+/*
+ Updated code for receiving data from WH2 weather station
+ This code implements timeouts to make decoding more robust
+ Decodes received packets and writes a summary of each packet to the Arduino's
+ serial port
+ Created by Luc Small on 19 July 2013.
+ Released into the public domain.
+*/
+
+#include <dht.h>
+#include <Wire.h>
+#include <BMP085.h>
+
+// DHT11 and BMP085 wired sensors
+dht DHT;
+BMP085 bmp;
+
+// Humidity sensor at pin 4
+#define DHT11PIN 5
+
+#define DEBUG
+
+// LED pins
+#define REDPIN 11
+#define GREENPIN 12
+
+// Read data from 433MHz receiver on digital pin 3
+#define RF_IN 4
+// For better efficiency, the port is read directly
+// the following two lines should be changed appropriately
+// if the line above is changed.
+#define RF_IN_RAW PIND4
+#define RF_IN_PIN PIND
+
+// Port that is hooked to LED to indicate a packet has been received
+
+#define COUNTER_RATE 3200-1 // 16,000,000Hz / 3200 = 5000 interrupts per second, ie. 200us between interrupts
+// 1 is indicated by 500uS pulse
+// wh2_accept from 2 = 400us to 3 = 600us
+#define IS_HI_PULSE(interval) (interval >= 2 && interval <= 3)
+// 0 is indicated by ~1500us pulse
+// wh2_accept from 7 = 1400us to 8 = 1600us
+#define IS_LOW_PULSE(interval) (interval >= 7 && interval <= 8)
+// worst case packet length
+// 6 bytes x 8 bits x (1.5 + 1) = 120ms; 120ms = 200us x 600
+#define HAS_TIMED_OUT(interval) (interval > 600)
+// we expect 1ms of idle time between pulses
+// so if our pulse hasn't arrived by 1.2ms, reset the wh2_packet_state machine
+// 6 x 200us = 1.2ms
+#define IDLE_HAS_TIMED_OUT(interval) (interval > 6)
+// our expected pulse should arrive after 1ms
+// we'll wh2_accept it if it arrives after
+// 4 x 200us = 800us
+#define IDLE_PERIOD_DONE(interval) (interval >= 4)
+// Shorthand for tests
+//#define RF_HI (digitalRead(RF_IN) == HIGH)
+//#define RF_LOW (digitalRead(RF_IN) == LOW)
+#define RF_HI (bit_is_set(RF_IN_PIN, RF_IN_RAW))
+#define RF_LOW (bit_is_clear(RF_IN_PIN, RF_IN_RAW))
+
+// wh2_flags
+#define GOT_PULSE 0x01
+#define LOGIC_HI 0x02
+volatile byte wh2_flags = 0;
+volatile byte wh2_packet_state = 0;
+volatile int wh2_timeout = 0;
+byte wh2_packet[5];
+byte wh2_calculated_crc;
+
+
+#ifdef DEBUG
+byte printed = 0;
+#endif
+
+ISR(TIMER1_COMPA_vect)
+{
+ static byte sampling_state = 0;
+ static byte count;
+ static boolean was_low = false;
+
+ switch(sampling_state) {
+ case 0: // waiting
+ wh2_packet_state = 0;
+ if (RF_HI) {
+ if (was_low) {
+ count = 0;
+ sampling_state = 1;
+ was_low = false;
+ }
+ } else {
+ was_low = true;
+ }
+ break;
+ case 1: // acquiring first pulse
+ count++;
+ // end of first pulse
+ if (RF_LOW) {
+ if (IS_HI_PULSE(count)) {
+ wh2_flags = GOT_PULSE | LOGIC_HI;
+ sampling_state = 2;
+ count = 0;
+ } else if (IS_LOW_PULSE(count)) {
+ wh2_flags = GOT_PULSE; // logic low
+ sampling_state = 2;
+ count = 0;
+ } else {
+ sampling_state = 0;
+ }
+ }
+ break;
+ case 2: // observe 1ms of idle time
+ count++;
+ if (RF_HI) {
+ if (IDLE_HAS_TIMED_OUT(count)) {
+ sampling_state = 0;
+ } else if (IDLE_PERIOD_DONE(count)) {
+ sampling_state = 1;
+ count = 0;
+ }
+ }
+ break;
+ }
+
+ if (wh2_timeout > 0) {
+ wh2_timeout++;
+ if (HAS_TIMED_OUT(wh2_timeout)) {
+ wh2_packet_state = 0;
+ wh2_timeout = 0;
+#ifdef DEBUG
+ if (printed) {
+ Serial1.println();
+ printed=0;
+ }
+#endif
+ }
+ }
+}
+
+void setup() {
+
+ Serial1.begin(57600);
+ Serial1.println();
+ Serial1.println("STATUS:STARTING");
+
+ bmp.begin();
+
+ pinMode(REDPIN,OUTPUT);
+ pinMode(GREENPIN,OUTPUT);
+
+ pinMode(RF_IN, INPUT);
+ digitalWrite(RF_IN,HIGH);
+
+ TCCR1A = 0x00;
+ TCCR1B = 0x09;
+ TCCR1C = 0x00;
+ OCR1A = COUNTER_RATE;
+ TIMSK1 = 0x02;
+
+ // enable interrupts
+ sei();
+}
+
+unsigned long previousMillis = 0;
+unsigned long indoor_interval = 60000;
+unsigned long outdoor_interval = 45000;
+unsigned long previousIndoor = 0;
+unsigned long previousOutdoor = 0;
+
+
+void loop() {
+ unsigned long now;
+ byte i;
+
+ now = millis();
+
+ if (wh2_flags) {
+ if (wh2_accept()) {
+ // calculate the CRC
+ wh2_calculate_crc();
+
+ if (wh2_valid()) {
+
+ Serial1.println();
+ Serial1.print("SENSOR:TYPE=OUTDOOR,");
+
+ Serial1.print("ID=");
+ Serial1.print(wh2_sensor_id(), HEX);
+
+ Serial1.print(",HUMIDITY=");
+ Serial1.print(wh2_humidity(), DEC);
+
+ Serial1.print(",TEMPERATURE=");
+ Serial1.println(format_temp(wh2_temperature()));
+
+ previousOutdoor = now;
+ digitalWrite(REDPIN,HIGH);
+
+ } else {
+
+ Serial1.println();
+ Serial1.println("ERROR:OUTDOOR");
+ previousOutdoor = now;
+ digitalWrite(REDPIN,LOW);
+
+ }
+
+ }
+ wh2_flags = 0x00;
+ }
+
+ if ((unsigned long)(now - previousMillis) >= indoor_interval) {
+
+ previousMillis = now;
+
+ int chk = DHT.read11(DHT11PIN);
+
+ if (chk==0) {
+
+ Serial1.println();
+ Serial1.print("SENSOR:TYPE=INDOOR,");
+ Serial1.print("HUMIDITY=");
+ Serial1.print(DHT.humidity);
+ Serial1.print(",TEMPERATURE=");
+ Serial1.print(DHT.temperature);
+
+ Serial1.println();
+ Serial1.print("SENSOR:TYPE=BARO,");
+ Serial1.print("PRESSURE=");
+ Serial1.print(bmp.readPressure());
+ Serial1.print(",TEMPERATURE=");
+ Serial1.println(bmp.readTemperature());
+
+ previousIndoor = now;
+ digitalWrite(GREENPIN,HIGH);
+
+
+ } else {
+
+ Serial1.println();
+ Serial1.println("ERROR:INDOOR");
+ previousIndoor = now;
+ digitalWrite(GREENPIN,LOW);
+
+ }
+
+ }
+
+ if ((unsigned long)(now - previousIndoor) > indoor_interval*10) {
+
+ Serial1.println();
+ Serial1.println("ERROR:INDOOR TIMEOUT");
+ previousIndoor = now;
+ digitalWrite(GREENPIN,LOW);
+
+ }
+
+ if ((unsigned long)(now - previousOutdoor) > outdoor_interval*10) {
+
+ Serial1.println();
+ Serial1.println("ERROR:OUTDOOR TIMEOUT");
+ previousOutdoor = now;
+ digitalWrite(REDPIN,LOW);
+
+ }
+
+
+}
+
+
+// processes new pulse
+boolean wh2_accept()
+{
+ static byte packet_no, bit_no, history;
+
+ // reset if in initial wh2_packet_state
+ if(wh2_packet_state == 0) {
+ // should history be 0, does it matter?
+ history = 0xFF;
+ wh2_packet_state = 1;
+ // enable wh2_timeout
+ wh2_timeout = 1;
+ } // fall thru to wh2_packet_state one
+
+ // acquire preamble
+ if (wh2_packet_state == 1) {
+ // shift history right and store new value
+ history <<= 1;
+ // store a 1 if required (right shift along will store a 0)
+ if (wh2_flags & LOGIC_HI) {
+ history |= 0x01;
+ }
+ // check if we have a valid start of frame
+ // xxxxx110
+ if ((history & B00000111) == B00000110) {
+ // need to clear packet, and counters
+ packet_no = 0;
+ // start at 1 becuase only need to acquire 7 bits for first packet byte.
+ bit_no = 1;
+ wh2_packet[0] = wh2_packet[1] = wh2_packet[2] = wh2_packet[3] = wh2_packet[4] = 0;
+ // we've acquired the preamble
+ wh2_packet_state = 2;
+ }
+ return false;
+ }
+ // acquire packet
+ if (wh2_packet_state == 2) {
+
+ wh2_packet[packet_no] <<= 1;
+ if (wh2_flags & LOGIC_HI) {
+ wh2_packet[packet_no] |= 0x01;
+#ifdef DEBUG
+ Serial1.print('1');
+ printed=1;
+ } else {
+ Serial1.print('0');
+ printed=1;
+#endif
+ }
+
+ bit_no ++;
+ if(bit_no > 7) {
+ bit_no = 0;
+ packet_no ++;
+ }
+
+ if (packet_no > 4) {
+ // start the sampling process from scratch
+ wh2_packet_state = 0;
+ // clear wh2_timeout
+ wh2_timeout = 0;
+ return true;
+ }
+ }
+ return false;
+}
+
+
+void wh2_calculate_crc()
+{
+ wh2_calculated_crc = crc8(wh2_packet, 4);
+}
+
+bool wh2_valid()
+{
+ return (wh2_calculated_crc == wh2_packet[4]);
+}
+
+int wh2_sensor_id()
+{
+ return (wh2_packet[0] << 4) + (wh2_packet[1] >> 4);
+}
+
+byte wh2_humidity()
+{
+ return wh2_packet[3];
+}
+
+/* Temperature in deci-degrees. e.g. 251 = 25.1 */
+int wh2_temperature()
+{
+ int temperature;
+ temperature = ((wh2_packet[1] & B00000111) << 8) + wh2_packet[2];
+ // make negative
+ if (wh2_packet[1] & B00001000) {
+ temperature = -temperature;
+ }
+ return temperature;
+}
+
+String format_temp(int temperature)
+{
+ byte whole, partial;
+ String s;
+ s = String();
+ if (temperature<0) {
+ temperature = -temperature;
+ s += String('-');
+ }
+
+ whole = temperature / 10;
+ partial = temperature - (whole*10);
+
+ s += String(whole, DEC);
+ s += '.';
+ s += String(partial, DEC);
+
+ return s;
+
+}
+
+uint8_t crc8( uint8_t *addr, uint8_t len)
+{
+ uint8_t crc = 0;
+
+ // Indicated changes are from reference CRC-8 function in OneWire library
+ while (len--) {
+ uint8_t inbyte = *addr++;
+ for (uint8_t i = 8; i; i--) {
+ uint8_t mix = (crc ^ inbyte) & 0x80; // changed from & 0x01
+ crc <<= 1; // changed from right shift
+ if (mix) crc ^= 0x31;// changed from 0x8C;
+ inbyte <<= 1; // changed from right shift
+ }
+ }
+ return crc;
+}
+
+
+
+
+
+
+
+
+
projects / weathermon.git / commitdiff