Noob question

Forum 2005-2010 (read only) Software Syntax & Programs
1

Hi peeps, my coding skills are rather limited & I need a few pointers. I'm reading 4 digital inputs and, depending on their value, setting 8 digital outputs. As I need to drive 8 outputs from just 4 inputs I'm using some simple binary to handle it. For example:

If input: pin 1=LOW, pin 2=LOW, pin 3=LOW, pin 4=HIGH then that's a binary 1 so set digital output pin 1 to HIGH

And so forth...

Here's my code so far, I'm struggling!

int outPins[] = {2,3,4,5,6,7,8,9}; // array of the output pins connected to the driver board
int inPins[] = {10,11,12,13}; // array of the input pins
int val = 0; // variable for reading the pin status
int inputstatus[] = {10,11,12,13}; // array of the input pin status
int num_outpins = 6; // the number of output pins (i.e. the length of the array)
int num_inpins = 4; // the number of input pins (i.e. the length of the array)

void setup()
{
int i;
for (i = 0; i < num_outpins; i++) // the array elements are numbered from 0 to num_outpins - 1
pinMode(outPins*, OUTPUT); // set each pin as an output*
}
{

  • int g;*
  • for (g = 0; g < num_inpins; g++) // the array elements are numbered from 0 to num_inpins - 1*
    _ pinMode(inPins*, INPUT); // set each pin as an input*_
    }
    void loop(){
    * //check input pins*
    * int f;*
    * for (f = 0; g < num_inpins; f++) // the array elements are numbered from 0 to num_inpins - 1*
    * inputstatus[f] = digitalRead([f]); // read input values*
    * // now set the pins that only have a single value*

* if (inPins(4) == HIGH) { // check if the input is HIGH - that means the corrsponding relay should be turned on*
* digitalWrite(outPins(2), HIGH); // turn output pin 2 On*
* }*
* if (inPins(3) == HIGH) { // check if the input is HIGH - that means the corrsponding relay should be turned on*
* digitalWrite(outPins(3), HIGH); // turn output pin 3 On*

* }*
* if (inPins(2) == HIGH) { // check if the input is HIGH - that means the corrsponding relay should be turned on*
* digitalWrite(outPins(3), HIGH); // turn output pin 3 On*
* }*

* if (inPins(1) == HIGH) { // check if the input is HIGH - that means the corrsponding relay should be turned on*
* digitalWrite(outPins(8), HIGH); // turn output pin 8 On*
* }*

}

}

2

How about making a number from the binary inputs using something like:-

num = digitalRead(inPins[0]) | (digitalRead(inPins[1]) << 1) | (digitalRead(inPins[2]) << 2) | (digitalRead(inPins[3]) << 3);

the | symbol is a bit wise OR function you could replace it with a + here but that's a bit wimpy.

Then use a case statement on num to set the output to what you want.

(you can simplify the case statement to some algorithem but get your head round this first)

3

i'd keep an eye on your brackets, [] are used in arrays and () are used for function inputs. your code seems to mix and match them

4

I like Grumpy_Mike's suggestion.

It's also worth nothing that 4 inputs can generate 16 different possible outcomes, not 8.

Mikal