This week’s EYE ON NPI is catchy like an 80’s pop song, it’s ams OSRAM’s TCS3530 True Color Sensor.
It is a new light sensor from ams OSRAM that is pre-calibrated for CIE XYZ color temperature sensing output, without a lot of gnarly math!
We’re huge fans of ams’s light sensors, one of our first sensor breakouts was the TSL2561, a wide-input-range light sensor with an I2C interface.
We followed that up with a breakout for the TCS34725 which can detect separate red, green, blue and clear channels. With a little math, color reflected off of objects can be calculated into RGB color-space – we used it to make an umbrella that matches whatever color it touches!
Since then, ams OSRAM has worked to create better light sensors that reduce the need for end-user calibration or a lot of microcontroller lifting. The chips have carefully tuned PN diodes to not only be able to report correct color values, but ideally also have little variation from sensor-to-sensor.
The TCS3530 is the latest color sensor from ams OSRAM, and it’s also their newest with XYZ color output! This means you can read CIE XYZ color values out directly from the driver, which is going to be the best way to model what a human eye sees – not just an optimal concept based on ‘pure’ RGB photodiodes.
This makes it ideal for use with cameras, monitors, printers/copiers and other devices that have humans that are looking at the colors.
By detecting ambient light temperature, monitors and camera sensors can adjust their white balance to have their color gamut appear more ‘natural’ even in yellowish incandescent or halogen, or blueish fluorescent light.
The TCS3530 does this by having 8 separate PN diodes, each tuned to a specific frequency band, to cover from about 400nm to 750nm. The diodes are normalized by the ALS engine so that you don’t get over-sensitivity to green or IR.
The diodes are arranged in a 4-way symmetric array to get fully balanced readings across all frequencies: there’s probably some reasoning to how the layout is done to avoid signal from one diode from affecting a nearby one, something ams has decades of experience with.
A modulator and flicker detection system can sense light pulses such as those from incandescent bulbs (at 120 Hz) or monitors (30 to 60 Hz) so that we can sample at the same times during the wave, or sample long enough to capture a full waveform worth of light.
Interfacing is fairly simple, although there are a few things to watch out for during integration. The sensor supports both I2C and I3C so it’s good for legacy or modern microprocessors. Note the chip requires no greater than 1.8V power and logic, so for 3.3V systems – a shifter will be necessary. Finally – the chip has a massive number of registers to tweak the settings. So while you could write a driver, you’re probably best off using ams OSRAM’s TCS3502 linux C kernel driver to base your implementation if you are not just using Linux/Android directly.
If you want to add precision color sensing with pre-calibrated CIE XYZ outputs to your next design, the ams OSRAM’s TCS3530 True Color Sensor is a top choice from a world leader in light sensing. And best of all, it’s in stock right now at DigiKey for immediate shipment! Order today and you will get this compact all-in-one devices shipped to your door so you can start letting your true colors shine by tomorrow afternoon.
See the video below:
