InfraRed Flame Sensor for RCX
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Limited Stock        IRFL    InfraRed Flame Sensor for RCX     $39.00  

Find a candle or the sun.

The infrared Flame sensor detects Infrared light, which is also called radiated heat. The heat may be produced by a candle, the sun, or an incandescent lamp. This sensor sends a number to your RCX computer indicating how much heat it is measuring. Your program can make decisions based on this number. Your robot can find a candle or light bulb and go to it. This sensor is compatible with the Lego Mindstorms RCX System.

  
 


Programming

The IR Flame Sensor is programmed like a light sensor.  You may use any of the Lego light sensor icons with it.

For higher resolution the sensor can be read in RAW mode. The robolab program below reads the sensor in raw mode and turns on port A if the sensor value is greater than 800.  The raw value is displayed.


Interference

The IR flame sensor detects any form of Infrared light. The sensor may also detect:

•  Incandescent lamps.

•  Direct or reflected sunlight.

•  Hot objects like electric heaters.

•  Infrared remote control devices.

A room with a lot of sunlight or incandescent lamps may flood the sensor with IR radiation, making it difficult to distinguish a candle from the background light.  You can reduce the effect of background light by using a view restrictor.  This limits the sensor's view to a narrow cone, like blinders on a horse.  The sensor comes with two view restrictors for medium and narrow field of vision.

 

 

The sensor also has a sensitivity control which allows you to reduce the sensitivity when the sensor is being flooded with background light.  Use a small screwdriver to turn the dial clockwise to reduce sensitivity.  This also reduces sensitivity to the candle flame.  The sensor will alway work best in a room that has only flourescent lights and no windows.


Specifications

Technical Description

The sensing element is a phototransistor with peak sensitivity in the near infrared. It is packaged in plastic that blocks visible light. The sensitivity control adjusts the maximum current through the phototransistor. You can adjust the current to compensate for a “bright” environment that would otherwise saturate the transistor.