Initial commit

.gitignore

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+.pio

.travis.yml

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+# Continuous Integration (CI) is the practice, in software
+# engineering, of merging all developer working copies with a shared mainline
+# several times a day < https://docs.platformio.org/page/ci/index.html >
+#
+# Documentation:
+#
+# * Travis CI Embedded Builds with PlatformIO
+#   < https://docs.travis-ci.com/user/integration/platformio/ >
+#
+# * PlatformIO integration with Travis CI
+#   < https://docs.platformio.org/page/ci/travis.html >
+#
+# * User Guide for `platformio ci` command
+#   < https://docs.platformio.org/page/userguide/cmd_ci.html >
+#
+#
+# Please choose one of the following templates (proposed below) and uncomment
+# it (remove "# " before each line) or use own configuration according to the
+# Travis CI documentation (see above).
+#
+
+
+#
+# Template #1: General project. Test it using existing `platformio.ini`.
+#
+
+# language: python
+# python:
+#     - "2.7"
+#
+# sudo: false
+# cache:
+#     directories:
+#         - "~/.platformio"
+#
+# install:
+#     - pip install -U platformio
+#     - platformio update
+#
+# script:
+#     - platformio run
+
+
+#
+# Template #2: The project is intended to be used as a library with examples.
+#
+
+# language: python
+# python:
+#     - "2.7"
+#
+# sudo: false
+# cache:
+#     directories:
+#         - "~/.platformio"
+#
+# env:
+#     - PLATFORMIO_CI_SRC=path/to/test/file.c
+#     - PLATFORMIO_CI_SRC=examples/file.ino
+#     - PLATFORMIO_CI_SRC=path/to/test/directory
+#
+# install:
+#     - pip install -U platformio
+#     - platformio update
+#
+# script:
+#     - platformio ci --lib="." --board=ID_1 --board=ID_2 --board=ID_N

include/README

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+
+This directory is intended for project header files.
+
+A header file is a file containing C declarations and macro definitions
+to be shared between several project source files. You request the use of a
+header file in your project source file (C, C++, etc) located in `src` folder
+by including it, with the C preprocessing directive `#include'.
+
+```src/main.c
+
+#include "header.h"
+
+int main (void)
+{
+ ...
+}
+```
+
+Including a header file produces the same results as copying the header file
+into each source file that needs it. Such copying would be time-consuming
+and error-prone. With a header file, the related declarations appear
+in only one place. If they need to be changed, they can be changed in one
+place, and programs that include the header file will automatically use the
+new version when next recompiled. The header file eliminates the labor of
+finding and changing all the copies as well as the risk that a failure to
+find one copy will result in inconsistencies within a program.
+
+In C, the usual convention is to give header files names that end with `.h'.
+It is most portable to use only letters, digits, dashes, and underscores in
+header file names, and at most one dot.
+
+Read more about using header files in official GCC documentation:
+
+* Include Syntax
+* Include Operation
+* Once-Only Headers
+* Computed Includes
+
+https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html

lib/README

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+
+This directory is intended for project specific (private) libraries.
+PlatformIO will compile them to static libraries and link into executable file.
+
+The source code of each library should be placed in a an own separate directory
+("lib/your_library_name/[here are source files]").
+
+For example, see a structure of the following two libraries `Foo` and `Bar`:
+
+|--lib
+|  |
+|  |--Bar
+|  |  |--docs
+|  |  |--examples
+|  |  |--src
+|  |     |- Bar.c
+|  |     |- Bar.h
+|  |  |- library.json (optional, custom build options, etc) https://docs.platformio.org/page/librarymanager/config.html
+|  |
+|  |--Foo
+|  |  |- Foo.c
+|  |  |- Foo.h
+|  |
+|  |- README --> THIS FILE
+|
+|- platformio.ini
+|--src
+   |- main.c
+
+and a contents of `src/main.c`:
+```
+#include <Foo.h>
+#include <Bar.h>
+
+int main (void)
+{
+  ...
+}
+
+```
+
+PlatformIO Library Dependency Finder will find automatically dependent
+libraries scanning project source files.
+
+More information about PlatformIO Library Dependency Finder
+- https://docs.platformio.org/page/librarymanager/ldf.html

lib/SHT2x/SHT2x.cpp

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+/*
+ SHT2x - Humidity Library for Arduino.
+ Get humidity and temperature from the HTU21D/SHT2x sensors.
+
+ Hardware Setup:
+ Attach the SDA pin to A4, SCL to A5.
+
+ Software:
+ Call SHT2x.Begin() in setup.
+ SHT2x.ReadHumidity() will return a float containing the humidity. Ex: 54.7
+ SHT2x.ReadTemperature() will return a float containing the temperature in Celsius. Ex: 24.1
+ SHT2x.SetResolution(byte: 0b.76543210) sets the resolution of the readings.
+
+  Copyright (C) 2015  Nuno Chaveiro  nchaveiro[at]gmail.com  Lisbon, Portugal
+  Copyright (C) 2020  Thomas Buck <thomas@xythobuz.de>
+*/
+
+#include <Wire.h>
+#include "SHT2x.h"
+
+SHT2x::SHT2x(uint8_t _addr, TwoWire* _wire) {
+    addr = _addr;
+    wire = _wire;
+}
+
+void SHT2x::begin(void) {
+    wire->begin();
+}
+
+bool SHT2x::GetAlive(void) {
+    uint16_t r = readSensor(TRIGGER_TEMP_MEASURE_HOLD);
+    if ((r == ERROR_TIMEOUT) || (r == ERROR_CRC)) {
+        return false;
+    }
+    return true;
+}
+
+/**********************************************************
+ * GetHumidity
+ *  Gets the current humidity from the sensor.
+ *
+ * @return float - The relative humidity in %RH
+ **********************************************************/
+float SHT2x::GetHumidity(void) {
+    return (-6.0 + 125.0 / 65536.0 * (float)(readSensor(TRIGGER_HUMD_MEASURE_HOLD)));
+}
+
+/**********************************************************
+ * GetTemperature
+ *  Gets the current temperature from the sensor.
+ *
+ * @return float - The temperature in Deg C
+ **********************************************************/
+float SHT2x::GetTemperature(void) {
+    return (-46.85 + 175.72 / 65536.0 * (float)(readSensor(TRIGGER_TEMP_MEASURE_HOLD)));
+}
+
+/**********************************************************
+ * Sets the sensor resolution to one of four levels:
+ *  0/0 = 12bit RH, 14bit Temp
+ *  0/1 = 8bit RH, 12bit Temp
+ *  1/0 = 10bit RH, 13bit Temp
+ *  1/1 = 11bit RH, 11bit Temp
+ *  Power on default is 0/0
+ **********************************************************/
+void SHT2x::setResolution(uint8_t resolution) {
+    uint8_t userRegister = read_user_register(); //Go get the current register state
+    userRegister &= B01111110; //Turn off the resolution bits
+    resolution &= B10000001; //Turn off all other bits but resolution bits
+    userRegister |= resolution; //Mask in the requested resolution bits
+
+    //Request a write to user register
+    wire->beginTransmission(addr);
+    wire->write(WRITE_USER_REG); //Write to the user register
+    wire->write(userRegister); //Write the new resolution bits
+    wire->endTransmission();
+}
+
+uint8_t SHT2x::read_user_register(void) {
+    uint8_t userRegister;
+
+    //Request the user register
+    wire->beginTransmission(addr);
+    wire->write(READ_USER_REG); //Read the user register
+    wire->endTransmission();
+
+    //Read result
+    wire->requestFrom(addr, 1);
+
+    userRegister = wire->read();
+
+    return userRegister;
+}
+
+uint16_t SHT2x::readSensor(uint8_t command) {
+    uint16_t result;
+
+    wire->beginTransmission(addr); //begin
+    wire->write(command);                     //send the pointer location
+    wire->endTransmission();                  //end
+
+    //Hang out while measurement is taken. 50mS max, page 4 of datasheet.
+    delay(55);
+
+    //Comes back in three bytes, data(MSB) / data(LSB) / Checksum
+    wire->requestFrom(addr, 3);
+
+    //Wait for data to become available
+    int counter = 0;
+    while (wire->available() < 3) {
+        counter++;
+        delay(1);
+        if(counter > 100) return ERROR_TIMEOUT; //Error timout
+    }
+
+    //Store the result
+    result = ((wire->read()) << 8);
+    result |= wire->read();
+    //Check validity
+    uint8_t checksum = wire->read();
+    if(check_crc(result, checksum) != 0) return(ERROR_CRC); //Error checksum
+    //sensorStatus = rawTemperature & 0x0003; //get status bits
+    result &= ~0x0003;   // clear two low bits (status bits)
+    return result;
+}
+
+//Give this function the 2 byte message (measurement) and the check_value byte from the HTU21D
+//If it returns 0, then the transmission was good
+//If it returns something other than 0, then the communication was corrupted
+//From: http://www.nongnu.org/avr-libc/user-manual/group__util__crc.html
+//POLYNOMIAL = 0x0131 = x^8 + x^5 + x^4 + 1 : http://en.wikipedia.org/wiki/Computation_of_cyclic_redundancy_checks
+#define SHIFTED_DIVISOR 0x988000 // This is the 0x0131 polynomial shifted to farthest left of three bytes
+
+uint8_t SHT2x::check_crc(uint16_t message_from_sensor, uint8_t check_value_from_sensor) {
+    // Pad with 8 bits because we have to add in the check value
+    uint32_t remainder = (uint32_t)message_from_sensor << 8;
+
+    // Add on the check value
+    remainder |= check_value_from_sensor;
+    uint32_t divsor = (uint32_t)SHIFTED_DIVISOR;
+
+    // Operate on only 16 positions of max 24.
+    // The remaining 8 are our remainder and should be zero when we're done.
+    for (int i = 0; i < 16; i++) {
+        // Check if there is a one in the left position
+        if (remainder & ((uint32_t)1 << (23 - i))) {
+            remainder ^= divsor;
+        }
+
+        // Rotate the divsor max 16 times so that we have 8 bits left of a remainder
+        divsor >>= 1;
+    }
+
+    return (uint8_t)remainder;
+}
+

lib/SHT2x/SHT2x.h

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+/*
+ SHT2x - Humidity Library for Arduino.
+ Get humidity and temperature from the HTU21D/SHT2x sensors.
+
+ Hardware Setup:
+ Attach the SDA pin to A4, SCL to A5.
+
+ Software:
+ Call SHT2x.Begin() in setup.
+ SHT2x.ReadHumidity() will return a float containing the humidity. Ex: 54.7
+ SHT2x.ReadTemperature() will return a float containing the temperature in Celsius. Ex: 24.1
+ SHT2x.SetResolution(byte: 0b.76543210) sets the resolution of the readings.
+
+  Copyright (C) 2015  Nuno Chaveiro  nchaveiro[at]gmail.com  Lisbon, Portugal
+  Copyright (C) 2020  Thomas Buck <thomas@xythobuz.de>
+*/
+
+#if defined(ARDUINO) && ARDUINO >= 100
+ #include "Arduino.h"
+#else
+ #include "WProgram.h"
+#endif
+
+#include <Wire.h>
+
+#ifndef SHT2X_H
+#define SHT2X_H
+
+// Unshifted 7-bit I2C address for the sensor
+#define HTDU21D_ADDRESS             0x40
+
+#define TRIGGER_TEMP_MEASURE_HOLD   0xE3
+#define TRIGGER_HUMD_MEASURE_HOLD   0xE5
+#define TRIGGER_TEMP_MEASURE_NOHOLD 0xF3
+#define TRIGGER_HUMD_MEASURE_NOHOLD 0xF5
+
+#define WRITE_USER_REG              0xE6
+#define READ_USER_REG               0xE7
+#define SOFT_RESET                  0xFE
+
+#define ERROR_CRC                   998
+#define ERROR_TIMEOUT               999
+
+class SHT2x {
+    public:
+        SHT2x(uint8_t _addr = HTDU21D_ADDRESS, TwoWire* _wire = &Wire);
+        void     begin();
+        bool     GetAlive(void);
+        float    GetHumidity(void);
+        float    GetTemperature(void);
+        void     setResolution(uint8_t resBits);
+        uint8_t  read_user_register(void);
+        uint16_t readSensor(uint8_t command);
+
+    private:
+        uint8_t  check_crc(uint16_t message_from_sensor, uint8_t check_value_from_sensor);
+
+        uint8_t addr;
+        TwoWire* wire;
+};
+
+#endif
+

platformio.ini

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+;PlatformIO Project Configuration File
+;
+;   Build options: build flags, source filter
+;   Upload options: custom upload port, speed and extra flags
+;   Library options: dependencies, extra library storages
+;   Advanced options: extra scripting
+;
+; Please visit documentation for the other options and examples
+; https://docs.platformio.org/page/projectconf.html
+
+[env:esp01]
+platform = espressif8266@2.3.2
+board = esp01
+framework = arduino
+lib_deps =
+    Wire
+    ESP8266 Influxdb@1.3.0
+    Adafruit Unified Sensor@1.1.1
+    Adafruit BME280 Library@2.0.0
+

src/main.cpp

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+#include <Arduino.h>
+#include <Wire.h>
+#include <ESP8266WiFi.h>
+#include <InfluxDb.h>
+#include <ESP8266WebServer.h>
+#include <ESP8266mDNS.h>
+#include <Adafruit_BME280.h>
+#include <SHT2x.h>
+
+const char* sensor_location = "SENSOR_NAME_GOES_HERE";
+
+const char* ssid = "YOUR_SSID_HERE";
+const char* password = "YOUR_PASS_HERE";
+
+#define INFLUXDB_HOST "INFLUX_DB_SERVER_IP_HERE"
+#define INFLUXDB_PORT 8086
+#define INFLUXDB_DATABASE "INFLUX_DB_DATABASE_NAME_HERE"
+
+#define SENSOR_HOSTNAME_PREFIX "ESP-"
+
+Influxdb influx(INFLUXDB_HOST, INFLUXDB_PORT);
+ESP8266WebServer server(80);
+TwoWire Wire2;
+SHT2x sht(HTDU21D_ADDRESS, &Wire2);
+Adafruit_BME280 bme;
+bool found_bme = false;
+bool found_sht = false;
+
+void handleRoot() {
+    String message = "ESP8266 BME280 Sensor";
+    message += "\n\nLocation: ";
+    message += sensor_location;
+    message += "\nMAC: ";
+    message += WiFi.macAddress();
+
+    if (found_bme) {
+        message += "\n\nBME280:";
+        message += "\nTemperature: ";
+        message += String(bme.readTemperature());
+        message += "\nHumidity: ";
+        message += String(bme.readHumidity());
+        message += "\nPressure: ";
+        message += String(bme.readPressure());
+    }
+
+    if (found_sht) {
+        message += "\n\nSHT21:";
+        message += "\nTemperature: ";
+        message += String(sht.GetTemperature());
+        message += "\nHumidity: ";
+        message += String(sht.GetHumidity());
+    }
+
+    if ((!found_bme) && (!found_sht)) {
+        message += "\n\nNo Sensor available!";
+    }
+
+    message += "\n";
+    server.send(200, "text/plain", message);
+}
+
+void setup() {
+    pinMode(1, OUTPUT);
+    digitalWrite(1, LOW); // LED on
+    delay(500);
+    digitalWrite(1, HIGH); // LED off
+    delay(500);
+    digitalWrite(1, LOW); // LED on
+    delay(500);
+    digitalWrite(1, HIGH); // LED off
+    delay(500);
+
+    Wire2.begin(2, 0);
+    found_bme = (!bme.begin(0x76, &Wire2)) ? false : true;
+    found_sht = sht.GetAlive();
+
+    if ((!found_bme) && (!found_sht)) {
+        // no sensor available
+        while (1) {
+            digitalWrite(1, !digitalRead(1));
+            delay(100);
+        }
+    }
+
+    String hostname = SENSOR_HOSTNAME_PREFIX;
+    hostname += sensor_location;
+    WiFi.hostname(hostname);
+
+    WiFi.mode(WIFI_STA);
+    WiFi.begin(ssid, password);
+
+    MDNS.begin(hostname);
+
+    while (WiFi.status() != WL_CONNECTED) {
+        delay(250);
+        digitalWrite(1, !digitalRead(1));
+    }
+
+    influx.setDb(INFLUXDB_DATABASE);
+
+    server.on("/", handleRoot);
+    server.begin();
+}
+
+#define SERVER_HANDLE_INTERVAL 10 // in ms
+#define DB_WRITE_INTERVAL (30 * 1000) // in ms
+#define LED_BLINK_INTERVAL (2 * 1000) // in ms
+
+unsigned long last_server_handle_time = 0;
+unsigned long last_db_write_time = 0;
+unsigned long last_led_blink_time = 0;
+
+void loop() {
+    unsigned long time = millis();
+
+    if ((time - last_server_handle_time) >= SERVER_HANDLE_INTERVAL) {
+        last_server_handle_time = time;
+
+        server.handleClient();
+        MDNS.update();
+    }
+
+    if ((time - last_db_write_time) >= DB_WRITE_INTERVAL) {
+        last_db_write_time = time;
+
+        if (found_bme) {
+            InfluxData measurement("environment");
+            measurement.addTag("location", sensor_location);
+            measurement.addTag("device", WiFi.macAddress());
+            measurement.addTag("sensor", "bme280");
+
+            measurement.addValue("temperature", bme.readTemperature());
+            measurement.addValue("pressure", bme.readPressure());
+            measurement.addValue("humidity", bme.readHumidity());
+
+            boolean success = influx.write(measurement);
+            if (!success) {
+                digitalWrite(1, !digitalRead(1));
+            }
+        }
+
+        if (found_sht) {
+            InfluxData measurement("environment");
+            measurement.addTag("location", sensor_location);
+            measurement.addTag("device", WiFi.macAddress());
+            measurement.addTag("sensor", "sht21");
+
+            measurement.addValue("temperature", sht.GetTemperature());
+            measurement.addValue("humidity", sht.GetHumidity());
+
+            boolean success = influx.write(measurement);
+            if (!success) {
+                digitalWrite(1, !digitalRead(1));
+            }
+        }
+    }
+
+    if ((time - last_led_blink_time) >= LED_BLINK_INTERVAL) {
+        last_led_blink_time = time;
+
+        digitalWrite(1, !digitalRead(1));
+    }
+}
+

test/README

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+
+This directory is intended for PIO Unit Testing and project tests.
+
+Unit Testing is a software testing method by which individual units of
+source code, sets of one or more MCU program modules together with associated
+control data, usage procedures, and operating procedures, are tested to
+determine whether they are fit for use. Unit testing finds problems early
+in the development cycle.
+
+More information about PIO Unit Testing:
+- https://docs.platformio.org/page/plus/unit-testing.html