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[on:]

Hey Guys, Basically I have an Arduino UNO, a 20x4 LCD screen, 4 push buttons and some temp sensors.

Now this project is going  in my car to show battery voltages and a few temps.

I had the idea of pushing one button and all my voltages will show, (input via an analog input - 22k resistor on the neg, 68k on the pos)
I have attached code for that bit.

Now I just cant Figure out how to tell the audrino to switch what it displays once a button is pushed.

(to show the arduino what button is pushed I have 5V going into the push-buttons, Then each has its own different value of restance. I used this code to see what each value was.)
int sensePin =0;

void setup(){
  analogReference(DEFAULT);
 
 Serial.begin(9600);
}

void loop (){
  Serial.println(analogRead(sensePin));
delay(500);
}

When button 2 is pushed I would like the temps to show, I have Dallas 1 wire digital temp sensors (ill ask about them later)

So My question is how can i tell the Arduino to swap what it displays?

Thanks a heap guys.

[Reply #1 on:]

Something like this

Code:

const int sensePin = A0;

void setup(){
    Serial.begin(9600);
}

void loop (){
    int buttonValue = analogRead(sensePin); // buttonValue should be between 0 and 1023
    int displayMode = -1;   // Assume no change in display mode
    if (buttonValue > 1000) {
        displayMode = 3;
    }
    if (buttonValue > 700) {
        displayMode = 2;
    }
    if (buttonValue > 400) {
        displayMode = 1;
    }
    if (buttonValue > 100) {
        displayMode = 0;
    }
    Serial.print(buttonValue);
    Serial.print(" = ");
    Serial.println(displayMode);
    delay(500);
}

You would need to adjust the values to suit your buttons.

[Reply #2 on:]

If you have the inputs, I would just run each button to a seperate pin.  If you want to use an analog read, look at getting a rotary or other multi-position switch - that way you can't have more than one button pressed at a time, and you (shouldn't) need to debounce.

For the multi-input, store which pin was pushed, and run a switch statement.

For the rotary or multi-position switch, something similar to Riva's code should work.

[Reply #3 on:]

Thanks, Where do i specify to The Ardunino what code is connected to each display mode.

[Reply #4 on:]

Thanks, Where do i specify to The Ardunino what code is connected to each display mode.

After the code I wrote you have a variable called displayMode that will be the desired display mode required or -1 if no button pressed. Just use something like a switch case http://arduino.cc/en/Reference/SwitchCase to act out the desired mode.

[Reply #5 on:]

Hey, Ive had a good try at it, hows it look? I'm getting an Error saying " error: expected initializer before 'if' "
On this line.
if (val == val2) { // make sure we got 2 consistant readings!

#include <LiquidCrystal.h> //import the Class for the LCD
LiquidCrystal lcd(12, 11, 5, 4, 3, 2); //pin numbers for the LCD

int switchPin = 0; // Select button is connected to pin 0
int val; // variable for reading the pin status
int val2; // variable for reading the delayed status
int buttonState; // variable to hold the select button state
int DisplayMode = 0; // Display Mode

int primary_battPin = 1; // Input from primary Battery
int secondary_battPin = 2; // Input from secondary Battery
int primary_val = 0; //temporarily store the primary input
int secondary_val = 0; //temporarily store the secondary input

float primary_pinVoltage = 0; // variable to hold the calculated voltage
float secondary_pinVoltage = 0; // variable to hold the calculated voltage
float primary_batteryVoltage = 0; //Temporarily store the primary Voltage
float secondary_batteryVoltage = 0; //Temporarily store the secondary Voltage

float ratio = 4.039; // The multiplier depending on which resistors used
// I used 68K and 22K 1/2 watt resistors.
void setup()
{
pinMode(switchPin, INPUT); // Set the switch pin as input
buttonState = digitalRead(switchPin); // read the initial state
lcd.begin(20, 4); // initialise the LCD screen (20 characters long, by 4 lines high)
}

void loop()


if (val == val2) { // make sure we got 2 consistant readings!
if (val != buttonState) { // the button state has changed!
if (val == LOW) { // check if the button is pressed
if (DisplayMode == 0) {DisplayMode = 1;} // Change to Mode 1
else {
if (DisplayMode == 1) {DisplayMode = 2;} // Change to Mode 2
else {
if (DisplayMode == 2) {DisplayMode = 3;} // Change to Mode 3
else {
if (DisplayMode == 3) {DisplayMode = 0;} // Change to Mode 0


if (value > (750) {
   screen(1);
} else if (value > 550) {
   screen(2);
} else if (value > 410) {
   screen(3);
} else if (value > 340) {
   screen(4);
} else if (value > 300) {
   screen(5);
}




}}}}}}
buttonState = val; // save the new state in our variable

// Now do whatever the DisplayMode Choosen


if (DisplayMode == 0) { // Battery Monitor Selection
primary_val = analogRead(primary_battPin); //Read the primary Battery input per loop
secondary_val = analogRead(secondary_battPin); //Read the secondary Battery input per loop

primary_pinVoltage = primary_val * 0.00488; //0.00488mV per 1024 steps for 5 Volts (ie; 5 / 1024 = 0.00488)
secondary_pinVoltage = secondary_val * 0.00488;
primary_batteryVoltage = primary_pinVoltage * ratio; //grab the calculated under 5Volt input and multiply it by the ratio to ..........
secondary_batteryVoltage = secondary_pinVoltage * ratio; // .............take it back to the 11~12~13Volt Range.

;lcd.setCursor(0, 0);// Place the Cursor on the Fist line first character position on the LCD screen
;lcd.print ("Batteries:")// Heading
;lcd.setCursor(0, 1);    // First Line
;lcd.print("Primary  : "); // Second Line
;lcd.print(primary_batteryVoltage); //The Voltage of Primary Battery.. S
;lcd.setCursor(0, 2);// Place the Cursor on the Second line first character position on the LCD screen
;lcd.print("Secondary: "); // Third Line
;lcd.print(secondary_batteryVoltage); //The Voltage of Secondary Battery.

delay(2000); //Pause for two seconds
}
if (DisplayMode == 1) { // Tempreture Selection
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Air Temp : ");
// Air Temp Workings
lcd.print(" C");
lcd.setCursor(0, 1);
lcd.print("Water Temp : ");
// Water Temp Workings
lcd.print(" C");
delay(2000);
}

if (DisplayMode == 2) { // Spare 1 Selection
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Spare 1-1 : ");
// Spare 1-1 Workings
lcd.print(" ?");
lcd.setCursor(0, 1);
lcd.print("Spare 1-2 : ");
// Temp2
lcd.print(" ?");
delay(2000);
}

if (DisplayMode == 3) { // Spare 2 Selection
lcd.clear();
lcd.setCursor(0, 0);
lcd.print("Spare 2-1 : ");
// Spare 2-1 Workings
lcd.print(" ?");
lcd.setCursor(0, 1);
lcd.print("Spare 2-2 : ");
// Spare 2-2 Workings
lcd.print(" ?");
delay(2000);
}
}

Thank you.

[Reply #6 on:]

Several problems with your code I'm sorry to say.
You have several variables that are either not declared or not used (value, screen, val2 + many more)
You read the button state in setup but no more after that in loop so no amount of button pressing will do anything.
You have changed to using a digital pin (initial problem was analogue) but still have code to work with analogue pins.
Assuming this is the full code I can see now you will need to think about using a different structure (see BlinkWithoutDelay example) else the button press will be very unresponsive (button reading and long delays don't work well together)

I have attached the core of how your program could/should work and you just need to add in your display code where needed.

Code:

const int switchPin = 2;                  // Select button is connected to pin 2
const long refreshDelay = 2000;           // Duration between display updates

byte displayMode = 0;                     //Default display mode

void setup() {
  pinMode(switchPin, INPUT);              // Set the switch pin as input
}

void loop(){
  long currentTime = millis();            // Get current time
 
  while ((millis() - currentTime) < refreshDelay){
    if (digitalRead(switchPin) == HIGH) { // Alter HIGH/LOW depending on how switch is wired
      displayMode++;                      // Increment display mode
      if (displayMode > 2) {              // Reset display mode if beyond max mode
        displayMode = 0;
      }
      break;                              // Exit while loop early as button pressed
    }
   
    switch (displayMode) {
      case 0:
      // Put display mode 0 code here
      break;
      case 1:
      // Put display mode 1 code here
      break;
      case 2:
      // Put display mode 2 code here
      break;
    }
  }
}

[Reply #7 on:]

Thank you so much for your help!
With the digital & analog pins, I'm using the Analog pins. Pin 0 is the input for the buttons. So does this mean I can just go

Code:

const int switchPin = 0; 

Or Because it says;

Code:

while ((millis() - currentTime) < refreshDelay){
    if (digitalRead(switchPin) == HIGH)

I should find an available Digital pin.


Not sure if I mentioned the button set up im going for is a voltage divider type set up so all 4 buttons goto the one pin. I have obtained each value each button sends to the Arduino

0- 890
1- 695
2- 363
3- 318


Now sorry for being such a pest Im really trying my best to understand all this, I just copied and pasted some of the old code in.

Code:

// include the library code:
#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

int DisplayMode = 0; // Display Mode

int primary_battPin = 1; // Input from primary Battery
int secondary_battPin = 2; // Input from secondary Battery
int primary_val = 0; //temporarily store the primary input
int secondary_val = 0; //temporarily store the secondary input

float primary_pinVoltage = 0; // variable to hold the calculated voltage
float secondary_pinVoltage = 0; // variable to hold the calculated voltage
float primary_batteryVoltage = 0; //Temporarily store the primary Voltage
float secondary_batteryVoltage = 0; //Temporarily store the secondary Voltage

float ratio = 4.039; // The multiplier depending on which resistors used
// I used 68K and 22K 1/2 watt resistors.

const int switchPin = 6;                  // Select button is connected to pin 2
const long refreshDelay = 2000;           // Duration between display updates

byte displayMode = 0;                     //Default display mode

void setup() {
  pinMode(switchPin, INPUT);              // Set the switch pin as input
}

void loop(){
  long currentTime = millis();            // Get current time
 
  while ((millis() - currentTime) < refreshDelay){
    if (digitalRead(switchPin) == HIGH) { // Alter HIGH/LOW depending on how switch is wired
      displayMode++;                      // Increment display mode
      if (displayMode > 2) {              // Reset display mode if beyond max mode
        displayMode = 0;
      }
      break;                              // Exit while loop early as button pressed
    }
   
    switch (displayMode) {
      case 0:
    if (DisplayMode == 0) { // Battery Monitor Selection
primary_val = analogRead(primary_battPin); //Read the primary Battery input per loop
secondary_val = analogRead(secondary_battPin); //Read the secondary Battery input per loop

primary_pinVoltage = primary_val * 0.00488; //0.00488mV per 1024 steps for 5 Volts (ie; 5 / 1024 = 0.00488)
secondary_pinVoltage = secondary_val * 0.00488;
primary_batteryVoltage = primary_pinVoltage * ratio; //grab the calculated under 5Volt input and multiply it by the ratio to ..........
secondary_batteryVoltage = secondary_pinVoltage * ratio; // .............take it back to the 11~12~13Volt Range.

;lcd.setCursor(0, 0);// Place the Cursor on the Fist line first character position on the LCD screen
;lcd.print ("Batteries:")// Heading
;lcd.setCursor(0, 1);    // First Line
;lcd.print("Primary  : "); // Second Line
;lcd.print(primary_batteryVoltage); //The Voltage of Primary Battery.. S
;lcd.setCursor(0, 2);// Place the Cursor on the Second line first character position on the LCD screen
;lcd.print("Secondary: "); // Third Line
;lcd.print(secondary_batteryVoltage); //The Voltage of Secondary Battery.

delay(2000); //Pause for two seconds
}
      break;
      case 1:
      // Put display mode 1 code here
      break;
      case 2:
      // Put display mode 2 code here
      break;
    }
  }
}

Thanks for your Input

[Reply #8 on:]

At least one of us us getting confused as original post and example code used analogRead but the next version you sent used digital (buttonState = digitalRead(switchPin); // read the initial state)

Not sure if I mentioned the button set up im going for is a voltage divider type set up so all 4 buttons goto the one pin. I have obtained each value each button sends to the Arduino

0- 890
1- 695
2- 363
3- 318

What value do you get with no button pressed, is it 0 or 1023 as this will effect the below code.

Code:

const int switchPin = A0;                 // Select button is connected to pin
const long refreshDelay = 2000;           // Duration between display updates

byte displayMode = 0;                     //Default display mode
byte oldDisplayMode = 0;                  //Old display mode

void setup() {
  pinMode(switchPin, INPUT);              // Set the switch pin as input
}

void loop(){
  long currentTime = millis();            // Get current time
 
  while ((millis() - currentTime) < refreshDelay){
    int buttonValue = analogRead(switchPin); // buttonValue should be between 0 and 1023
    if (buttonValue > 792) {
      displayMode = 0;
    }
    if (buttonValue > 529) {
      displayMode = 1;
    }
    if (buttonValue > 340) {
      displayMode = 2;
    }
    if (buttonValue > 159) {
      displayMode = 3;
    }
    if (displayMode != oldDisplayMode) {  // Has display mode changed?
      oldDisplayMode = displayMode;
      break;                              // Exit while loop early as button pressed
    }
  }
 
  switch (displayMode) {
    case 0:
    // Put display mode 0 code here
    break;
    case 1:
    // Put display mode 1 code here
    break;
    case 2:
    // Put display mode 2 code here
    break;
    case 3:
    // Put display mode 3 code here
    break;
  }
 }

This code will not work as is as you need to know what value is returned for no button pressed. I'm also not able to test it as I'm at work (no arduino here)

[Reply #9 on:]

Hey,

What value do you get with no button pressed, is it 0 or 1023 as this will effect the below code.

I'm getting 0.

I'm sorry for the confusion, I had 2 versions of this going (mistake as it lead to so much confusion) I think  Ill make the input pin an analog one.

This is what I have at the minute and Ive uploaded it to the Arduino.

Code:

#include <LiquidCrystal.h> //import the Class for the LCD
LiquidCrystal lcd(12, 11, 5, 4, 3, 2); //pin numbers for the LCD

const int switchPin = A0;                 // Select button is connected to pin
const long refreshDelay = 2000;           // Duration between display updates

byte displayMode = 0;                     //Default display mode
byte oldDisplayMode = 0;                  //Old display mode
byte buttonValue = 0;

int val; // variable for reading the pin status
int val2; // variable for reading the delayed status
int primary_battPin = 1; // Input from primary Battery
int secondary_battPin = 2; // Input from secondary Battery
int primary_val = 0; //temporarily store the primary input
int secondary_val = 0; //temporarily store the secondary input

float primary_pinVoltage = 0; // variable to hold the calculated voltage
float secondary_pinVoltage = 0; // variable to hold the calculated voltage
float primary_batteryVoltage = 0; //Temporarily store the primary Voltage
float secondary_batteryVoltage = 0; //Temporarily store the secondary Voltage

float ratio = 4.039; // The multiplier depending on which resistors used
// I used 68K and 22K 1/2 watt resistors.

void setup() {
  pinMode(switchPin, INPUT);              // Set the switch pin as input
}

void loop(){
  long currentTime = millis();            // Get current time
 
  while ((millis() - currentTime) < refreshDelay){
    int buttonValue = analogRead(switchPin); // buttonValue should be between 0 and 1023
    if (buttonValue > 792) {
      displayMode = 0;
    }
    if (buttonValue > 529) {
      displayMode = 1;
    }
    if (buttonValue > 340) {
      displayMode = 2;
    }
    if (buttonValue > 159) {
      displayMode = 3;
    }
    if (displayMode != oldDisplayMode) {  // Has display mode changed?
      oldDisplayMode = displayMode;
      break;                              // Exit while loop early as button pressed
    }
  }
 
  switch (displayMode) {
    case 0:
primary_val = analogRead(primary_battPin); //Read the primary Battery input per loop
secondary_val = analogRead(secondary_battPin); //Read the secondary Battery input per loop

primary_pinVoltage = primary_val * 0.00488; //0.00488mV per 1024 steps for 5 Volts (ie; 5 / 1024 = 0.00488)
secondary_pinVoltage = secondary_val * 0.00488;
primary_batteryVoltage = primary_pinVoltage * ratio; //grab the calculated under 5Volt input and multiply it by the ratio to ..........
secondary_batteryVoltage = secondary_pinVoltage * ratio; // .............take it back to the 11~12~13Volt Range.

;lcd.setCursor(0, 0);// Place the Cursor on the Fist line first character position on the LCD screen
;lcd.print ("Batteries:")// Heading
;lcd.setCursor(0, 1);    // First Line
;lcd.print("Primary  : "); // Second Line
;lcd.print(primary_batteryVoltage); //The Voltage of Primary Battery.. S
;lcd.setCursor(0, 2);// Place the Cursor on the Second line first character position on the LCD screen
;lcd.print("Secondary: "); // Third Line
;lcd.print(secondary_batteryVoltage); //The Voltage of Secondary Battery.

delay(2000); //Pause for two seconds
 break;
    case 1:
    // Put display mode 1 code here
    break;
    case 2:
    // Put display mode 2 code here
    break;
    case 3:
    // Put display mode 3 code here
    break;
  }
 }

Now When I push the button that send the value 890 To pin A0..... Nothing happens

I cant believe how Frustrating this is, Maybe ive tried a project that's beyond my level of coding ability,:(

[Reply #10 on:]

Now When I push the button that send the value 890 To pin A0..... Nothing happens smiley-sad
I cant believe how Frustrating this is, Maybe ive tried a project that's beyond my level of coding ability,:(

More likely it's beyond my ability
I was cascading the button reading the wrong way so it was always coming out as mode 3
Try this.

Code:

#include <LiquidCrystal.h> //import the Class for the LCD
LiquidCrystal lcd(12, 11, 5, 4, 3, 2); //pin numbers for the LCD

const int switchPin = A0;                       // Select button is connected to pin
const long refreshDelay = 2000;                 // Duration between display updates

byte oldDisplayMode = 0;                        // Old display mode

int val; // variable for reading the pin status
int val2; // variable for reading the delayed status
int primary_battPin = 1; // Input from primary Battery
int secondary_battPin = 2; // Input from secondary Battery
int primary_val = 0; //temporarily store the primary input
int secondary_val = 0; //temporarily store the secondary input

float primary_pinVoltage = 0; // variable to hold the calculated voltage
float secondary_pinVoltage = 0; // variable to hold the calculated voltage
float primary_batteryVoltage = 0; //Temporarily store the primary Voltage
float secondary_batteryVoltage = 0; //Temporarily store the secondary Voltage

float ratio = 4.039; // The multiplier depending on which resistors used
// I used 68K and 22K 1/2 watt resistors.

void setup() {
    pinMode(switchPin, INPUT);                      // Set the switch pin as input
}

void loop(){
    long currentTime = millis();                    // Get current time
   
    while ((millis() - currentTime) < refreshDelay){
        int buttonValue = analogRead(switchPin);    // buttonValue should be between 0 and 1023
        byte displayMode = -1;                      // Assume no change in display mode
        if (buttonValue > 159) {
            displayMode = 3;
        }
        if (buttonValue > 340) {
            displayMode = 2;
        }
        if (buttonValue > 529) {
            displayMode = 1;
        }
        if (buttonValue > 792) {
            displayMode = 0;
        }
        if (displayMode != -1) {                    // Was button pressed?
            if (displayMode != oldDisplayMode) {    // Has display mode changed?
                oldDisplayMode = displayMode;       // Set new display mode
                break;                              // Exit while loop early as button pressed
            }
        }
    }
   
    switch (oldDisplayMode) {
        case 0:
            primary_val = analogRead(primary_battPin); //Read the primary Battery input per loop
            secondary_val = analogRead(secondary_battPin); //Read the secondary Battery input per loop
           
            primary_pinVoltage = primary_val * 0.00488; //0.00488mV per 1024 steps for 5 Volts (ie; 5 / 1024 = 0.00488)
            secondary_pinVoltage = secondary_val * 0.00488;
            primary_batteryVoltage = primary_pinVoltage * ratio; //grab the calculated under 5Volt input and multiply it by the ratio to ..........
            secondary_batteryVoltage = secondary_pinVoltage * ratio; // .............take it back to the 11~12~13Volt Range.
           
            lcd.setCursor(0, 0);// Place the Cursor on the Fist line first character position on the LCD screen
            lcd.print ("Batteries:");// Heading
            lcd.setCursor(0, 1);    // First Line
            lcd.print("Primary  : "); // Second Line
            lcd.print(primary_batteryVoltage); //The Voltage of Primary Battery.. S
            lcd.setCursor(0, 2);// Place the Cursor on the Second line first character position on the LCD screen
            lcd.print("Secondary: "); // Third Line
            lcd.print(secondary_batteryVoltage); //The Voltage of Secondary Battery.
            break;
        case 1:
        // Put display mode 1 code here
        break;
        case 2:
        // Put display mode 2 code here
        break;
        case 3:
        // Put display mode 3 code here
        break;
    }
}

[Reply #11 on:]

I cant thank you enough!!!

It well on the way, Now yet another problem but im hoping  its an easy fix,

Now when I press the button, the screen only reads, Secondary: (insert voltage)
Not the other bits like it should.

Now Ive double checked and the screen does work with this code

Code:

// include the library code:
#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

void setup() {
  // set up the LCD's number of columns and rows:
  lcd.begin(20, 4);
  // Print a message to the LCD.
  lcd.print("hello, world!");
}

void loop() {
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  lcd.print(millis()/1000);
}

(I have made sure every line works)
Ideas on that one, It has to be in the code somewhere

[Reply #12 on:]

I found the problem!!!
I forgot to tell the Arduino how Big the screen was

Code:

lcd.begin(20, 4);

.

Now Im onto my next adventure, The temp sensors
Ill post what im come up with here, Probally tomorrow its getting late here is Australia!

Riva, Thank you so much for your help !!!

[Reply #13 on:]

Riva, Thank you so much for your help !!!

No problem 

[Reply #14 on:]

Despite my tired eyes i want to get a little more done.

Now as i press the button the values change, This is all good until I release then all values freeze, Is there a way to make it keep reading without holding the button in or just change switch types?

2- Not Really a big thing, but when i turn the Arduino on, its just a blank screen until i press a button, In this section is it possible to put a message in, I tried putting it in a few spots but It didn't work properly , IE- the text i put in never went away.

Maybe just wire a resistor in so on start it gives a high value and then put that in the code?