Flex sensors problem with arduino uno without breadboard

iulianapavel123 · May 25, 2023, 3:37pm

Hi. I have a big problem and I need help. my project is a collar that includes 2 flexion sensors placed on the neck inside the collar and connected to the arduino uno board. I would like the angles to be displayed on the i2c lcd. I wrote the code but when I run it nothing happens, the display stays off and nothing happens. I checked the cables, the power supply and the display. the lcd display works without the sensors connected to the board. can you help me ? this is how they are connected and this is the code.

const int FLEX_PIN_1= A0; // Pin connected to voltage divider output
const int FLEX_PIN_2= A1; // Pin connected to voltage divider output

// Measure the voltage at 5V and the actual resistance of your
// 47k resistor, and enter them below:
const float VCC = 4.70; // Measured voltage of Ardunio 5V line
const float R_DIV_1 = 10000.0; // Measured resistance of 3.3k resistor
const float R_DIV_2 = 10000.0; // Measured resistance of 3.3k resistor

// Upload the code, then try to adjust these values to more
// accurately calculate bend degree.
const float STRAIGHT_RESISTANCE = 37300.0; // resistance when straight
const float BEND_RESISTANCE = 90000.0; // resistance at 90 deg
const int LCD_Vcc = 11;
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,16,2); // set the LCD address to 0x27 for a 16 chars and 2 line display

void setup()
{
lcd.begin(16, 2);
Serial.begin(9600);
pinMode(FLEX_PIN_1, INPUT);
pinMode(FLEX_PIN_2, INPUT);
pinMode(LCD_Vcc, OUTPUT);

 digitalWrite(11, HIGH);

}

void loop()
{
// Read the ADC, and calculate voltage and resistance from it
int flexADC_1 = analogRead(FLEX_PIN_1);
int flexADC_2 = analogRead(FLEX_PIN_2);
float flexV_1 = flexADC_1 * VCC / 1023.0;
float flexV_2 = flexADC_2 * VCC / 1023.0;
float flexR_1 = R_DIV_1 * (VCC / flexV_1 - 1.0);
float flexR_2 = R_DIV_2 * (VCC / flexV_2 - 1.0);
Serial.println("Resistance: " + String(flexR_1) + " ohms");
Serial.println("Resistance: " + String(flexR_2) + " ohms");
digitalWrite(LCD_Vcc, HIGH);
lcd.setCursor(0,0);

// Use the calculated resistance to estimate the sensor's
// bend angle:
float angle_1 = map(flexR_1, STRAIGHT_RESISTANCE, BEND_RESISTANCE,
0, 90.0);
Serial.println("Bend: " + String(angle_1) + " degrees");
Serial.println();
// bend angle:
float angle_2 = map(flexR_2, STRAIGHT_RESISTANCE, BEND_RESISTANCE,
0, 90.0);
Serial.println("Bend: " + String(angle_2) + " degrees");
Serial.println();
lcd.print("Bend: " + String(angle_1) + " degrees");
lcd.setCursor(2,1);
lcd.print("Bend: " + String(angle_2) + " degrees");
lcd.setCursor(0,2);

delay(500);
}

UKHeliBob · May 25, 2023, 3:38pm

Welcome to the forum

Why did you start a topic in the Uncategorised category of the forum when its description is

DO NOT CREATE TOPICS IN THIS CATEGORY

Your topic has been moved to the Programming category

kolaha · May 25, 2023, 3:46pm

arduino is not power source. connect LCD proper.

iulianapavel123 · May 25, 2023, 3:57pm

I moved it, it still doesn't work. the display is off and does not turn on

kolaha · May 25, 2023, 3:59pm

show

iulianapavel123 · May 25, 2023, 4:02pm

kolaha · May 25, 2023, 4:04pm

why you try to invent new combination of wrong connection?
you able to use ISP pins, they contain +5V and GND too.

iulianapavel123 · May 25, 2023, 4:15pm

I don't know what the pins are

iulianapavel123 · May 25, 2023, 4:33pm

what do I change in the code?

kolaha · May 25, 2023, 4:41pm

try that sketch now, with all current connections. is LCD still show proper ?
and if you want i look into your code - embed it as code.

iulianapavel123 · May 25, 2023, 4:58pm

it still doesn't work, the display stays on but doesn't show anything
`const int FLEX_PIN_1= A0; // Pin connected to voltage divider output
const int FLEX_PIN_2= A1; // Pin connected to voltage divider output

// Measure the voltage at 5V and the actual resistance of your
// 47k resistor, and enter them below:
const float VCC = 4.70; // Measured voltage of Ardunio 5V line
const float R_DIV_1 = 10000.0; // Measured resistance of 3.3k resistor
const float R_DIV_2 = 10000.0; // Measured resistance of 3.3k resistor

// Upload the code, then try to adjust these values to more
// accurately calculate bend degree.
const float STRAIGHT_RESISTANCE = 37300.0; // resistance when straight
const float BEND_RESISTANCE = 90000.0; // resistance at 90 deg
const int LCD_Vcc = 11;
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,16,2); // set the LCD address to 0x27 for a 16 chars and 2 line display

void setup()
{
lcd.begin(16, 2);
Serial.begin(9600);
pinMode(FLEX_PIN_1, INPUT);
pinMode(FLEX_PIN_2, INPUT);
pinMode(LCD_Vcc, OUTPUT);

 digitalWrite(11, HIGH);

}

void loop()
{
// Read the ADC, and calculate voltage and resistance from it
int flexADC_1 = analogRead(FLEX_PIN_1);
int flexADC_2 = analogRead(FLEX_PIN_2);
float flexV_1 = flexADC_1 * VCC / 1023.0;
float flexV_2 = flexADC_2 * VCC / 1023.0;
float flexR_1 = R_DIV_1 * (VCC / flexV_1 - 1.0);
float flexR_2 = R_DIV_2 * (VCC / flexV_2 - 1.0);
Serial.println("Resistance: " + String(flexR_1) + " ohms");
Serial.println("Resistance: " + String(flexR_2) + " ohms");
digitalWrite(LCD_Vcc, HIGH);
lcd.setCursor(0,0);

// Use the calculated resistance to estimate the sensor's
// bend angle:
float angle_1 = map(flexR_1, STRAIGHT_RESISTANCE, BEND_RESISTANCE,
0, 90.0);
Serial.println("Bend: " + String(angle_1) + " degrees");
Serial.println();
// bend angle:
float angle_2 = map(flexR_2, STRAIGHT_RESISTANCE, BEND_RESISTANCE,
0, 90.0);
Serial.println("Bend: " + String(angle_2) + " degrees");
Serial.println();
lcd.print("Bend: " + String(angle_1) + " degrees");
lcd.setCursor(2,1);
lcd.print("Bend: " + String(angle_2) + " degrees");
lcd.setCursor(0,2);

delay(500);
}`

kolaha · May 25, 2023, 5:12pm

go to ide, right click> point "copy for Forum"> left click
edit your post > delete everything > right click> point "paste"> left click

kolaha · May 25, 2023, 5:14pm

disconnect usb, connect usb, do you see one line full of blocks on LCD?

iulianapavel123 · May 25, 2023, 5:38pm


const int FLEX_PIN_1= A0; // Pin connected to voltage divider output
const int FLEX_PIN_2= A1; // Pin connected to voltage divider output

// Measure the voltage at 5V and the actual resistance of your
// 47k resistor, and enter them below:
const float VCC = 4.70; // Measured voltage of Ardunio 5V line
const float R_DIV_1 = 10000.0; // Measured resistance of 3.3k resistor
const float R_DIV_2 = 10000.0; // Measured resistance of 3.3k resistor

// Upload the code, then try to adjust these values to more
// accurately calculate bend degree.
const float STRAIGHT_RESISTANCE = 37300.0; // resistance when straight
const float BEND_RESISTANCE = 90000.0; // resistance at 90 deg
const int LCD_Vcc = 11;  
#include <Wire.h> 
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,16,2);  // set the LCD address to 0x27 for a 16 chars and 2 line display

void setup() 
{
   lcd.begin(16, 2);
  Serial.begin(9600);
  pinMode(FLEX_PIN_1, INPUT);
   pinMode(FLEX_PIN_2, INPUT);
    pinMode(LCD_Vcc, OUTPUT);
    
     digitalWrite(11, HIGH);
    
}

void loop() 
{
  // Read the ADC, and calculate voltage and resistance from it
  int flexADC_1 = analogRead(FLEX_PIN_1);
   int flexADC_2 = analogRead(FLEX_PIN_2);
  float flexV_1 = flexADC_1 * VCC / 1023.0;
   float flexV_2 = flexADC_2 * VCC / 1023.0;
  float flexR_1 = R_DIV_1 * (VCC / flexV_1 - 1.0);
  float flexR_2 = R_DIV_2 * (VCC / flexV_2 - 1.0);
  Serial.println("Resistance: " + String(flexR_1) + " ohms");
   Serial.println("Resistance: " + String(flexR_2) + " ohms");
     digitalWrite(LCD_Vcc, HIGH); 
   lcd.setCursor(0,0);    

  // Use the calculated resistance to estimate the sensor's
  // bend angle:
  float angle_1 = map(flexR_1, STRAIGHT_RESISTANCE, BEND_RESISTANCE,
                   0, 90.0);
  Serial.println("Bend: " + String(angle_1) + " degrees");
  Serial.println();
  // bend angle:
  float angle_2 = map(flexR_2, STRAIGHT_RESISTANCE, BEND_RESISTANCE,
                   0, 90.0);
  Serial.println("Bend: " + String(angle_2) + " degrees");
  Serial.println();
lcd.print("Bend: " + String(angle_1) + " degrees");
  lcd.setCursor(2,1);
  lcd.print("Bend: " + String(angle_2) + " degrees");
   lcd.setCursor(0,2);
  
  delay(500);
}

iulianapavel123 · May 25, 2023, 5:40pm

yes

kolaha · May 25, 2023, 6:55pm

lcd.init();

iulianapavel123 · May 26, 2023, 9:01am

Thank you! now it lights up and displays the LCD correctly, only it doesn't measure anything no matter how much I move the sensors and it only shows -63 degrees. do you think you could help me with this too?

iulianapavel123 · May 26, 2023, 9:11am

now it looks like this, but no matter how much I move the sensors, nothing changes

kolaha · May 26, 2023, 9:39am

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2); // set the LCD address to 0x27 for a 16 chars and 2 line display
const int FLEX_PIN_1 = A0; // Pin connected to voltage divider output
const int FLEX_PIN_2 = A1; // Pin connected to voltage divider output

void setup() {
  lcd.init();
}

void loop() {
  lcd.setCursor(0, 0);
  lcd.print(analogRead(FLEX_PIN_1));
  lcd.print("   ");
  lcd.setCursor(0, 1);
  lcd.print(analogRead(FLEX_PIN_2));
  lcd.print("   ");
  delay(200);
}

show schematic how you wired that sensors.

iulianapavel123 · May 26, 2023, 10:00am

black wires-gnd
white wires- , the signal -a1,10
and the brown wires are for 5v

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Flex sensors problem with arduino uno without breadboard

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