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Fridgelogger power source

by bmco2n on Tue Feb 05, 2013 11:17 pm

Dear Forum,

My fridgelogger prints time, light and temp data OK to the SD card when it's connected to the USB computer, but won't print to the card if external power is used. Can you look at my sketch and find the mistake? If it's able to Serial.print, it works, but if not (external power), it won't. :?

Code: Select all | TOGGLE FULL SIZE
//this works, FILES ARE INCREMENTED AND PRINTED TO OK ON SD.
// BUT won't print to SD card from external power.

#include <SD.h>
#include <Wire.h>
#include "RTClib.h"

// A simple data logger for the Arduino analog pins

// how many milliseconds between grabbing data and logging it. 1000 ms is once a second
#define LOG_INTERVAL  3000 // mills between entries (reduce to take more/faster data)

// how many milliseconds before writing the logged data permanently to disk
// set it to the LOG_INTERVAL to write each time (safest)
// set it to 10*LOG_INTERVAL to write all data every 10 datareads, you could lose up to
// the last 10 reads if power is lost but it uses less power and is much faster!
#define SYNC_INTERVAL 3000 // mills between calls to flush() - to write data to the card
uint32_t syncTime = 0; // time of last sync()

#define ECHO_TO_SERIAL   1 // echo data to serial port
#define WAIT_TO_START    0 // Wait for serial input in setup()

// the digital pins that connect to the LEDs
#define redLEDpin 2
#define greenLEDpin 3

// The analog pins that connect to the sensors
#define photocellPin 0           // analog 0
#define tempPin 1                // analog 1
#define BANDGAPREF 14            // special indicator that we want to measure the bandgap

#define aref_voltage 3.3         // we tie 3.3V to ARef and measure it with a multimeter!
#define bandgap_voltage 1.1      // this is not super guaranteed but its not -too- off

RTC_DS1307 RTC; // define the Real Time Clock object

// for the data logging shield, we use digital pin 10 for the SD cs line
const int chipSelect = 4;

// the logging file
File logfile;

void error(char *str)
{
  Serial.print("error: ");
  Serial.println(str);
 
  // red LED indicates error
  digitalWrite(redLEDpin, HIGH);

  while(1);
}

void setup(void)
{
  Serial.begin(9600);
  Serial.println();
 
  // use debugging LEDs
  pinMode(redLEDpin, OUTPUT);
  pinMode(greenLEDpin, OUTPUT);
 
#if WAIT_TO_START
  Serial.println("Type any character to start");
  while (!Serial.available());
#endif //WAIT_TO_START

  // initialize the SD card
  Serial.print("Initializing SD card...");
  // make sure that the default chip select pin is set to
  // output, even if you don't use it:
  pinMode(4, OUTPUT);
 
  // see if the card is present and can be initialized:
  if (!SD.begin(chipSelect)) {
    error("Card failed, or not present");
  }
  Serial.println("card initialized.");
 
  // create a new file
  char filename[] = "LOGGER00.CSV";
  for (uint8_t i = 0; i < 100; i++) {
    filename[6] = i/10 + '0';
    filename[7] = i%10 + '0';
    if (! SD.exists(filename)) {
      // only open a new file if it doesn't exist
      logfile = SD.open(filename, FILE_WRITE);
      break;  // leave the loop!
    }
  }
 
  if (! logfile) {
    error("couldnt create file");
  }
 
  Serial.print("Logging to: ");
  Serial.println(filename);

  // connect to RTC
  Wire.begin(); 
  if (!RTC.begin()) {
    logfile.println("RTC failed");
#if ECHO_TO_SERIAL
    Serial.println("RTC failed");
#endif  //ECHO_TO_SERIAL
  }
 

  logfile.println("datetime,light,temp,vcc");   
#if ECHO_TO_SERIAL
  Serial.println("datetime,light,temp,vcc");
#endif //ECHO_TO_SERIAL
 
  // If you want to set the aref to something other than 5v
  analogReference(EXTERNAL);
}

void loop(void)
{
  DateTime now;

  // delay for the amount of time we want between readings
  delay((LOG_INTERVAL -1) - (millis() % LOG_INTERVAL));
 
  digitalWrite(greenLEDpin, HIGH);
 
  // log milliseconds since starting
  uint32_t m = millis();
 
#if ECHO_TO_SERIAL
  Serial.print(m);         // milliseconds since start
  Serial.print(", "); 
#endif

  // fetch the time
  now = RTC.now();
  // log time

  logfile.print(now.day(), DEC);
  logfile.print(" ");
  logfile.print(now.hour(), DEC);
  logfile.print(":");
  logfile.print(now.minute(), DEC);
  logfile.print(":");
  logfile.print(now.second(), DEC);
  logfile.print('"');
#if ECHO_TO_SERIAL
 
  Serial.print(" ");
  Serial.print(now.hour(), DEC);
  Serial.print(":");
  Serial.print(now.minute(), DEC);
  Serial.print(":");
  Serial.print(now.second(), DEC);
  Serial.print('"');
#endif //ECHO_TO_SERIAL

  analogRead(photocellPin);
  delay(10);
  int photocellReading = analogRead(photocellPin); 
 
  analogRead(tempPin);
  delay(10);
  int tempReading = analogRead(tempPin);   
 
  // converting that reading to voltage, for 3.3v arduino use 3.3, for 5.0, use 5.0
  float voltage = tempReading * aref_voltage / 1024; 
  float temperatureC = (voltage - 0.5) * 100 ;
  float temperatureF = (temperatureC * 9 / 5) + 32;
 
  logfile.print(", ");   
  logfile.print(photocellReading);
  logfile.print(", ");   
  logfile.print(temperatureF);
#if ECHO_TO_SERIAL
  Serial.print(", ");   
  Serial.print(photocellReading);
  Serial.print(", ");   
  Serial.print(temperatureF);
#endif //ECHO_TO_SERIAL

  // Log the estimated 'VCC' voltage by measuring the internal 1.1v ref
  analogRead(BANDGAPREF);
  delay(10);
  int refReading = analogRead(BANDGAPREF);
  float supplyvoltage = (bandgap_voltage * 1024) / refReading;
 
  logfile.print(", ");
  logfile.print(supplyvoltage);
#if ECHO_TO_SERIAL
  Serial.print(", ");   
  Serial.print(supplyvoltage);
#endif // ECHO_TO_SERIAL

  logfile.println();
#if ECHO_TO_SERIAL
  Serial.println();
#endif // ECHO_TO_SERIAL

  digitalWrite(greenLEDpin, LOW);

  // Now we write data to disk! Don't sync too often - requires 2048 bytes of I/O to SD card
  // which uses a bunch of power and takes time
  if ((millis() - syncTime) < SYNC_INTERVAL) return;
  syncTime = millis();
 
  // blink LED to show we are syncing data to the card & updating FAT!
  digitalWrite(redLEDpin, HIGH);
  logfile.flush();
  digitalWrite(redLEDpin, LOW);
 
}

bmco2n
 
Posts: 76
Joined: Thu Apr 14, 2011 3:34 pm

Re: Fridgelogger power source

by adafruit_support_bill on Wed Feb 06, 2013 6:02 am

What are you using for an external power source? A weak battery may not be able to supply enough current to write to the SD card.
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Re: Fridgelogger power source

by bmco2n on Thu Feb 07, 2013 8:23 pm

Greetings,

Thanks for the reply. My fault: I was aware of low battery problems, but low bats give the wrong data, yet are able to create the LOGGERNN file. Should have told you that it won't work with a regulated adapter from the house power.

Regards,

bmco2n :)
bmco2n
 
Posts: 76
Joined: Thu Apr 14, 2011 3:34 pm

Re: Fridgelogger power source

by Zener on Fri Feb 08, 2013 1:37 am

What are the specifics of the adapter? Where is it plugged in? How do you know your logger is getting power?
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Re: Fridgelogger power source

by bmco2n on Sat Feb 09, 2013 6:57 pm

It's one of the adapters I bought from Adafruit.
Model SCP0900066P AC/DC 100-240V > 9V .66A

I could tell power by the green LED on the Arduino UNO.

I've worked the program over and over and,
If the problem isn't in the program, then it's most likely with the shield, one of three Adafruit shields I purchased and tried to assemble with care and much time. I thought two of them worked, but the card fails. The third one of present interest works OK with the USB connection, but not with batteries or the above adapter. It only works, because the SD card cover is grounded. It's a long story, so we might as well forget about it. I'm getting the Arduino wireless SD shield to work.
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Joined: Thu Apr 14, 2011 3:34 pm

Re: Fridgelogger power source

by Zener on Sun Feb 10, 2013 4:16 pm

OK. As long as you didn't screw a socket adapter into the refrigerator light socket and plug the power supply in there and every time you close the door the light goes out and.....
Zener
 
Posts: 2452
Joined: Sat Feb 21, 2009 1:38 am