Force Sensitive Resistor Round 0.5

0.5 "force sensitive resistor (FSR) is a quick way to measure the pressure, and is very easy to setup. FSR depending on how much pressure is applied to the sensing area, its resistance to change. The greater the ball, the less resistance. When measured with a multimeter , the sensor is greater than 1MΩ when no pressure is applied to a resistance.

As an example, we have a simple resistor voltage divider circuit using an Arduino UNO and will measure the force.

Force Sensitive Resistor Round 0.5

27kΩ standard 0-5V output voltage from the best "sweet" to have been selected, assuming that the sensing range of the sensor (resistance sweets) 0-100kΩ is. UNO A0 output voltage sensors with wires attached and the other (27kΩ) to prevent the jumper, are welded. If you're new welded, welded 101, be sure to read the tutorial.

Force Sensitive Resistor Round 0.5

Using this circuit, we can read the analog inputs of 0, and the Arduino 5V representing return a value somewhere between 0 and 1023, with 1023. When pressure is applied to the sensor value decreases. This is proof that the circuit works, but what we want to calculate the value of the sensor resistance? We use this equation to a voltage divider can find:

VO / VI = Rfsr / (R1 + Rfsr)

In this case, Arduino VAL is measured. Since its output is 0-1023, 1023 5V with representing, we can replace the sixth with 1023. Also, since we know that the value of R1 27kΩ, the equation becomes:

VO / 1023 = Rfsr / (27000 + Rfsr)

Lfsr solution to use a bit of algebra, we get:

Rfsr = (26.4 * VO) / (1 - (VO / 1023))

Keep in mind that, Rfsr 27kΩ resistor value of this equation only works for R1. Now we can plug this to our Arduino sketch, VO, such as the value of A0, and FSR resistance au Print

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//*****************************************************************************
// Example Sketch for the 0.5" Force Sensitive Resistor
// 3/17/11
// 
// Set up the FSR as R2 of voltage divider circuit with R1 a value of 27k
// Vout connected to Analog input 0
// Prints resistance value of FSR
// 
// WARNING: Resistance value only valid for 27k resistor if using a different
// value, use the equation
// 
//    x = (Rfsr/(R1+Rfsr))*1023
//
// where x is the value from A0, and R1 is the non-FSR resistor, to find the 
// FSR resistance in Ohms. 
//
// To find the actual weight applied to the sensor, refer to the graph on page
// 5 of the datasheet (theoretical values only!) or calibrate the circuit using
// of a known weight. 


//*****************************************************************************


#define FORCE 0

float value = 0;
float resistance = 0;

void setup()
{
  Serial.begin(9600);
  Serial.println("0.5\" Force Sensitive Resistor Test");
}

void loop()
{
  value = analogRead(FORCE);
  resistance = ((26.4 * value)/(1-(value/1023.0)));
  Serial.println(resistance,DEC);  
  
  delay(200);
}

The sketch in order to translate the actual force applied to the FSR estimated resistance of the resistance will be printed. FSR's datasheet you can refer to the graph on page five:

Force Sensitive Resistor Round 0.5

Please note, however, that the real power to prevent the implementation of the application you're using and the FSR is heavily dependent on tolerance. In order to determine an actual weight, it is recommended that an exploratory force / resistance curve ball with a known structure in order to calibrate the sensor. Otherwise, the sensor for detecting the weight shift and the relative strength of things like the great.