Everything is getting smarter today and the new product from the traditional Japanese company Hamamatsu Photonics is not just a sensor anymore, but smarter. Containing a photodiode, LED and an IC chip inside a space-saving SMD package, this new smart sensor P12347-01CT enables new possibilities.
4 Functions  in 1 product

The new smart sensor P12347-01CT contains 4 functions in 1 product, which saves space and cost by smart integration. Typically these functions are used in all kind of consumer devices such as tablets, smart phones, TVs, multimedia screens in cars, and automatic switches.

Smart Sensor

The first function is a reflective lightbarrier, which is used as a proximity sensor. It uses the light from the red LED, which is reflected to the Silicon photodiode by an approaching object. The detectable distance is 30mm +/-20%, which is adjustable by the LED drive current. By optical modulation, the background light is reduced to prevent detection errors.
This can be used for automatic, contact-free switches in all kind of applications, for example to switch ACC or other systems in the car on and off. It can also be used to deactivate a phone display when it approaches the ear. In the same way, displays can be activated or even operated by gestures without touching the screen.


Ambient light sensor
The second function is an ambient light sensor for brightness control. A silicon photodiode with high sensitivity from 1 mlx is used and a 16-bit analog-digital converter (ADC) for signal processing is already implemented in the IC-chip.
Ambient light sensors are helpful to set displays brighter or darker according to the actual light conditions, to switch automatic headlights on and off,  and to adjust interior car illumination.

Ambient light sensor

Colour sensor
In addition to the simple illuminance measurement, the Silicon photodiode has also 3 channels with RGB filters and an IR channel, which enable to measure not only light intensity, but also colour. The colour measurement is helpful to analyze the incident light in more detail. This can be light from the LEDs to adjust them, or the ambient light to classify the kind of lightsource. With that, the ambient light functions can be improved, or displays can be adjusted for better image quality.  
LED indicator
The fourth function is a coloured indicator light by the integrated red, green and blue LEDs. Usually separate LEDs are used for an indicating function, so the integration into this smart sensor makes sense as it saves on costs and space.
A switch can be illuminated for example in red for ’’off’’ and green for ’’on’’, or a blinking red signal can indicate a new incoming message or can be used as a warning signal inside the car.
Other features
The smart sensor integrates these 4 functions inside a small flip chip SMD package. This stable and reliable package survives 260°C automatic reflow soldering and with only 5.5 x 1.7 x 1.0 mm size it is smaller than the usually one single packaged standard LED.


Using an I2C interface to connect with a control unit, the smart sensor is a fast and easy to operate digital device. It has a low power consumption and is operated with a supply voltage between 2.25 and 3.63V and an I²C bias of 1.65V.
New applications enabled
With this smart sensor new possibilities for future applications will arise. All applications which usually use a sensor and LED in combination could profit from this new package idea, if space and cost saving is important. For example there are several spectroscopy applications which could use such a concept, especially if they are integrated in small, mobile devices.
Heart rate
One application example is to use the integrated green LED of P12347-01CT to measure the heart rate, which uses the light absorption by hemoglobin in the blood. This can be used for mobile heart rate measurements for fitness or health checking, which are increasingly used, and can also be combined with a smart phone app.
Moisture detection
Another idea for the future is to use components for the near infrared range in the same package to detect for example moisture by light absorption in a very simple way. Moisture detection is used in many products; one example is measuring the moisture content of the skin in the cosmetics industry, to determine the suitable cosmetic products for the skin type. 

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