may not consider in detail how your coffee is roasted, those that produce it must pay special attention to make sure that the end product is consistent. Equipment to help analyze roasted coffee is normally quite expensive, but using a near-infrared sensor, Arduino Uno and Bluetooth module, Spencer Corry was able to make his own analysis setup.

As shown in the video below, after calibration, beans are inserted into the analysis chamber using a tryer scoop. Light is shined onto the roasted beans, and the intensity of the reflected near-infrared radiation is analyzed in six different wavelengths. Intensity data is then transmitted via Bluetooth to a smart device, which can be used to make sure things are roasted perfectly.

There has recently been a growth of small roasting companies offering custom in-house roasts. These companies are looking for less expensive alternatives to hiring and training a roast master or using the expensive Agtron Process Analyzer. The Degree of Roast Infrared Analyzer for Coffee Roasters, as described in this document, is meant to be an inexpensive means of measuring the degree of roast of coffee beans. The Degree of Roast Infrared Analyzer uses a tryer, a tool found on coffee roasters used to sample the coffee during roasting, to hold a sample of coffee. The tryer is inserted into the analyzer where the AS7263 NIR Spectral sensor is used to measure 6 different infrared bands (610, 680, 730, 760, 810, and 860nm). The reflectance measurements are transmitted via Bluetooth and can then be correlated to the degree of roast. The analyzer must first be calibrated by pressing a button on the inside of the box in which the PVC is used as a white balance as it has a relatively flat reflectance in the spectral range detected by the sensor.