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    Arduino UNO: Flex Sensor and LEDs Reviewed by Unknown on 21:48 Rating: 4.5

    Arduino UNO: Flex Sensor and LEDs

    Oleh Unknown
    Using the same LED matrix as before, and swapping the Photo Resistor for a Flex (or Bend) sensor, and a slight modification to the code, I can now have a light show that can be controlled by "Bending".

    I used my finger to bend the sensor, but I could have attached it to a plant, a tree or anything else that bends. The bending changes the resistance, and therefore the INPUT value at analog pin 0.

    The parts required:
    • Arduino UNO
    • 10 x Red LEDs
    • 9 x 330 Ohm resistors for the LEDs
    • 1 x 10K Ohm resistors for the flex sensor.
    • 1 x Flex sensor
    • Wires and Breadboard to connect it all together
    Most of the components needed for this project can be sourced from the Sparkfun Inventor's Kit

    The video:


    The Sketch:







































    The Arduino Code:  


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    /*
    Flex Sensor and LEDs created by ScottC on 23rd May 2011
    updated on 16/05/2012.

    -----------------------------------------------------*/

    //Flex Sensor Pin (flexPin)
    //the analog pin the Flex Sensor is connected to
    int flexPin = 0;  
                      
    void setup() {
      for (int i=4; i<14; i++){
        pinMode(i, OUTPUT); //sets the led pins 4 to 13 to output
      }
    }

    void loop(){
     //Ensure to turn off ALL LEDs before continuing 
     for (int i=4; i<14; i++){
        digitalWrite(i, LOW); 
      }
     
     /* Read the flex Level 
      Adjust the value 130 to 275 to span 4 to 13
      The values 130 and 275 may need to be widened to suit 
      the minimum and maximum flex levels being read by the 
      Analog pin */
     int flexReading = map(analogRead(flexPin), 130, 275, 4, 13); 
             
    // Make sure the value does not go beyond 4 or 13
     int LEDnum = constrain(flexReading, 4, 13); 
     
    /*Call the blink function: this will turn the LED on for 10 milliseconds, and keep it
      off for only 1 millisecond. You can change the blink rate by changing these values,
      however, I want a quick response time when the flex sensor bends, hence the small 
      values. LEDnum determines which LED gets turned on.*/
     blink(LEDnum, 10,1);
    }

    // The blink function - used to turn the LEDs on and off
    void blink(int LEDPin, int onTime, int offTime){
      // Turn the LED on                                         
     digitalWrite(LEDPin, HIGH);  
     
      // Delay so that you can see the LED go On.
     delay(onTime);
     
      // Turn the LED Off                                         
      digitalWrite(LEDPin, LOW);  
     
     // Increase this Delay if you want to see an actual blinking effect.
      delay(offTime);
    }


    The flex sensor pins/legs are a bit fragile, so be careful when poking it into the breadboard.


    For more projects - have a look at the ArduinoBasics Project Page

    Description: Arduino UNO: Flex Sensor and LEDs Rating: 3.5 Reviewer: Unknown ItemReviewed: Arduino UNO: Flex Sensor and LEDs
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