Tutorial: Flex Sensor with Arduino

On this tutorial, we will use the Arduino to read a flex sensor. The flex sensor is a device that changes its resistance proportional to its form, like this:

If the sensor is straight, it outputs 30k, it is flexed, 50k. With an Arduino board, make this circuit:

The resistor makes a voltage divider to make the reading possible. The analog input A0 is our signal.

Open the Arduino IDE and upload the following code. This code shows how many degrees the sensor is flexed.

// Flex sensor test program

// Mike Grusin, SFE, 2011
// This program is free, use it however you wish!

// HARDWARE:
// Make the following connections between the Arduino and the flex sensor
// Note that the flex sensor pins are interchangeable

// Sensor pin - GND
// Sensor pin - Analog In 0, with 10K resistor to +5V

// INSTRUCTIONS:
// Upload this sketch to your Arduino, then activate the Serial Monitor
// (set the Serial Monitor to 9600 baud)

void setup()
{
    // initialize serial communications
    Serial.begin(9600); 
}

void loop()
{
    int sensor, degrees;

    // read the voltage from the voltage divider (sensor plus resistor)
    sensor = analogRead(0);

    // convert the voltage reading to inches
    // the first two numbers are the sensor values for straight (768) and bent (853)
    // the second two numbers are the degree readings we'll map that to (0 to 90 degrees)
degrees = map(sensor, 768, 853, 0, 90);
    // note that the above numbers are ideal, your sensor's values will vary
    // to improve the accuracy, run the program, note your sensor's analog values
    // when it's straight and bent, and insert those values into the above function.

    // print out the result
    Serial.print("analog input: ");
    Serial.print(sensor,DEC);
    Serial.print(" degrees: ");
    Serial.println(degrees,DEC);

    // pause before taking the next reading
    delay(100); 
}

Upload the code and open the serial monitor to see the results.

That's it!

References:

http://www.sparkfun.com/products/10264

http://www.sparkfun.com/datasheets/Sensors/Flex/flex22.pdf

http://www.sparkfun.com/tutorials/270

Views: 16350

Tags: arduino, flex, sensor, tutorial

Comment

You need to be a member of GarageLab (arduino, electronics, robotics, hacking) to add comments!

Join GarageLab (arduino, electronics, robotics, hacking)

Latest Activity

GarageLab posted blog posts
10 hours ago
Chris is now a member of GarageLab (arduino, electronics, robotics, hacking)
10 hours ago
soheil gharatappeh commented on GarageLab's blog post Tutorial: How to use a Shield RS485 and USB/RS485 Converter with Arduino
"Can you describe what is the reason for this line? KEY = map(digitalRead(4), 0, 1, 0, 1);it maps a…"
yesterday
GarageLab posted a blog post

Ubuntu Core running on the Raspberry Pi 2 with access to GPIO

Although not officially Ubuntu Core makes progress and will not be pass behind by the IoT Windows…See More
Tuesday
Profile Iconsoheil gharatappeh, Bill Mills and Jory Hickman joined GarageLab (arduino, electronics, robotics, hacking)
Tuesday
GarageLab posted a blog post

Project Sunroof

Now Google aims to help people evaluate the potential of their roofs to generate electricity. The…See More
Monday
GarageLab posted blog posts
Aug 28
Profile IconGaroppolo, meke, M N Ranganathan and 1 more joined GarageLab (arduino, electronics, robotics, hacking)
Aug 28
GarageLab posted a blog post
Aug 26
GarageLab posted blog posts
Aug 25
Profile IconDennis P Smith, Ronald Ong Jr., FRANK KWABENA and 4 more joined GarageLab (arduino, electronics, robotics, hacking)
Aug 24
GarageLab posted a blog post
Aug 20
Achyut Raj is now a member of GarageLab (arduino, electronics, robotics, hacking)
Aug 20
Profile IconJorge Luis Antezana B., Andre, Evan conger and 1 more joined GarageLab (arduino, electronics, robotics, hacking)
Aug 19
GarageLab posted blog posts
Aug 18
Denver S Conger posted a photo
Aug 17
Denver S Conger updated their profile
Aug 17
Profile Iconalain and Xolbrin joined GarageLab (arduino, electronics, robotics, hacking)
Aug 17
GarageLab posted blog posts
Aug 14
Jean Luc Claveur is now a member of GarageLab (arduino, electronics, robotics, hacking)
Aug 14

© 2015   Created by Marcelo Rodrigues.

Badges  |  Report an Issue  |  Terms of Service