Tag Archives: color sensor

MicroSemi’s Precision Colour Sensor AS73211

Precision colour sensing made easy

Austrian MicroSemi recently divested itself of its transceiver portfolio, leaving standards such as AS-I stranded. Sensors were selected as the new main field of business, leading to the introduction of a few extremely interesting products such as the JENCOLOR colour sensor ICs.

In principle, the sensor is laid out according to the schemes shown in the two figures accompanying the screen. The main priority is that the part contains but three photo-diodes, all three of which are conveniently located behind a filter to eliminate unwanted spectral components.

The three diodes are located in seperate areas of the main die…

…AMS provides a relatively complex set of signal conditioning circuits

To clarify a few aspects: first of all, the AS73211 is strictly an one-pixel color detector – it has nothing to do with the traditional linear or two-dimensional CCD chips which are well-known from digital cameras. Secondarily, the chip’s intended usage is processes – think about quality control, sorting of goods and similar tasks where accurate color sampling is required.

Finally, the AS73211 is intended to reach extreme high accuracies – its internal DACs can work at 24bit if required.

When compared to a homebrew solution, benefits pop up. ADC linearity and temperature issues are handled by AMS – the chip contains various bits of logic which ensure that issues affecting resolution adversely are handled effectively.

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The Aurora Boxealis – A Color Sensing and Mirroring Project

Besides looking damned good on an otherwise bland and ordinary desk, this project is about more than just being attention grabbing eye candy.  It’s about demonstrating a small portion of our single board computer capabilities by hooking up a color sensor, RGB light strip, and enclosing it in a nice looking wooden enclosure.  We’re dubbing it the “aurora boxealis”, and it’s made to stand out from the crowd at trade shows and provide a fun, interactive way to professionally demonstrate an interesting sensor, in this case a color sensor.  Grabbing a color swatch from the table and placing it on the top of the box will trigger the lights to mirror that color.

The Aurora Boxealis – A Color Sensing and Mirroring Project – [Link]

Color sensor achieves high dynamic range with auto exposure

Massimo Gottardi@ edn.com writes:

The Design Idea in Figure 1 is a color detector capable of generating an RGB triplet over a high dynamic range, a useful attribute for machine vision applications. The circuit implements auto-exposure control to achieve this. Thus, RGB values for a subject are invariant over a range of light intensity.

Color sensor achieves high dynamic range with auto exposure – [Link]