I have constructed an indoor weather station using an Arduino 2009.
It has a temperature sensor:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1259616399It has a humidity sensor:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1264143673It has a air pressure sensor:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1264823064/0#0I can store up to 3 years of data on a 1Gb sd card.
I have used a sd card library class:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1259789744/0#0The arduino code :
/* On restart sends serial "ready" and current sd sector number.
Current sd sector number held in EEPROM.
Repeat every 10 seconds
PC sends sd sector number to use and we start to get samples.
Every 10 secs sample temperature humidity and airpressure.
Send samples to PC and store in RAM.
If 85 samples(255 bytes)in RAM save in sd card.
If receive "u" and number from PC send requested sd sectors
and RAM to the PC.
If error in read/write to sd card stay in a loop and
send "error" to PC every 10 seconds.
*/
#include <EEPROM.h>
#include <SDCARD.h> //read write 512 blocks to sd card
#include <stdlib.h> // C utility functions
volatile unsigned char buffer[512] ; //RAM store for samples
unsigned long lastmillis = 0; // will store last time we looked
unsigned int tempsample = 0; //adc temp averaged each 10 seconds
const int tempadc = 1; // Analog input pin for temperature
const int pin = 7; // digital input pin for humidity
const int sensor_offset = 1889; //the offset to give correct RH value
unsigned long duration; //pulse time of HCH-1000 timer
unsigned int humidsample = 0; //humid averaged each 10 seconds
unsigned int airsample =0; //adc air averaged each 10 seconds
const int airadc = 0; // Analog input pin for air pressure
unsigned int ramaddress =0; //address of next storage location in RAM
unsigned long currentblock = 0; //the current block number in the sd card
unsigned long loadblocks = 0; //the start upload sector from computer
int inbyte = 0; // character input from computer in ASCII
char restartblock[8]; //the computer inputs the startblock number
boolean restarted = false; //set when the computer restarts the avr
void setup()
{
Serial.begin(9600); // initialize serial communication with computer
pinMode(9, OUTPUT); // sets the digital pin as output for sample flash
pinMode(8, OUTPUT); // sets the digital pin as output for sd card error
pinMode(pin, INPUT); //humidity input
digitalWrite(8, LOW); //start with sd card error led off
}
void loop()
{
if ( ! restarted) // if not restarted
{
while (Serial.available() == 0) //wait until computer is connected
{
ready(); //after restart send ready message
}//end of wait till computer connected
getcurrentblock(); //get the current block from computer
}//end of not restarted
if (millis() < lastmillis)
lastmillis = 0; //have a rollover every 52 days
if (millis() - lastmillis > 10000) //every 10 seconds
{
lastmillis += 10000; // update the timer
digitalWrite(9, HIGH); //flash the led to show sampling
if (Serial.available() > 0) //do we have a computer command
{
inbyte = Serial.read(); //get the command
if (inbyte == 'u') //download all the stored samples
{ // computer sends "r4444" to upload all RAM and sd blocks from 4444
byte j = 0; // for start counter enter digits
for (j = 0; j < 8 ; j +=1)
restartblock[j] = '0'; //clear the buffer before read
while (Serial.available() != 0) //input the sd card start block
{
restartblock[j] = Serial.read();
j +=1; //next digit position
}//end of input sd card start block
loadblocks = strtoul(restartblock,0,10); //this is requested atarting block
if (loadblocks > currentblock)
loadblocks = currentblock; //we must never have or runs through whole card
uploadbuffer(ramaddress); //upload the current sample that are in ram
Serial.println("r"); //tell computer all RAM samples are sent
uploadsdblocks(); //upload the requested sd blocks
Serial.println("e"); //tell computer all samples are sent
}//end of download all stored sample samples
}//end of we have a computer command
tempsample = adc(tempadc); //get the analog sample for temperature
airsample = adc(airadc); //get analog sample for air pressure
humidity(); //get the sample for the humidity
sendsample(); //send a sample to the computer
if (ramaddress == 510) //have we have filled the ram buffer
{
lastblocksave(); //saved full ram to sd card so save block number
}//end of have we filled the ram buffer
}//end of every 10 seconds
digitalWrite(9, LOW); //turn led off
}//end of loop
inline unsigned int adc(int pin)
{
unsigned int sample = 0; //reset the sample value
//tempsample = 0; //reset the average
int i = 0;
for(i; i<=64; i++)
sample += analogRead(pin); //get 64 samples added together 1024 x 64 max
sample = sample / 64; //get the average of 64 samples
return sample;
//tempsample +=sample; //add the 10 second sample
}//end of adc
The arduino 2009 acts as a standalone weather station.
It does not display the data.It can operate independantly for months.
It samples the sensors until the RAM is full then The ram samples
are stored on a sector of a sd card.
Eventually a 3 years weather samples could be on on the 1Gb sd card.
Each time the PC is connected any unstored sectors are uploaded to
files on the PC's hard drive.
It then can be displayed using all the facilities of the PC's display.
The central idea is that the PC has a file copy of each sd card sector
stamped with the datetime it was recorded.
I have used visual basic for the PC program.
I find it easy to use when constructing GUI applications.
It does lock you in to windows but I can live with that.
Microsoft has a free download:
http://www.microsoft.com/express/Downloads/Download-2008.aspx#2008-Visual-BasicIf you have visual basic on your PC you can try my program.
You dont need an arduino it has 4 days of example data.
The programs and other files are at the site given below.
Download indoorweather.zip
http://sourceforge.net/projects/arduinoweather/files/
