Pressure Plug Code « Jee Labs Talk

Pressure Plug Code

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hve

I have a pressure plug working on a JeeNode, transmitting atmospheric pressure to the receiving JN connected to the computer. I am using this code:

void loop() {
  //Serial.print("\n A;
       // switch to idle mode while waiting for the next event
       lowPower(SLEEPMODEIDLE);
       // keep the easy tranmission mechanism going
       if (radioIsOn && rf12easyPoll() == 0) {
        rf12sleep(0); // turn the radio off
        radioIsOn = 0;
    }
        // if we will wait for quite some time, go into total power down mode
        if (!radioIsOn){
         //Serial.print("\n B;
        loseSomeTime(readoutTimer.remaining());
   }
//Serial.print("\n AA;
      if (readoutTimer.poll(1000)) {
//Serial.print("\n C;
          long tempF;
          float presHg;
          uint16t traw = psensor.measure(BMP085::TEMP);
          uint16t praw = psensor.measure(BMP085::PRES);
            // omit following code to avoid linking in some complex calculation code
           int16t temp;
           int32t pres;
           psensor.calculate(temp, pres);
          // Serial.print (pres);                        //for testing
           tempF=(((temp.9)/5.0)+32.0);    //convert Celcius to Fahrenheit
           //long value= pres;
           //rf12easySend(&value, sizeof value); 
            presHg=(pres0.00029529983071);  //convert pascals to in of Hg
           //Serial.println (presHg);                     //for testing
           presHg=(presHg+.625)10000;          //elevation correction +resolution adjusdment
 //Serial.print("\n D;
           long value= presHg;
           char sending = rf12easySend(&value, sizeof value);
           // force a "sign of life" packet out every 60 seconds
               if (aliveTimer.poll(60000)){
 //Serial.print("\n E;
               sending = rf12easySend(0, 0); // always returns 1
               }
                  if (sending) {
                   // make sure the radio is on again
 //Serial.print("\n F;
                   if (!radioIsOn)
                   rf12sleep(-1); // turn the radio back on
                   radioIsOn = 1;
                    }
 //Serial.print("\n G;
          }
 //Serial.print("\n H;
       }  
/pre>  
The Serial prints are for debugging.  The pressure changes in the fourth and fifth decimal place and therefore the data is transmitted almost constantly.  How can I average the data over some period to minimize the transmissions.  I need two decimal place accuracy.
This is would the receiving software gets.
>May 3, 2010 3:50:39 PM 29.8407 Hg
   > May 3, 2010 3:50:40 PM 
  > OK 33 176 141 4 0
   > node id: 1
    >May 3, 2010 3:50:40 PM 29.8416 Hg
 >  May 3, 2010 3:50:41 PM 
  > OK 33 167 141 4 0
    >node id: 1
   >May 3, 2010 3:50:41 PM 29.8407 Hg
   >May 3, 2010 3:50:42 PM 
   >OK 33 159 141 4 0
    >node id: 1
>May 3, 2010 3:50:42 PM 29.8399 Hg
You can see that If it only changes for the last two digits
Any suggestions?  Thanks for your help.


				Posted 03/05/2010 19:36:43


	
		
			
								
					jcw

				
			
			
				
Please indent your code with four spaces and a blank line before and after. Your main question is running off the page - I think it is about to fall off ;)



				Posted 03/05/2010 20:39:31
			
		
	
	
		
			
								
					epokh

				
			
			
				
lol



				Posted 03/05/2010 21:52:41
			
		
	
	
		
			
								
					hve

				
			
			
				
Sorry about that.  It took me about an hour to get it this far.  You should have seen it when I first posted it. The question I  asking help for it:
The Serial prints are for debugging.  The pressure changes in the fourth and fifth decimal place and therefore the data is transmitted almost constantly.  How can I average the data over some period to minimize the transmissions.  I need two decimal place accuracy not four.
The new question is, can I right shift the number to eliminate the right most two digits?



				Posted 03/05/2010 23:35:25
			
		
	
	
		
			
								
					jcw

				
			
			
				
When it doesn't work, I tend to reduce, reduce, reduce. My comment about indenting was made in a joking manner, but it really is important to quote your examples right - there are several cases where \'s get eaten by the Markdown formatter. By indenting every line with four spaces, you avoid that - the <pre>'s create problems of their own.
I suggest re-trying from here:
    void loop() {
        if (readoutTimer.poll(1000)) {
            psensor.measure(BMP085::TEMP);
            psensor.measure(BMP085::PRES);
            int16t temp;
            int32t pres;
            psensor.calculate(temp, pres);
            long tempF = temp  .9 / 5 + 32; // not used here
            long value = (pres  0.00029529983071 + .625)  10000;
            rf12easySend(&value, sizeof value);
        }  
    }
You're getting 4 decimals due to the " 10000" scaling - change that to 100 to get 2 decimals, etc.



				Posted 04/05/2010 00:43:11
			
		
	
	
		
			
								
					jcw

				
			
			
				
Make sure you're getting essentially the right info first.
(big pause)
Then, if you want to further reduce the remaining jitter, look into "digital smoothing" and "running averages" - Paul Badger wrote some code for that, see 



				Posted 04/05/2010 00:56:34
			
		
	
	
		
			
								
					hve

				
			
			
				
Thanks Jean-Claude.  I am getting the right information now.  I just need to figure out to average or smooth it before decision is made to send or not to send.



				Posted 04/05/2010 03:03:57