MicroSemi AS73211 Precision Colour Sensor

Precision colour sensing made easy

MicroCrystal RV-8803 – A Really Accurate RTC June 17, 2019- RTC chips traditionally were the domain of Maxim and NXP. Switzerland-based MicroCrystal recently made quite a buzz with its RV-8803, which offers simple integration, an I2C interface and extreme accuracy. Let us start out by looking at a system overview. Figure one shows how this I2C RTC is made up internally – interested observers note … Continue reading MicroCrystal RV-8803 – A Really Accurate RTC
Analog Devices’ LTM2887 – If a Digital Bus Needs Galvanic Isolation June 15, 2019- In theory, digital buses are intended to connect things to one another. Sadly, one sometimes wants but a logical connection – in many cases, galvanic isolation helps out. Should you ever feel like isolating very fast buses, definitely give the LTM2887 a chance. From a technical point of view, Linear Technologies attempt at entering the … Continue reading Analog Devices’ LTM2887 – If a Digital Bus Needs Galvanic Isolation
AVAGO APDS-9008 or APDS-9005-020 – Keeping an Eye on Ambient Light June 14, 2019- Recent times saw quite a bit of interest for part numbers such as the APDS-9008 or APDS-9005-020 – they are a very interesting type of ambient light sensor. One of the oldest questions in regards to light sensors involves their spectral sensitivity. If a part is to output but one voltage level, the conversion between … Continue reading AVAGO APDS-9008 or APDS-9005-020 – Keeping an Eye on Ambient Light
STMicroelectronics’ LIS2DH12 – Low Power Motion Sensing June 12, 2019- Apple’s iPhone introduced gyroscopic sensors to a wider range – before that, accelerometers were not commonly found in consumer hardware. STM sells excellent parts which, however, get little media attention – time to take a look at the LIS2DH12. Integrating the part into your circuit as an MPU6500 alternative or MPU9500 alternative is not difficult. … Continue reading STMicroelectronics’ LIS2DH12 – Low Power Motion Sensing
Panasonic AMG8833 – FLIR for cheap June 7, 2019- FLIR made infrared thermal sensors cool – sadly, their parts are all but cheap (and suffer from export control problems). Panasonic’s Grid-EYE family is a low-resolution alternative which comes at significantly lower cost. From a technical point of view, Panasonic’s image sensor could not be simpler. We are looking at an 8×8 sensor with an … Continue reading Panasonic AMG8833 – FLIR for cheap
DipTronics DTS-62R-V – Small Switch, Very Big (and Very Cheap) June 5, 2019- When yours truly was but a lowly cadet, various US manufacturers produced (pricey but quite reliable) switches. Chinese vendors recently started to catch up – seeing the DTS-62R-V top our customer interest list shows that the run stage of the crawl-walk-run cycle is reached. DipTronics has been around the Asian switch market for ages, exhibiting … Continue reading DipTronics DTS-62R-V – Small Switch, Very Big (and Very Cheap)

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.


Program me!

Getting data out of the part is accomplished via an insutry standard I2C connection. In the first step, both CREG1:GAIN and CREG1:TIME must be programmed to set up ADC gain and the time spent on the individual conversion cycles. In the next step, the remaining hardware must be configured – when done, actual measuring processes can be triggered. More information on this is readily available in the excellent datasheet, which is waiting for you here.
On development kits

Like most other optical systems, the AS73211 also puts demands on the accompanying optics. Developers working on sensor software are well-advised to start out by buying the (somewhat pricey) AS73211-AB5 SET DK development kit rather than the basic PCB version – the former comes with a complete optical assembly, thereby taking one bit of hassle off your neck.

… Be careful when selecting your development kit – not all are created equal