Jason Schilling / Mbed 2 deprecated logTemp

logging temp with sd card

Dependencies:   mbed SDFileSystem

main.cpp@0:9dfb24edf079, 2019-03-19 (annotated)

Committer:
jschilling22
Date:
Tue Mar 19 16:45:48 2019 +0000
Revision:
0:9dfb24edf079
logging

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jschilling22 0:9dfb24edf079 1 /* Program demonstrating data logging to SD card
jschilling22 0:9dfb24edf079 2 Temperature is read in from an TMP36
jschilling22 0:9dfb24edf079 3 The time since program start and the voltage
jschilling22 0:9dfb24edf079 4 are written to a tab-delimited data file.
jschilling22 0:9dfb24edf079 5 TMP36 pins: left = power, middle = output (p18), right = ground
jschilling22 0:9dfb24edf079 6 SD pins: DI = p5, DO = p6, SCK = p7, CS = p8
jschilling22 0:9dfb24edf079 7 */
jschilling22 0:9dfb24edf079 8 #include "mbed.h"
jschilling22 0:9dfb24edf079 9 #include "SDFileSystem.h"
jschilling22 0:9dfb24edf079 10
jschilling22 0:9dfb24edf079 11 AnalogIn tmp36(p18);
jschilling22 0:9dfb24edf079 12 Serial pc(USBTX,USBRX);
jschilling22 0:9dfb24edf079 13 SDFileSystem fs(p5, p6, p7, p8, "fs");
jschilling22 0:9dfb24edf079 14 Timer t;
jschilling22 0:9dfb24edf079 15 Ticker sampleTime;
jschilling22 0:9dfb24edf079 16 DigitalOut doneLED(LED1);
jschilling22 0:9dfb24edf079 17 bool timeToRead;
jschilling22 0:9dfb24edf079 18
jschilling22 0:9dfb24edf079 19 void triggerCollection() {
jschilling22 0:9dfb24edf079 20 timeToRead = true; // flag to collect data
jschilling22 0:9dfb24edf079 21 }
jschilling22 0:9dfb24edf079 22
jschilling22 0:9dfb24edf079 23 int main() {
jschilling22 0:9dfb24edf079 24
jschilling22 0:9dfb24edf079 25 float voltage, temperature;
jschilling22 0:9dfb24edf079 26 // Mount the filesystem
jschilling22 0:9dfb24edf079 27 bool mountFailure = fs.mount();
jschilling22 0:9dfb24edf079 28 if (mountFailure != 0) {
jschilling22 0:9dfb24edf079 29 pc.printf("Failed to mount the SD card.\r\n");
jschilling22 0:9dfb24edf079 30 return -1; // ends program with error status
jschilling22 0:9dfb24edf079 31 }
jschilling22 0:9dfb24edf079 32
jschilling22 0:9dfb24edf079 33 FILE* fp = fopen("/fs/log.txt","w");
jschilling22 0:9dfb24edf079 34 if (fp == NULL) {
jschilling22 0:9dfb24edf079 35 pc.printf("Failed to open the file.\r\n");
jschilling22 0:9dfb24edf079 36 fs.unmount();
jschilling22 0:9dfb24edf079 37 return -1;
jschilling22 0:9dfb24edf079 38 }
jschilling22 0:9dfb24edf079 39
jschilling22 0:9dfb24edf079 40 // Write a header row
jschilling22 0:9dfb24edf079 41 fprintf(fp, "Time (s) \t Temperature (deg C)\r\n");
jschilling22 0:9dfb24edf079 42
jschilling22 0:9dfb24edf079 43 // Start the timer and ticker
jschilling22 0:9dfb24edf079 44 t.start();
jschilling22 0:9dfb24edf079 45 sampleTime.attach(&triggerCollection, 0.5); // write data every 0.5 s
jschilling22 0:9dfb24edf079 46 timeToRead = true; // collect data at t = 0
jschilling22 0:9dfb24edf079 47
jschilling22 0:9dfb24edf079 48 while (t.read()<20) {
jschilling22 0:9dfb24edf079 49 if (timeToRead) {
jschilling22 0:9dfb24edf079 50 timeToRead = false; // reset data collection flag
jschilling22 0:9dfb24edf079 51 voltage = 3.3*tmp36.read();
jschilling22 0:9dfb24edf079 52 temperature = (voltage-0.5)/0.01;
jschilling22 0:9dfb24edf079 53 fprintf(fp,"%.2f \t %.2f\r\n", t.read(),temperature);
jschilling22 0:9dfb24edf079 54 }
jschilling22 0:9dfb24edf079 55 }
jschilling22 0:9dfb24edf079 56
jschilling22 0:9dfb24edf079 57 // Close the file and unmount the file system so the SD card is happy
jschilling22 0:9dfb24edf079 58 fclose(fp);
jschilling22 0:9dfb24edf079 59 fs.unmount();
jschilling22 0:9dfb24edf079 60 // Turn on LED to let user know it is safe to remove the SD card
jschilling22 0:9dfb24edf079 61 doneLED = 1;
jschilling22 0:9dfb24edf079 62 }