Modules integrate ambient light sensor with infrared receiver

19th July 2018

Mick Elliott

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A range of miniaturised sensor modules including a two-in-one ambient light sensor with infrared receiver is now offered by UK firm Selectronic. The modules are part of a key range of integrated sensors available from the Witney, Oxfordshire-based company which marks its 40th anniversary in 2019.

The ALS plus IR product is targeted at digital AV equipment - but the Selectronic range of products includes many applications including IR receivers, ambient light sensors, CCTV and security devices, safety cut-off devices and production line controls. They are also used in a diverse range of consumer products such as TV and AV equipment, cameras and phones, fridges and freezers, as well as lighting in the home, car or street.

The miniaturised two in one ALS plus IR Receiver RIS-F3G5XNMxx series is the newest in the range and is made of a clear epoxy transfer mould package on a lead frame. The IR module has excellent performance even in disturbed ambient light application and provides protection against uncontrolled output pulses.The ALS is an advanced digital ambient light sensor that transforms light intensity to a digital signal output.

For ambient light sensing, the ALS has two opened photodiodes (CH0/CH1).

One is a whole ray responding photodiode, the other a visible ray responding photodiode coated with an infrared cut off filter on a CMOS integrated circuit.

The photovoltaic responses are converted into digital counter values by two internal ALS ADCs of 16 bit resolution.

“The final result if the product closely approximates the human eye spectral response of visible wavelength,” said Selectronic MD Kevin Dry.

The IR receiver operates at 940nm and versions are available with band pass frequencies of 32.7, 36, 37.9 and 40kHz.

It incorporates AGC and has an integrated wave shaping function. The minimum arrival distance (detection range) is 15m.The ambient light sensor is an advanced digital ALS that transfers light to a digital signal output. The PV responses are converted to digital counts using two internal ASLS 16 bit ADCs. The device also includes an I2C module so that all information can be accessed directly via a serial bus - making system integration easy.

“With an operating temperature range of -20 to 80 degrees C the device can be used in a wide range of conditions.”added Dry.