limit switches within a counter

Hi Paul,

Hopefully someone may respond sooner with better info (busy day for me today unfortunately for the next few hours, so this is a quick reply), but I had a few questions/suggestions:

1. What is the current symptom? Does any of it function, e.g. does LED turn on, does it stay on, etc. Does button detection work? Does the motor appear to get energised slightly?

2. Could you try powering the SNxxx chip from a separate supply, not from the Arduino board supply? To see what happens?

3. Could you place a 100uF capacitor across the supply rails close to the SNxxxx chip, and also a 100nF capacitor across the supply rails close to the chip too?

Hi Shabaz, thanks for getting back to me.

Firstly the LED goes on without the master button being pressed (currently playing about with that thinking it might be a pull up/pull down resistor issue).

from there my left/right limit buttons but its only working say 20%(which makes me think its more than just a button bouncing). then Even It doesnt seem to be responding that well to the button presses though - one works better than the other, but instead of this one button making it go say clockwise, it will do that, then change direction of motor a few times.

Even when i do get it to follow the left, then right commands it doesnt stop after my 5 loops. Infact the serial monitor is saying the 5 loops are completed before any buttons are even pressed which makes me thing ive set up the decisions from the flowchart wrong (im not sure which command to use instead as cant find anything online.)

Im now attempting to modify my original and more complex program by adding in the booleans and debouncing again    

here is my code:

/*

dancing toy System

*/

int MasterSwitchPin = 13;      // Master switch

int LeftSwitchPin = 12;        // Makes motor turn left

int RightSwitchPin = 8;        // Makes motor turn right

int Motor1APin = 7;            // H-bridge leg 1

int Motor2APin = 6;            // H-bridge leg 2

int LEDPin = 2;                // LED

boolean MasterlastButton = LOW;                

boolean MastercurrentButton = LOW;     

boolean MasterLEDon = false;

boolean LeftlastButton = LOW;                

boolean LeftcurrentButton = LOW;     

boolean Leftmotoron = false;

boolean RightlastButton = LOW;                

boolean RightcurrentButton = LOW;     

boolean Rightmotoron = false;

void setup()

{

  Serial.begin(9600);

  pinMode (MasterSwitchPin, INPUT);

  pinMode (LeftSwitchPin, INPUT);

  pinMode (RightSwitchPin, INPUT);

  pinMode (Motor1APin, OUTPUT);

  pinMode (Motor2APin, OUTPUT);

  pinMode (LEDPin, OUTPUT);

}

boolean Masterdebounce(boolean last)           

{

        boolean current = digitalRead(MasterSwitchPin);

         if (last != current)                   

{

delay(5);             

current = digitalRead(MasterSwitchPin);     

}

return current;       

}

boolean Leftdebounce(boolean last)           

{

        boolean current = digitalRead(LeftSwitchPin);

         if (last != current)                   

{

delay(5);             

current = digitalRead(LeftSwitchPin);     

}

return current;       

}

boolean Rightdebounce(boolean last)           

{

        boolean current = digitalRead(RightSwitchPin);

         if (last != current)                   

{

delay(5);             

current = digitalRead(RightSwitchPin);     

}

return current;       

}

void loop()

{

  MastercurrentButton = Masterdebounce(MasterlastButton);

  LeftcurrentButton = Leftdebounce(LeftlastButton);

  RightcurrentButton = Rightdebounce(RightlastButton);

   Serial.print("starting");

   if (digitalRead(MasterSwitchPin) == HIGH && MasterlastButton == LOW)

     {

       MasterLEDon = !MasterLEDon;

       digitalWrite(LEDPin, HIGH);

       Serial.print("button pressed LED on");

for (int counter = 1 ; counter <= 5; counter = counter +1) 

   { 

    while (digitalRead(LeftSwitchPin) == HIGH && LeftlastButton == LOW)

      {

        Leftmotoron = !Leftmotoron;

        Rightmotoron = !Rightmotoron;

      digitalWrite(Motor1APin, HIGH);

      digitalWrite(Motor2APin, LOW);

      Serial.print("motor goes one way");

      }      

      delay(1000);

    while (digitalRead(RightSwitchPin) == HIGH && RightlastButton == LOW)

      {

        Leftmotoron = !Leftmotoron;

        Rightmotoron = !Rightmotoron;

      digitalWrite(Motor1APin, LOW);

      digitalWrite(Motor2APin, HIGH);

      Serial.print("motor goes the other wat way");

      }

  delay(1000);     

   }

   Serial.print("repeated 5 times");

       digitalWrite(LEDPin, LOW);

       digitalWrite(Motor1APin, LOW);

       digitalWrite(Motor2APin, LOW);

       Serial.print("switch everything off");

}

}

all this does though is switch my LED off when the master button is pressed (LED goes on as soon as sketch is uploaded) and none of the motor controls work.

Hi Paul,

I don't think any debouncing is needed, so the first code is more usable I think. I modified it slightly (created #define to clean it up, and rearranged the location of code so the loops are a bit cleaner):

/*
dancing toy System
*/

int MasterSwitchPin = 13;      // Master switch
int LeftSwitchPin = 12;        // Makes motor turn left
int RightSwitchPin = 8;        // Makes motor turn right
int Motor1APin = 7;            // H-bridge leg 1
int Motor2APin = 6;            // H-bridge leg 2
int LEDPin = 2;                // LED


#define LED_ON digitalWrite(LEDPin, LOW)
#define LED_OFF digitalWrite(LEDPin, HIGH)


#define MOTOR_LEFT digitalWrite(Motor2APin, LOW);digitalWrite(Motor1APin, HIGH)
#define MOTOR_RIGHT digitalWrite(Motor1APin, LOW);digitalWrite(Motor2APin, HIGH)
#define MOTOR_STOP digitalWrite(Motor1APin, LOW);digitalWrite(Motor2APin, LOW)


#define BUTTON_PRESSED (digitalRead(MasterSwitchPin) == HIGH)
#define END1_HIT (digitalRead(LeftSwitchPin) == HIGH)
#define END2_HIT (digitalRead(RightSwitchPin) == HIGH)

void setup()
{
  Serial.begin(9600);
  pinMode (MasterSwitchPin, INPUT);
  pinMode (LeftSwitchPin, INPUT);
  pinMode (RightSwitchPin, INPUT);
  pinMode (Motor1APin, OUTPUT);
  pinMode (Motor2APin, OUTPUT);
  pinMode (LEDPin, OUTPUT);
}

void loop()
{
  LED_OFF;
  while(!BUTTON_PRESSED); // wait here until the button is pressed
  LED_ON;
  Serial.print("button pressed LED on");
  for (int counter = 1 ; counter <= 5; counter = counter +1)
  {
    MOTOR_LEFT;
    Serial.print("motor goes one way");
    while (!END1_HIT)
    {
    // do nothing, just delay a very tiny amount
    delay(10);
    }
   MOTOR_STOP;   
    delay(1000);
  
    MOTOR_RIGHT;
    Serial.print("motor goes the other way");
    while (!END2_HIT)
    {
      // do nothing, just delay a very tiny amount
    delay(10);
    }
    MOTOR_STOP;
    delay(1000);   
  } // end of for loop

  Serial.print("repeated 5 times");
}

I have no idea if the code will work (I don't have an Arduino) but I suspect it is closer to what is needed. Could you give it a test, or at least test a modified version of this, so that you can confirm the #define lines do what is expected, and then the program logic can be ironed out.

The exclamation marks indicate boolean NOT by the way.

Also, I'm not sure the circuit is correct. I think pin 1 of that integrated circuit needs to go somewhere - can you connect it to the positive supply?

Also, the LED is connected with one end to +ve according to your diagram, so by default the LED would be lit if the output is LOW. I've taken that into account in the code, so that the #define LED_ON writes LOW to the pin, and LED_OFF writes HIGH to the pin.

Also, it is fairly mandatory to have a large-ish capacitor (maybe 100uF) and a 100nF capacitor across the supply rails very close to the motor control IC, i.e. directly near pin 4 and pin 8.

Finally, your motor controller may be causing effects to the supply rail, causing unexpected behaviour from the Arduino. To eliminate that during testing, you need a separate supply for the motor controller (i.e. disconnect pins 8 and 16 of the IC, and feed a separate battery +ve supply to those pins, and connect the battery -ve to the ground.

EDIT: corrected a few things in the code and text.

I like what you did with this

Just a slight improvement can be done by extending your approach to defines, it wont make a huge difference in this code but as a practice it is a good habit to get into

#define MasterSwitchPin   13       // Master switch 
#define LeftSwitchPin   12         // Makes motor turn left 
#define RightSwitchPin   8         // Makes motor turn right 
#define Motor1APin   7             // H-bridge leg 1 
#define Motor2APin   6             // H-bridge leg 2 
#define LEDPin   2                 // LED

this way it saves more memory and eliminates type and additional code to copy from the INT variable at tun time

I like what you did with this

Just a slight improvement can be done by extending your approach to defines, it wont make a huge difference in this code but as a practice it is a good habit to get into

#define MasterSwitchPin   13       // Master switch 
#define LeftSwitchPin   12         // Makes motor turn left 
#define RightSwitchPin   8         // Makes motor turn right 
#define Motor1APin   7             // H-bridge leg 1 
#define Motor2APin   6             // H-bridge leg 2 
#define LEDPin   2                 // LED

this way it saves more memory and eliminates type and additional code to copy from the INT variable at tun time

Hi Peter,

You're right, much better practice to rip out those 'int's in the code too into #defines.

Basically something like

#define MASTER_SWITCH_PIN 13

etc..

(the '=' and '// xyz comment' need to be removed) - I also like capitalizing all #defines, just so they are clear they are not variables.

the "=" are gone, you must have read it the moment I posted and did not see the almost immediate correction

the comments are actually legal there and should not be discouraged, though appropriate names of the defines should make it clear what they do and as they take no final memory space should not need to be abbreviated so if the names are obvious then you could choose to drop the comments. Unless you need to express perhaps reasonable limits for the value of the define or something

I agree with the capitalization of the defines in order to easily identify them from variables

Peter