Benny Estes
Published © LGPL

ESP8266 Sleeping Temperature Station

This is a project for a small temperature, humidity, and battery voltage monitor, so I can track what the weather is doing outside.

BeginnerShowcase (no instructions)3 hours1,495
ESP8266 Sleeping Temperature Station

Things used in this project

Hardware components

Wemos D1 Mini
Espressif Wemos D1 Mini
×1

Software apps and online services

Cayenne
myDevices Cayenne

Story

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Code

Code snippet #1

C/C++
// #define CAYENNE_DEBUG Serial
// #define CAYENNE_PRINT Serial
#include <Wire.h>
#include <CayenneMQTTESP8266.h>
#include <ESP8266WiFi.h>
#include <EEPROM.h>


RF_MODE(RF_NO_CAL) // tells the ESP to just turn on radio, no calibration which extra takes power

char ssid[] = "IoT";
char wifiPassword[] = "";

char username[] = "";
char password[] = "";
char clientID[] = "";

#define Address         0x45 // wire address for the SHT3x
#define eepromAddress   0 // where sleep cycle status is stored
#define voltPin         A0
#define sleepDisablePin D7

// resistor values for volt divider
// R1 = 11910;
// R2 = 3260;
// voltFactor = R2 / (R1 + R2);

float voltFactor = 0.212;
float voltage;

bool online;

unsigned long onlineTime;
unsigned long prevTime;
unsigned long time1;

unsigned int data[6];
unsigned int disco = 0;

byte buttonEnabled = 0;
byte sleepDisabled = 1;
byte sleepNow = 0;
byte restartChip = 0;

float cTemp = 0.0;
float fTemp = 0.0;
float humidity = 0.0;




void setup()
{
	pinMode(BUILTIN_LED, OUTPUT);
	pinMode(sleepDisablePin, INPUT_PULLUP);  // jumper for sleep override

	for (int i = 0; i < 3; i++)              // LED blinks to show booting
	{
		digitalWrite(BUILTIN_LED, 0);
		delay(100);
		digitalWrite(BUILTIN_LED, 1);
		delay(100);
	}

	Wire.begin();
	EEPROM.begin(512);                            // to store sleep state
	// Serial.begin(9600);

	// voltFactor = R2 / (R1 + R2);
	voltFactor = 0.212;                           // for voltage divider

	buttonEnabled = EEPROM.read(eepromAddress);   // checks if it is in a sleep cycle
	sleepDisabled = digitalRead(sleepDisablePin); // checks for sleep cycle bypass

	Cayenne.begin(username, password, clientID, ssid, wifiPassword);

	if (sleepDisabled == 0)                       // stops sleep cycle if jumper LOW
	{
		sleepNow = 0;
		buttonEnabled = 0;
		Cayenne.virtualWrite(0, 0, "digital_sensor", "d");          // sends sleep cycle status to sleep button on dashboard
	}

	time1 = millis();

} // setup


void loop()
{
	Cayenne.loop();

	if (millis() - time1 > 20000)    // loop to get & send data every 20 seconds
	{
		getTemp();
		execute();
	}

	if (online == true)              // blinks LED if online about every 1 sec
	{
		digitalWrite(BUILTIN_LED, LOW);
		delay(10);
		digitalWrite(BUILTIN_LED, HIGH);
	}
	else
	{
		digitalWrite(BUILTIN_LED, HIGH);
	}

} // loop


void getTemp()  // pulls temp & humidity via i2c per datasheet, gets voltage
{
	Wire.beginTransmission(Address);

	Wire.write(0x2C);
	Wire.write(0x06);

	Wire.endTransmission();
	delay(500);

	Wire.requestFrom(Address, 6);              // get data

	if (Wire.available() == 6)
	{
		data[0] = Wire.read();
		data[1] = Wire.read();
		data[2] = Wire.read();
		data[3] = Wire.read();
		data[4] = Wire.read();
		data[5] = Wire.read();
	}


	cTemp = ((((data[0] * 256.0) + data[1]) * 175) / 65535.0) - 45;
	fTemp = (cTemp * 1.8) + 32;
	humidity = ((((data[3] * 256.0) + data[4]) * 100) / 65535.0);


	voltage = (analogRead(voltPin) / 1024) * 3.3;
	voltage = voltage / voltFactor;
} // getTemp




void execute()
{
	time1 = millis();              // record transmit time

// temp, humidity, and batt voltage
	Cayenne.virtualWrite(5, fTemp, "Fahrenheit", "f");
	Cayenne.virtualWrite(6, humidity, "Percent", "p");
	Cayenne.virtualWrite(8, fTemp, "analog_sensor", "null");
	Cayenne.virtualWrite(9, humidity, "analog_sensor", "null");

	Cayenne.virtualWrite(7, voltage, "analog_sensor", "null");
	Cayenne.virtualWrite(10, voltage, "analog_sensor", "null");

// system info
	Cayenne.virtualWrite(23, disco, "counter", "null");

	int time2 = (millis() / 1000) / 60;
	Cayenne.virtualWrite(24, time2, "counter", "null");

	onlineTime = ((millis() - prevTime) / 1000) / 60;
	Cayenne.virtualWrite(25, onlineTime, "counter", "null");


	if (sleepNow == 1)                 // if sleep is active, chip sleeps after data transmit
	{
		ESP.deepSleep(1200000 * 1000); // sleeps for 20 min
	}

} // execute


CAYENNE_CONNECTED()
{
	online = true;
	prevTime = millis();

	if (buttonEnabled == 1)      // checks if sleep cycle active
	{
		Cayenne.virtualWrite(0, 1, "digital_sensor", "d");          // sends value of sleep to dashboard
		sleepNow = 1;
	}
}

CAYENNE_DISCONNECTED()
{
	online = false;
	disco++;      // record disconnect
}




CAYENNE_IN(0)  // sleep button
{
	sleepNow = getValue.asInt();

	if (sleepNow == 1)     // save sleep cycle status to eeprom to read after reboot
	{
		EEPROM.write(eepromAddress, 1);
		EEPROM.commit();
	}
	else
	{
		EEPROM.write(eepromAddress, 0);
		EEPROM.commit();
	}

}

CAYENNE_IN(1) // trigger chip restart
{
	restartChip = getValue.asInt();
	delay(1500);

	if (restartChip == 1)
	{
		Cayenne.virtualWrite(1, 0, "digital_sensor", "d");         // writes reboot button back low before restart
		delay(1500);

		ESP.restart();
	}

}

Credits

vapor83

Posted by Benny Estes

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