Arduino Flex sensor help (ergent)

Forum 2005-2010 (read only) Hardware Interfacing
1

Alright so i have an arduino and a servo and a flex sensor i have tried out code with a presure censor:

/*
Servo control from an analog input

The minimum (minPulse) and maxiumum (maxPulse) values
will be different depending on your specific servo motor.
Ideally, it should be between 1 and 2 milliseconds, but in practice,
0.5 - 2.5 milliseconds works well for me.
Try different values to see what numbers are best for you.

This program uses the millis() function to keep track of when the servo was
last pulsed. millis() produces an overflow error (i.e. generates a number
that's too big to fit in a long variable) after about 5 days. if you're
making a program that has to run for more than 5 days, you may need to
account for this.

by Tom Igoe
additions by Carlyn Maw & Rob Faludi
Created 28 Jan. 2006
Updated 10 Jun. 2008
*/

int servoPin = 2; // Control pin for servo motor
int minPulse = 500; // Minimum servo position
int maxPulse = 2500; // Maximum servo position
int pulse = 0; // Amount to pulse the servo

long lastPulse = 0; // the time in milliseconds of the last pulse
int refreshTime = 20; // the time needed in between pulses

int analogValue = 0; // the value returned from the analog sensor
int analogPin = 0; // the analog pin that the sensor's on

void setup() {
pinMode(servoPin, OUTPUT); // Set servo pin as an output pin
pulse = minPulse; // Set the motor position value to the minimum
Serial.begin(9600);
}

void loop() {
analogValue = analogRead(analogPin); // read the analog input
pulse = map(analogValue,0,1023,minPulse,maxPulse); // convert the analog value
// to a range between minPulse
// and maxPulse.

// pulse the servo again if rhe refresh time (20 ms) have passed:
if (millis() - lastPulse >= refreshTime) {
digitalWrite(servoPin, HIGH); // Turn the motor on
delayMicroseconds(pulse); // Length of the pulse sets the motor position
digitalWrite(servoPin, LOW); // Turn the motor off
lastPulse = millis(); // save the time of the last pulse
}
}

i have built that and when i replaced the presure sensor i got from sparkfun it only turns the servo less then 90 degrees when i have the presure sensor on it turn the maximum of 180 degrees

please i really need your help and fast thank you

2

Alright so if I could post a link I would and it would be a lot easier tell me prob. Alright so I have built a circuit with a presure sensor so the harder u press the more the servo will rotate. Then I tried putting a flex sensor in an it dosnt seem to work at all it turn less then 90degrees. So maby I have the code wron or maby the wrong resistor I jut don't know

Thank you

3

Alright i noticed i do have a map function in the code above but could u maby give me just a sample code to play with and get it fined tuned that controlles a servo

thank you

4

alright so the link u gave me about the map()... like idk what to do from here because i do have the map() in my code but its confusing with the variables but how do u want me to do this if u were me find he esistance through a multimeter ot what

5

alright so what i got is for the
flex sensor: 500-200
presure sensor:0-950

6

alright so i pretty much got it working but when i flex the sensor about 90 degrees it does the maximum servo command adn i want it around 180 degrees you have to flex it

7

alright so i got that too i just changed the 1023 to a 0 and the 0 to a 500 and here is my final code:

/*
Servo control from an analog input

The minimum (minPulse) and maxiumum (maxPulse) values
will be different depending on your specific servo motor.
Ideally, it should be between 1 and 2 milliseconds, but in practice,
0.5 - 2.5 milliseconds works well for me.
Try different values to see what numbers are best for you.

This program uses the millis() function to keep track of when the servo was
last pulsed. millis() produces an overflow error (i.e. generates a number
that's too big to fit in a long variable) after about 5 days. if you're
making a program that has to run for more than 5 days, you may need to
account for this.

by Tom Igoe
additions by Carlyn Maw & Rob Faludi
Created 28 Jan. 2006
Updated 10 Jun. 2008
*/

int servoPin = 2; // Control pin for servo motor
int minPulse = 500 ; // Minimum servo position
int maxPulse = 4000; // Maximum servo position
int pulse = 0; // Amount to pulse the servo

long lastPulse = 0; // the time in milliseconds of the last pulse
int refreshTime = 20; // the time needed in between pulses

int analogValue = 0; // the value returned from the analog sensor
int analogPin = 0; // the analog pin that the sensor's on

void setup() {
pinMode(servoPin, OUTPUT); // Set servo pin as an output pin
pulse = minPulse; // Set the motor position value to the minimum
Serial.begin(9600);
}

void loop() {
analogValue = analogRead(analogPin); // read the analog input
pulse = map(analogValue,500,0 ,minPulse,maxPulse); // convert the analog value
// to a range between minPulse
// and maxPulse.

// pulse the servo again if rhe refresh time (20 ms) have passed:
if (millis() - lastPulse >= refreshTime) {
digitalWrite(servoPin, HIGH); // Turn the motor on
delayMicroseconds(pulse); // Length of the pulse sets the motor position
digitalWrite(servoPin, LOW); // Turn the motor off
lastPulse = millis(); // save the time of the last pulse
}
}