BCD Output?

Bear with me guys, I’ve been studyin’ this stuff for days but I’m still not sure where to go next.

Here’s where I am and what I “think” I know.

The Code

// read MPH

volatile int mphcount = 0;//see http://arduino.cc/en/Reference/Volatile
int mph = 0;
unsigned long lastmillis = 0;

void setup(){
 attachInterrupt(0, mph_anemometer, FALLING);//interrupt zero (0) is on pin two(2).

void loop(){
 if (millis() - lastmillis == 60000){  /*Uptade every minute, this will be equal to number of pulses.*/
 detachInterrupt(0);    //Disable interrupt when calculating
 mph = mphcount / 104;  /* Convert pulsecount to MPH.*/
 Serial.print("MPH =\t"); //print the word "MPH" and tab.
 Serial.print(mph); // print the mph value.
 Serial.print("\t pulsecount=\t"); //print the word "pulses".
 Serial.println(mphcount); /*print pulses per minute. And print new line or enter.*/
 mphcount = 0; // Restart the MPH counter
 lastmillis = millis(); // Uptade lasmillis
 attachInterrupt(0, mph_anemometer, FALLING);//enable interrupt

void mph_anemometer(){ /* this code will be executed every time the interrupt 0 (pin2) gets low.*/

I’m currently sending my results to the Serial Monitor as an integer?

I would like to write my results in a BCD form to pins 3-10 to get 2 digits of decimal for 7 segment Led’s using 7447 chips. 0-99 is as high as I’ll need to go. This is all about my homemade anemometer and if the wind is over 100mph I ain’t goin’ outside anyway!

What I think I need to do:

  1. 1st of all, declare the pin (array?) as outputs up top.

  2. I don’t think I need to do anything in setup. But I could be wrong. :o

  3. In the loop I need to digitalwrite something, but what? I’ve seen Disp/BIN but a straight binary output isn’t gonna give me a 2 digit decimal result. Is there a Disp/BCD?

Any pointers are appreciated.

  1. Yes.

  2. No, you need to set your output pins to OUTPUT mode.

3? Look at some libraries for 7-segment displays. Most of them will set up the "image" you want displayed for each number. Then the output function will select the correct segments to turn on and off by stepping through the digit image array.

You're going to be multiplexing the two digits? Then look at libraries available online.

Well Thank You for that. SevSeg libraries appear to be very fertile fields for further plowing. I’m on it!

And Thanx again.