Help with light sensors

NuzakFarnas's picture

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Joined: Nov 01, 2019

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Help with light sensors
November 1, 2019 - 12:25pm

I am a rookie with electronics, but I am hoping someone can tell me if I am able to hook up approx 50 light sensors to an arduino, so it can tell me how many of them are blocked from light. Hopefully that makes sense and any help is much appreciated. I am wanting to perform a calculation with the result from how many are blocked. TIA.

 
AISHA's picture

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50 LDR with Arduino?
November 3, 2019 - 4:53pm

Buy light sensor I assume that you are referring to LDRs. Technically yes, it is possible to connect 50 light sensors to an Arduino but I wonder why anyone would do that. 

Few things to consider - are you trying to measure the intensity of light (Analog) or just check if it is total bright or dark (Digital). The problem here is Arduino UNO, for example, has only 14 digital pin and 6 analog pins. So you can only connect 14 digital sensor and 6 analog sensors to it. 

But if for some reason you want to connect 50 sensors then you should use a multiplexer or external ADC modules. The choice depends on your application requirement 

jaksonlee's picture

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The VEX light Sensor allows
November 15, 2019 - 11:48am

The VEX light Sensor allows the robot to sense the ambient light in a room. Unlike the Line Tracking Sensor, the Light Sensor does not generate any light, it only senses the amount of light already present in an area. The Light Sensor is an analog sensor, and it returns values in the range of 0 to 4095. Higher values indicate that the sensor is in a darker area, and lower values indicate lighter areas.

Some uses of the Light Sensor would be to have your robot stop moving whenever the lights in a room are swtiched off, or to sense when it moves into a shadow. When attaching the Light Sensor to your Robot, remember that it reads ambient light, so that it functions best when facing out into an open space. The Light Sensor can reliably sense light from up to six feet away from a light source. The sensor only senses visable light, and is not sensitive to infrared or ultraviolet light.

sacarlett leo's picture

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I hope you found your
November 20, 2019 - 10:53am

I hope you found your solution. 

jaksonlee's picture

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A light sensor detects when a
November 20, 2019 - 5:26pm

A light sensor detects when a person or object moves in front of it and activates a light, which shines on a specified area. Sensor-activated flood lights help to keep the home safe and deter suspicious activity. Once the lighting system and sensor are installed, you might need to know how to configure the unit to suit your particular purpose. You also should program and test the system correctly before leaving your home for extended periods.

Twist the "Lite" and "Time" control knobs  counterclockwise until they each point to "Test." Twist the "Sens (Sensor)" control knob  to its middle setting. Turn on the floodlight switch and allow the light a minute to warm up, then turn off.

Adjust the sensor to cover the area you desire. Aim the sensor down to narrow the sensor area, or aim the sensor up to broaden the sensor area.

Twist the "Time" knob clockwise to lengthen the amount of time the floodlight remains on after the sensor is triggered.