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### Topic: Binary counting using 12 LEDs (Read 19697 times)previous topic - next topic

#### littlewolf

##### Mar 12, 2013, 08:14 pmLast Edit: Mar 16, 2013, 10:05 am by littlewolf Reason: 1
Hi guys,
I am currently working on a new project but, like always, I am a bit
struggling with the code.
My project include 12 LEDs connected to an Arduino Mega and a 4/3 keypad.
I would like to do binary counting using the LEDs and to change the rate of
increase or decrease using the keypad.
For example, by pressing 1 and "i++" or "i--"(I changed the "*" and "#" characters)
to either increase or decrease the counting by one.
Similarly, by pressing any other character, to either increase or decrease the counting
by its value.

Here is my code so far:

Code: [Select]
`/* Binary counting using 12 LEDs and a keypad to change the increasing or decreasing rate */#include <Keypad.h>int i;int ledPin[12]={13,12,11,10,9,8,7,6,5,4,3,2};int counter;const byte ROWS = 4; //four rowsconst byte COLS = 3; //three columnschar keys[ROWS][COLS] = { {'1','2','3'}, {'4','5','6'}, {'7','8','9'}, {'i--','10','i++'} };/* I want to use i-- and i++ to either increaseor decrease the binary counting */byte rowPins[ROWS] = {31, 33, 35, 37}; //connect to the row pinouts of the keypadbyte colPins[COLS] = {39, 41, 43}; //connect to the column pinouts of the keypad Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );void setup(){      for(i=0; i<12; i++){  pinMode(ledPin[i], OUTPUT);      // sets the digital pins as output    char key = keypad.getKey();   if (key=1) {   counter = i+1 } else if(key=2) {   counter= i+2 } else if(key=3) { counter=i+3 } else if etc....      }}`

Could you help?
Regards

#### HazardsMind

#1
##### Mar 12, 2013, 08:24 pm
Quote
{'i--','10','i++'}

It doesn't work like that. You should have an IF statement look for '*' or '#' and change the counter accordingly.

Quote
key=1,key=2,key=3

Again, it does not work like that. If anything, it should be if(key == '1'), if(key == '2') and so on.

Now you want to look at the keypad press a number and then decide whether it should be incremented or decremented? Ok well then you need to have if so that if a key is pressed, it then looks at another incoming key and see if it is '#' or '*'. So your looking at an IF within an IF statement.
My GitHub:
https://github.com/AndrewMascolo?tab=repositories

#### littlewolf

#2
##### Mar 12, 2013, 09:42 pmLast Edit: Mar 13, 2013, 12:33 am by littlewolf Reason: 1
Something like this ...?
Code: [Select]
`/* Binary counting using 12 LEDs and a keypad to change the increasing or decreasing rate */#include <Keypad.h>int i;int ledPin[12]={13,12,11,10,9,8,7,6,5,4,3,2};int counter;const byte ROWS = 4; //four rowsconst byte COLS = 3; //three columnschar keys[ROWS][COLS] = { {'1','2','3'}, {'4','5','6'}, {'7','8','9'}, {'*','0','#'} };/* I want to use i-- and i++ to either increaseor decrease the binary counting */byte rowPins[ROWS] = {31, 33, 35, 37}; //connect to the row pinouts of the keypadbyte colPins[COLS] = {39, 41, 43}; //connect to the column pinouts of the keypad Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );void setup(){      for(i=0; i<12; i++){  pinMode(ledPin[i], OUTPUT);      // sets the digital pins as output    char key = keypad.getKey();   if (key==1) {   if (key==*){     counter=i+1 /* start counting up by 1 */   } else if (key==-)   {     counter=i-1 /*etc  */   } } else if(key==2) {   if (key==*){     counter=i+2   } else if (key==-)   {     counter=i-2   } } else if(key==3) { counter=i+3 } else if etc....      }}`
I'm not sure how to write the counter function.

#### MarkT

#3
##### Mar 12, 2013, 09:53 pm
character constants always have single quotes, so
Code: [Select]
` if (key==1)`
needs to be
Code: [Select]
` if (key=='1')`
and so on - the result of getKey() is one of the characters you put in the array so its a character code,
and the code for '1' is not 1.  Put another way '1' denotes the character code used, you never
need to see it or even know that its actually 49.

And if you are comparing the same integer or character variable against a set of possibilities then the
switch statement is much neater:
Code: [Select]
`  switch (key)  {  case '1': .....    break ;  case '*': ....    break ;  ......  }`
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

#### lloyddean

#4
##### Mar 12, 2013, 10:36 pm
Code: [Select]
` if (key==1) {   if (key==*){     counter=i+1 /* start counting up by 1 */   } else if (key==-)`

If key equals '1' then it very well can't be '*' at the next 'if'

#### HazardsMind

#5
##### Mar 12, 2013, 11:07 pm

Code: [Select]
` if (key==1) {   if (key==*){     counter=i+1 /* start counting up by 1 */   } else if (key==-)`

If key equals '1' then it very well can't be '*' at the next 'if'

That's why you read the key again. Also why is this not in the loop()?
My GitHub:
https://github.com/AndrewMascolo?tab=repositories

#### littlewolf

#6
##### Mar 13, 2013, 12:31 am
Code: [Select]
`/* Binary counting using 12 LEDs and a keypad to change the increasing or decreasing rate */#include <Keypad.h>int i;int x;int ledPin[12]={13,12,11,10,9,8,7,6,5,4,3,2};int counter;const byte ROWS = 4; //four rowsconst byte COLS = 3; //three columnschar keys[ROWS][COLS] = { {'1','2','3'}, {'4','5','6'}, {'7','8','9'}, {'*','0','#'} };/* I want to use i-- and i++ to either increaseor decrease the binary counting */byte rowPins[ROWS] = {31, 33, 35, 37}; //connect to the row pinouts of the keypadbyte colPins[COLS] = {39, 41, 43}; //connect to the column pinouts of the keypad Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );void setup(){  Serial.begin(9600);   for(i=0; i<12; i++){  pinMode(ledPin[i], OUTPUT);      // sets the digital pins as output  }void loop(){    char key = keypad.getKey();    if (key=='1') {   /* getKey for case A and case B   case A = increment   case B = decrement   */ } else if(key=='2') {    } else if(key=='3') { } else if(key=='4') {  } else if(key=='5') {  } else if(key=='6') {    } else if(key=='7') {    } else if(key=='8') {    } else if(key=='9') {    } else if(key=='0') {    }}`
Hope it looks better although it still has errors.
Now I have to figure out how to do the counting

#### littlewolf

#7
##### Mar 13, 2013, 04:50 pm
There is an easier way to write this code by using "digitalWrite" but this
will result in a very long and boring code.
I'm not sure yet how this keypad will control  the binary counting.
Perhaps an attachInterrupt() might be needed to shift the code to a new loop.
I tried this with one switch only in order to control the LEDs but I wasn't able
to change "digitalWrite" into a counting loop.
I couldn't find any example on the internet of how to control a binary counting
using switches and I am a bit confused.

As you can see, I need your help.

Regards

#### HazardsMind

#8
##### Mar 13, 2013, 04:59 pm
Try this.
Look at the key, if it is not '#' or '*' then store it in a variable, convert that variable to an int, and then wait for the key to be '#' or '*'. Once key is '#' or '*', the code will decide whether to make it + or - the counter.
My GitHub:
https://github.com/AndrewMascolo?tab=repositories

#### spatula

#9
##### Mar 13, 2013, 05:22 pm
Hi, I'm trying to figure out what you want to do and I'm still unsure. The case I have in mind is a sort of simple calculator using postfix notation, so if you type "123+-" this is translated into ((2+3)-1). Your case is probably simpler because you seem to allow only a value followed by an operator, so you never get two consecutive values or two consecutive operators.

Both ways, you need to make a distinction between values and operators: if a value key is entered you have to save the value until an operator key is pressed (you may display the value, but that is not essential and depends on how you design your "user interface"); if an operator key is pressed you need to perform the calculation and display it. You also need to save the last result, as input to the next operation.

In the simple case, you need to keep the last result and the last value entered in a variable that is not changed on each loop(), as the counter and x variables in your code (but using more meaningful names may help understand what they are for). Nothing prevents you from storing the last result (or last value, but not both) in digitalPins. Looks boring to code, but also instructive.

P.S. just saw HazardsMind's comment, seems we are on the same track.

#### littlewolf

#10
##### Mar 14, 2013, 09:38 am
I believe the last two replies are good answers to my problem.
This is exactly what I want to do:
get a key
if the key is an integer
get the second key
if second key is '*' or '#'
then, either increase or decrease the counting by the
value of the key
I will try to modify the above code during this weekend when I have more time
You are welcome with more suggestions.
Thank you guys for your help.
Regards

#### littlewolf

#11
##### Mar 16, 2013, 10:15 am

Hi, I'm trying to figure out what you want to do and I'm still unsure. The case I have in mind is a sort of simple calculator using postfix notation, so if you type "123+-" this is translated into ((2+3)-1). Your case is probably simpler because you seem to allow only a value followed by an operator, so you never get two consecutive values or two consecutive operators.

Both ways, you need to make a distinction between values and operators: if a value key is entered you have to save the value until an operator key is pressed (you may display the value, but that is not essential and depends on how you design your "user interface"); if an operator key is pressed you need to perform the calculation and display it. You also need to save the last result, as input to the next operation.

In the simple case, you need to keep the last result and the last value entered in a variable that is not changed on each loop(), as the counter and x variables in your code (but using more meaningful names may help understand what they are for). Nothing prevents you from storing the last result (or last value, but not both) in digitalPins. Looks boring to code, but also instructive.

P.S. just saw HazardsMind's comment, seems we are on the same track.

I'm struggling to do all of this.
This is my code for now.
Code: [Select]
`/* Binary counting using 12 LEDs and a keypad to control the increasing or decreasing rate by the value of the key pressed*/#include <Keypad.h>int i;int x;int ledPin[12]={13,12,11,10,9,8,7,6,5,4,3,2};int counter;int firstKey;int secondKey;int mostSignificantBit;int leastSignificantBit;const byte ROWS = 4; //four rowsconst byte COLS = 3; //three columnschar keys[ROWS][COLS] = { {'1','2','3'}, {'4','5','6'}, {'7','8','9'}, {'*','0','#'}} byte rowPins[ROWS] = {31, 33, 35, 37}; //connect to the row pinouts of the keypadbyte colPins[COLS] = {39, 41, 43}; //connect to the column pinouts of the keypad Keypad customKeypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );void setup(){  Serial.begin(9600);   for(i=0; i<12; i++){  pinMode(ledPin[i], OUTPUT);      // sets the digital pins as output  }void loop(){    char key = customKeypad.getKey();    if (firstKey=='1') {  if (secondKey=='*'){   for(   }   else (secondKey=='#') {     for (   } } else if(firstKey=='2') {    if (secondKey=='*'){   for(   }   else (secondKey=='#') {     for (   } } else if(firstKey=='3') {  if (secondKey=='*'){   for(   }   else (secondKey=='#') {     for (   } } else if(firstKey=='4') {   if (secondKey=='*'){   for(   }   else (secondKey=='#') {     for (   } } else if(firstKey=='5') {   if (secondKey=='*'){   for(   }   else (secondKey=='#') {     for (   } } else if(firstKey=='6') {   if (secondKey=='*'){   for(   }   else (secondKey=='#') {     for (   } } else if(firstKey=='7') {   if (secondKey=='*'){   for(   }   else (secondKey=='#') {     for (   } } else if(firstKey=='8') {   if (secondKey=='*'){   for(   }   else (secondKey=='#') {     for (   } } else if(firstKey=='9') {   if (secondKey=='*'){   for(   }   else (secondKey=='#') {     for (   } } else (firstKey=='0') {   if (secondKey=='*'){   for(   }   else (secondKey=='#') {     for (   } }}`

I just wanted to make sure I am going in the right direction.
Can you check my code please to see what else is missing.
Some code examples would be useful.
I still don't know how to declare all the variables needed for my code.
Regards

#### UKHeliBob

#12
##### Mar 16, 2013, 02:41 pmLast Edit: Mar 16, 2013, 02:58 pm by UKHeliBob Reason: 1
Your code as posted does not compile.

Apart from anything else the loop() function starts before the setup() function ends
I strongly suggest that you put each curly bracket in its own line so that you can see the indentation properly
Code: [Select]
`void setup(){  Serial.begin(9600);   for(i=0; i<12; i++)   {  pinMode(ledPin[i], OUTPUT);      // sets the digital pins as output  }void loop(){`
I would like to have Auto Formatted the code but it won't due to errors in it so I will leave that to you.

I still don't understand what you are trying to do.  Can you please explain it again ?
Please do not send me PMs asking for help.  Post in the forum then everyone will benefit from seeing the questions and answers.

#### littlewolf

#13
##### Mar 16, 2013, 03:35 pm

I still don't understand what you are trying to do.  Can you please explain it again ?

Perhaps the title of my topic is the wrong one.
It should have been: "Increment/decrement binary counter by any number"
or perhaps "Control a binary counter with a keypad".

I will explain it again.
My project include an Arduino Mega, a 4/3 keypad and 12 LEDs.
I want to give the keypad keys (number keys) their values and for '*' and '#' an operator function (increment or decrement).
At any time I only want to press two keys, a value key (number keys) and an operator key.
The operator key will either increment or decrement the binary counting (displayed on LEDs) by the
value of the number key pressed.
Hope this is clear.
I had a look at the increment/decrement operators but coudn't find
how to increase the counting by 3 for example.
In my case I want to use all the numbers from 1 to 10.
Regards

#### UKHeliBob

#14
##### Mar 16, 2013, 03:42 pm
How to increase a variable called number by 3
Code: [Select]
`number += 3;`
http://arduino.cc/en/Reference/IncrementCompound

or easier to understand perhaps
Code: [Select]
`number =  number + 3;`
http://arduino.cc/en/Reference/Arithmetic
Please do not send me PMs asking for help.  Post in the forum then everyone will benefit from seeing the questions and answers.

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