12.Force-Sensitive Resistor - Spark Core

Let’s read data sheet (PDF ). It says resistance changes 1K - 100K (roughly linear).
I used 10K ohm resistor to measure as follows.

In theory, if you touch the censor, resistor values decreases and the voltage increases. So simply read the voltage using A0.

// Force-Sensitive Resistor
//  

#include <stdarg.h>

#define PRINTF_BUFFER_SIZE 128
void Serial_printf(const char* fmt, ...) {
   char buff[PRINTF_BUFFER_SIZE];
   va_list args;
   va_start(args, fmt);
   vsnprintf(buff, PRINTF_BUFFER_SIZE, fmt, args);
   va_end(args);
   Serial.println(buff);
}

void setup() {
  Serial.begin(9600);
  pinMode(A0, INPUT);
}

void loop() {
  Serial_printf("%d", analogRead(A0));
  delay(400);
}

It worked for me!