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226 lines
6.4 KiB
Plaintext
226 lines
6.4 KiB
Plaintext
/*
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SCP1000 Barometric Pressure Sensor Display
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Serves the output of a Barometric Pressure Sensor as a web page.
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Uses the SPI library. For details on the sensor, see:
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http://www.sparkfun.com/commerce/product_info.php?products_id=8161
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http://www.vti.fi/en/support/obsolete_products/pressure_sensors/
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This sketch adapted from Nathan Seidle's SCP1000 example for PIC:
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http://www.sparkfun.com/datasheets/Sensors/SCP1000-Testing.zip
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Circuit:
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SCP1000 sensor attached to pins 6,7, and 11 - 13:
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DRDY: pin 6
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CSB: pin 7
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MOSI: pin 11
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MISO: pin 12
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SCK: pin 13
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created 31 July 2010
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by Tom Igoe
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*/
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#include <Ethernet.h>
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// the sensor communicates using SPI, so include the library:
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#include <SPI.h>
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// assign a MAC address for the ethernet controller.
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// fill in your address here:
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byte mac[] = {
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0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED};
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// assign an IP address for the controller:
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byte ip[] = {
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192,168,1,20 };
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byte gateway[] = {
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192,168,1,1};
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byte subnet[] = {
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255, 255, 255, 0 };
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// Initialize the Ethernet server library
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// with the IP address and port you want to use
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// (port 80 is default for HTTP):
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Server server(80);
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//Sensor's memory register addresses:
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const int PRESSURE = 0x1F; //3 most significant bits of pressure
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const int PRESSURE_LSB = 0x20; //16 least significant bits of pressure
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const int TEMPERATURE = 0x21; //16 bit temperature reading
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// pins used for the connection with the sensor
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// the others you need are controlled by the SPI library):
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const int dataReadyPin = 6;
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const int chipSelectPin = 7;
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float temperature = 0.0;
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long pressure = 0;
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long lastReadingTime = 0;
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void setup() {
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// start the SPI library:
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SPI.begin();
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// start the Ethernet connection and the server:
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Ethernet.begin(mac, ip);
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server.begin();
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// initalize the data ready and chip select pins:
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pinMode(dataReadyPin, INPUT);
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pinMode(chipSelectPin, OUTPUT);
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Serial.begin(9600);
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//Configure SCP1000 for low noise configuration:
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writeRegister(0x02, 0x2D);
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writeRegister(0x01, 0x03);
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writeRegister(0x03, 0x02);
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// give the sensor and Ethernet shield time to set up:
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delay(1000);
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//Set the sensor to high resolution mode tp start readings:
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writeRegister(0x03, 0x0A);
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}
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void loop() {
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// check for a reading no more than once a second.
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if (millis() - lastReadingTime > 1000){
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// if there's a reading ready, read it:
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// don't do anything until the data ready pin is high:
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if (digitalRead(dataReadyPin) == HIGH) {
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getData();
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// timestamp the last time you got a reading:
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lastReadingTime = millis();
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}
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}
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// listen for incoming Ethernet connections:
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listenForClients();
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}
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void getData() {
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Serial.println("Getting reading");
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//Read the temperature data
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int tempData = readRegister(0x21, 2);
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// convert the temperature to celsius and display it:
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temperature = (float)tempData / 20.0;
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//Read the pressure data highest 3 bits:
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byte pressureDataHigh = readRegister(0x1F, 1);
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pressureDataHigh &= 0b00000111; //you only needs bits 2 to 0
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//Read the pressure data lower 16 bits:
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unsigned int pressureDataLow = readRegister(0x20, 2);
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//combine the two parts into one 19-bit number:
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pressure = ((pressureDataHigh << 16) | pressureDataLow)/4;
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Serial.print("Temperature: ");
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Serial.print(temperature);
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Serial.println(" degrees C");
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Serial.print("Pressure: " + String(pressure));
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Serial.println(" Pa");
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}
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void listenForClients() {
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// listen for incoming clients
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Client client = server.available();
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if (client) {
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Serial.println("Got a client");
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// an http request ends with a blank line
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boolean currentLineIsBlank = true;
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while (client.connected()) {
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if (client.available()) {
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char c = client.read();
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// if you've gotten to the end of the line (received a newline
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// character) and the line is blank, the http request has ended,
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// so you can send a reply
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if (c == '\n' && currentLineIsBlank) {
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// send a standard http response header
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client.println("HTTP/1.1 200 OK");
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client.println("Content-Type: text/html");
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client.println();
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// print the current readings, in HTML format:
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client.print("Temperature: ");
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client.print(temperature);
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client.print(" degrees C");
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client.println("<br />");
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client.print("Pressure: " + String(pressure));
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client.print(" Pa");
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client.println("<br />");
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break;
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}
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if (c == '\n') {
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// you're starting a new line
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currentLineIsBlank = true;
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}
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else if (c != '\r') {
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// you've gotten a character on the current line
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currentLineIsBlank = false;
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}
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}
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}
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// give the web browser time to receive the data
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delay(1);
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// close the connection:
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client.stop();
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}
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}
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//Send a write command to SCP1000
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void writeRegister(byte registerName, byte registerValue) {
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// SCP1000 expects the register name in the upper 6 bits
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// of the byte:
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registerName <<= 2;
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// command (read or write) goes in the lower two bits:
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registerName |= 0b00000010; //Write command
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// take the chip select low to select the device:
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digitalWrite(chipSelectPin, LOW);
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SPI.transfer(registerName); //Send register location
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SPI.transfer(registerValue); //Send value to record into register
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// take the chip select high to de-select:
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digitalWrite(chipSelectPin, HIGH);
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}
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//Read register from the SCP1000:
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unsigned int readRegister(byte registerName, int numBytes) {
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byte inByte = 0; // incoming from the SPI read
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unsigned int result = 0; // result to return
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// SCP1000 expects the register name in the upper 6 bits
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// of the byte:
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registerName <<= 2;
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// command (read or write) goes in the lower two bits:
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registerName &= 0b11111100; //Read command
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// take the chip select low to select the device:
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digitalWrite(chipSelectPin, LOW);
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// send the device the register you want to read:
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int command = SPI.transfer(registerName);
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// send a value of 0 to read the first byte returned:
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inByte = SPI.transfer(0x00);
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result = inByte;
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// if there's more than one byte returned,
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// shift the first byte then get the second byte:
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if (numBytes > 1){
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result = inByte << 8;
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inByte = SPI.transfer(0x00);
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result = result |inByte;
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}
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// take the chip select high to de-select:
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digitalWrite(chipSelectPin, HIGH);
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// return the result:
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return(result);
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}
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