227 lines
4.6 KiB
C++
227 lines
4.6 KiB
C++
/*
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RadioHead attiny85 DHT22 Weather Station
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2021 Stefan Ostermann based on several source from the internetz.
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Sources:
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https://git.cryhost.de/crycode/attiny85-radiohead-dht22-weather-sensor/-/tree/master
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*/
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// pin with the LED connected
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#define LED_PIN 4
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// blink time for the LED
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#define LED_TIME 200
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// pin of the DHT22 sensor
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#define DHT_PIN 1
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// the own RadioHead address
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#define RH_OWN_ADDR 0xca // 202
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// the server RadioHead address
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#define RH_SERVER_ADDR 0x01
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// RadioHead bitrate in bit/s
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#define RH_SPEED 1200
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// pins for the radio hardware
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#define RH_RX_PIN 5 // not used, set to a non-existent pin
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#define RH_TX_PIN 3
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#define RH_PTT_PIN 5 // not used, set to a non-existent pin
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#include <Arduino.h>
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#include <avr/sleep.h>
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#include <avr/wdt.h>
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#include <util/delay.h>
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// for watchdog wakeup
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// https://gist.github.com/dwhacks/8055287
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#ifndef cbi
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#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
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#endif
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#ifndef sbi
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#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
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#endif
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// DHT22 lib
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// not using the current adafruit dht library, because it eats too many memory
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#include "dht22.h"
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dht22 dht;
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#define RH_BUF_LEN 5
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uint8_t rh_buf[RH_BUF_LEN] = { 0x00, 0x00, 0x00, 0x00, 0x00 };
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// reduce the RadioHead max message length to save memory
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#define RH_ASK_MAX_MESSAGE_LEN RH_BUF_LEN
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// RadioHead
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#include <RH_ASK.h>
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#define MSG_START 0x00
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#define MSG_TEMP 0x01
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#define MSG_HUMID 0x02
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#define MSG_BAT 0x03
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#define MSG_ERR 0xee
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RH_ASK rh_driver(RH_SPEED, RH_RX_PIN, RH_TX_PIN, RH_PTT_PIN);
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// watchdog flag
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volatile boolean f_wdt = 1;
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// temp / humid toggle
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volatile uint8_t counter = 0;
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void gotoSleep(void);
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int getVcc();
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void setup() {
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// setup the LED pin
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pinMode(LED_PIN, OUTPUT);
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// init the DHT22
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dht_init(&dht, DHT_PIN);
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uint8_t num_blink = 3;
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if (!rh_driver.init()) {
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num_blink = 5;
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}
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// blink 3 times
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for (uint8_t i = 0; i < num_blink; i++) {
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digitalWrite(LED_PIN, HIGH);
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_delay_ms(LED_TIME);
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digitalWrite(LED_PIN, LOW);
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_delay_ms(LED_TIME);
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}
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// send start message
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rh_buf[0] = MSG_START;
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rh_send(1);
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setup_watchdog(6); // approximately 4 seconds sleep
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}
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// main loop
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void loop() {
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if (f_wdt) {
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f_wdt = 0;
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// turn on the LED
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digitalWrite(LED_PIN, HIGH);
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// temperature and humidity
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float t = 0;//float is 32bit = 1byte
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float h = 0;
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long battery = 0;
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if (counter % 4 == 0) {
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rh_buf[0] = MSG_BAT;
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battery = getVcc();
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memcpy(&rh_buf[1], &battery, 4);
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rh_send(RH_BUF_LEN);
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}else if (dht_read_data(&dht, &t, &h) == 1) {
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if (counter % 2 == 0) {
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rh_buf[0] = MSG_TEMP;
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memcpy(&rh_buf[1], &t, 4);
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} else if (counter % 2 == 1) {
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rh_buf[0] = MSG_HUMID;
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memcpy(&rh_buf[1], &h, 4);
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}
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rh_send(RH_BUF_LEN);
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} else {
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// error message
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rh_buf[0] = MSG_ERR;
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rh_send(1);
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}
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counter++;
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// turn off the LED
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digitalWrite(LED_PIN, LOW);
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system_sleep();
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//_delay_ms(1000);
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}
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}
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// function to send RadioHead messages from the buffer
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void rh_send(uint8_t len) {
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rh_driver.send((uint8_t *)rh_buf, len);
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rh_driver.waitPacketSent();
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}
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ISR(WDT_vect)
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{
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f_wdt = 1; // set global flag
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}
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/* set system into the sleep state
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system wakes up when watchdog is timed out
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*/
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void system_sleep() {
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//cbi(ADCSRA, ADEN); // switch Analog to Digitalconverter OFF
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set_sleep_mode(SLEEP_MODE_PWR_DOWN); // sleep mode is set here
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sleep_enable();
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sleep_mode(); // System sleeps here
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sleep_disable(); // System continues execution here when watchdog timed out
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//sbi(ADCSRA, ADEN); // switch Analog to Digitalconverter ON
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}
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/* 0=16ms, 1=32ms,2=64ms,3=128ms,4=250ms,5=500ms
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6=1 sec,7=2 sec, 8=4 sec, 9= 8sec
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*/
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void setup_watchdog(int ii) {
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byte bb;
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int ww;
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if (ii > 9 ) ii = 9;
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bb = ii & 7;
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if (ii > 7) bb |= (1 << 5);
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bb |= (1 << WDCE);
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ww = bb;
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MCUSR &= ~(1 << WDRF);
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// start timed sequence
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WDTCR |= (1 << WDCE) | (1 << WDE);
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// set new watchdog timeout value
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WDTCR = bb;
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WDTCR |= _BV(WDIE);
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}
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/**
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From https://github.com/cano64/ArduinoSystemStatus/blob/master/SystemStatus.cpp
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*/
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int getVcc() {
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//reads internal 1V1 reference against VCC
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ADMUX = _BV(MUX3) | _BV(MUX2); // For ATtiny85/45
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_delay_ms(5);; // Wait for Vref to settle
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ADCSRA |= _BV(ADSC); // Convert
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while (bit_is_set(ADCSRA, ADSC));
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uint8_t low = ADCL;
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unsigned int val = (ADCH << 8) | low;
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//discard previous result
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ADCSRA |= _BV(ADSC); // Convert
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while (bit_is_set(ADCSRA, ADSC));
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low = ADCL;
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val = (ADCH << 8) | low;
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return ((long)1024 * 1100) / val;
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}
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