Cara mengubah IPAddress menjadi char[] di Arduino
– class IPAddress memiliki fungsi toString untuk mengubah ke String
– class String memiliki fungsi c_str untuk mengubah ke pointer character

Contoh:

char ip_address_string[16];
sprintf(ip_address_string, "%s", WiFi.localIP().toString().c_str());

Referensi:

• Adafruit HTU21D-F Temperature & Humidity Sensor Breakout Board

Contoh Program untuk ESP32

// library: https://github.com/adafruit/Adafruit_HTU21DF_Library
#define I2C_SDA 15
#define I2C_SCL 13

#include <Wire.h>
#include "Adafruit_HTU21DF.h"

// Connect Vin to 3-5VDC
// Connect GND to ground
// Connect SCL to I2C clock pin (13)
// Connect SDA to I2C data pin (15)

Adafruit_HTU21DF htu = Adafruit_HTU21DF();

void setup() {
  Serial.begin(115200);
  Serial.println("HTU21D-F test");
  Wire.begin(I2C_SDA, I2C_SCL);
  if (!htu.begin()) {
    Serial.println("Couldn't find sensor!");
    while (1);
  }
}

void loop() {
  float temp = htu.readTemperature();
  float rel_hum = htu.readHumidity();
  Serial.print("Temp: "); Serial.print(temp); Serial.print(" C");
  Serial.print("\t\t");
  Serial.print("Humidity: "); Serial.print(rel_hum); Serial.println(" \%");
  delay(500);
}

Contoh kode ESP32 untuk menghubungkan MCP9808 ke ThingsBoard. Kode ini menggunakan library MCP9808 dari Adafruit

// CJMCU-9808
// Adafruit MCP9808 Library https://github.com/adafruit/Adafruit_MCP9808_Library

#include <WiFi.h>           // WiFi control for ESP32
#include <ThingsBoard.h>    // ThingsBoard SDK
#include <Wire.h>
#include "Adafruit_MCP9808.h"
#include <Arduino.h>
#include <Wire.h>

Adafruit_MCP9808 tempsensor = Adafruit_MCP9808();

// WiFi access point
#define WIFI_AP_NAME        "WIFI_AP_NAME"
// WiFi password
#define WIFI_PASSWORD       "WIFI_PASSWORD"
#define TOKEN               "THINGSBOARD_TOKEN"

#define BUILTIN_LED 22
// ThingsBoard server instance.
#define THINGSBOARD_SERVER  "192.168.0.90"

#define I2C_SDA 15
#define I2C_SCL 13

// Initialize ThingsBoard client
WiFiClient espClient;
// Initialize ThingsBoard instance
ThingsBoard tb(espClient);
// the Wifi radio's status
int status = WL_IDLE_STATUS;

// main application loop delay (ms)
int quant = 20;

// Period of sending a temperature/humidity data.
int send_delay = 2000;

// Time passed after telemetry data was sent, milliseconds.
int send_passed = 0;

char mac_str[20]; // storing MAC address string
byte mac_byte[6]; // storing MAC address bytes

int led_counter = 0; //blinking built int led

void setup() {
  pinMode(BUILTIN_LED, OUTPUT);
  // put your setup code here, to run once:
  Serial.begin(115200);
  delay(1000);

  //wait for serial connection to open (only necessary on some boards)
  while (!Serial);

  Wire.begin(I2C_SDA, I2C_SCL);

  I2C_Scan() ; // just for verifying

  if (!tempsensor.begin(0x18)) {
    Serial.println("Couldn't find MCP9808! Check your connections and verify the address is correct.");
    while (1);
  }
  tempsensor.setResolution(3);

  WiFi.begin(WIFI_AP_NAME, WIFI_PASSWORD);
  InitWiFi();
  WiFi.macAddress(mac_byte);
  sprintf(mac_str, "%02x%02x%02x%02x%02x%02x", mac_byte[0], mac_byte[1], mac_byte[2], mac_byte[3], mac_byte[4], mac_byte[5]);
  Serial.print("ESP board MAC address:  ");
  Serial.println(WiFi.macAddress());
  Serial.print("ESP board  IP address: ");
  Serial.println(WiFi.localIP());
}

void loop() {
  float temperature = 25;
  float pressure = 0;
  float humidity = 60; // default humidity
  float co2 = 0;
  float tvoc = 0;

  delay(quant);
  send_passed += quant;

  // Reconnect to WiFi, if needed
  if (WiFi.status() != WL_CONNECTED) {
    reconnect();
    return;
  }

  // Reconnect to ThingsBoard, if needed
  if (!tb.connected()) {
    // Connect to the ThingsBoard
    Serial.print("Connecting to: ");
    Serial.print(THINGSBOARD_SERVER);
    Serial.print(" with token ");
    Serial.println(TOKEN);
    if (!tb.connect(THINGSBOARD_SERVER, TOKEN)) {
      Serial.println("Failed to connect");
      return;
    }
  }

  // Check if it is a time to send sensor data
  if (send_passed > send_delay) {
//    Serial.println("wake up MCP9808.... "); // wake up MCP9808 - power consumption ~200 mikro Ampere
    tempsensor.wake();   // wake up, ready to read!

    // Read and print out the temperature, also shows the resolution mode used for reading.
    //    Serial.print("Resolution in mode: ");
    //    Serial.println (tempsensor.getResolution());
    float c = tempsensor.readTempC();
    //    Serial.print("Temp: ");
    //    Serial.print(c, 4);
    //    Serial.print("*C\t and ");
    //    Serial.println("Shutdown MCP9808.... ");
    tempsensor.shutdown_wake(1); // shutdown MSP9808 - power consumption ~0.1 mikro Ampere, stops temperature sampling
//    Serial.println("");

    Serial.print("Sending telemetry data...");
    Serial.print("Temp ");
    Serial.print(c);
    Serial.println(" ");
    tb.sendTelemetryFloat("temperature", c);
    send_passed = 0;
  }

  // Process messages
  tb.loop();

  led_counter++; // LED blink at 1 Hz
  if (led_counter > 50) {
    led_counter = 0;
  }
  if (led_counter > 25) {
    digitalWrite(BUILTIN_LED , LOW);
  } else {
    digitalWrite(BUILTIN_LED , HIGH);
  }
}

void I2C_Scan() {
  byte error, address;

  int nDevices;
  Serial.println("I2C Scanning...");
  nDevices = 0;
  for (address = 1; address < 127; address++ ) {
    Wire.beginTransmission(address);
    error = Wire.endTransmission();
    if (error == 0) {
      Serial.print("I2C device found at address 0x");
      if (address < 16) {
        Serial.print("0");
      }
      Serial.println(address, HEX);
      nDevices++;
    }
    else if (error == 4) {
      Serial.print("Unknow error at address 0x");
      if (address < 16) {
        Serial.print("0");
      }
      Serial.println(address, HEX);
    }
  }
  if (nDevices == 0) {
    Serial.println("No I2C devices found\n");
  }
  else {
    Serial.println("done\n");
  }
}

void InitWiFi()
{
  Serial.println("Connecting to AP ...");
  // attempt to connect to WiFi network

  WiFi.begin(WIFI_AP_NAME, WIFI_PASSWORD);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("Connected to AP");
}

void reconnect() {
  // Loop until we're reconnected
  status = WiFi.status();
  if ( status != WL_CONNECTED) {
    WiFi.begin(WIFI_AP_NAME, WIFI_PASSWORD);
    while (WiFi.status() != WL_CONNECTED) {
      delay(500);
      Serial.print(".");
    }
    Serial.println("Connected to AP");
  }
}

update: ditambah dengan watch dog timer

// CJMCU-9808
// Adafruit MCP9808 Library https://github.com/adafruit/Adafruit_MCP9808_Library

#include <WiFi.h>           // WiFi control for ESP32
#include <ThingsBoard.h>    // ThingsBoard SDK
#include <Wire.h>
#include "Adafruit_MCP9808.h"
#include <Arduino.h>
#include <Wire.h>
#include <esp_task_wdt.h>

Adafruit_MCP9808 tempsensor = Adafruit_MCP9808();

#define WDT_TIMEOUT 60
#define WIFI_AP_NAME        "abc" // WiFi access point
#define WIFI_PASSWORD       "123"
#define TOKEN               "jiowre43278feowjk4"

#define BUILTIN_LED 22
// ThingsBoard server instance.
#define THINGSBOARD_SERVER  "192.168.0.114"

#define I2C_SDA 15
#define I2C_SCL 13

// Initialize ThingsBoard client
WiFiClient espClient;
// Initialize ThingsBoard instance
ThingsBoard tb(espClient);
// the Wifi radio's status
int status = WL_IDLE_STATUS;

// main application loop delay (ms)
int quant = 20;

// Period of sending a temperature/humidity data.
int send_delay = 2000;

// Time passed after telemetry data was sent, milliseconds.
int send_passed = 0;

char mac_str[20]; // storing MAC address string
byte mac_byte[6]; // storing MAC address bytes

int led_counter = 0; //blinking built int led

void setup() {
  pinMode(BUILTIN_LED, OUTPUT);
  // put your setup code here, to run once:
  Serial.begin(115200);
  delay(1000);
  Serial.print(__FILE__);
  //wait for serial connection to open (only necessary on some boards)
  while (!Serial);

  Wire.begin(I2C_SDA, I2C_SCL);

  I2C_Scan() ; // just for verifying

  if (!tempsensor.begin(0x18)) {
    Serial.println("Couldn't find MCP9808! Check your connections and verify the address is correct.");
    while (1);
  }
  tempsensor.setResolution(3);

  WiFi.begin(WIFI_AP_NAME, WIFI_PASSWORD);
  InitWiFi();
  WiFi.macAddress(mac_byte);
  sprintf(mac_str, "%02x%02x%02x%02x%02x%02x", mac_byte[0], mac_byte[1], mac_byte[2], mac_byte[3], mac_byte[4], mac_byte[5]);
  Serial.print("ESP board MAC address:  ");
  Serial.println(WiFi.macAddress());
  Serial.print("ESP board  IP address: ");
  Serial.println(WiFi.localIP());

  // setup WDT
  esp_task_wdt_init(WDT_TIMEOUT, true); //enable panic so ESP32 restarts
  esp_task_wdt_add(NULL); //add current thread to WDT watch

}

void loop() {
  float temperature = 25;
  float pressure = 0;
  float humidity = 60; // default humidity
  float co2 = 0;
  float tvoc = 0;

  delay(quant);
  send_passed += quant;

  // Reconnect to WiFi, if needed
  if (WiFi.status() != WL_CONNECTED) {
    reconnect();
    sleep(5); // wait to reconnect
  }

  // Reconnect to ThingsBoard, if needed
  if (!tb.connected()) {
    // Connect to the ThingsBoard
    Serial.print("Connecting to: ");
    Serial.print(THINGSBOARD_SERVER);
    Serial.print(" with token ");
    Serial.println(TOKEN);
    if (!tb.connect(THINGSBOARD_SERVER, TOKEN)) {
      Serial.println("Failed to connect");
      return;
    }
  }

  // Check if it is a time to send sensor data
  if (send_passed > send_delay) {
    //    Serial.println("wake up MCP9808.... "); // wake up MCP9808 - power consumption ~200 mikro Ampere
    tempsensor.wake();   // wake up, ready to read!

    // Read and print out the temperature, also shows the resolution mode used for reading.
    //    Serial.print("Resolution in mode: ");
    //    Serial.println (tempsensor.getResolution());
    float c = tempsensor.readTempC();
    //    Serial.print("Temp: ");
    //    Serial.print(c, 4);
    //    Serial.print("*C\t and ");
    //    Serial.println("Shutdown MCP9808.... ");
    tempsensor.shutdown_wake(1); // shutdown MSP9808 - power consumption ~0.1 mikro Ampere, stops temperature sampling
    //    Serial.println("");

    Serial.print("Sending telemetry data...");
    Serial.print("Temp ");
    Serial.print(c);
    Serial.println(" ");
    tb.sendTelemetryFloat("temperature", c);
    send_passed = 0;
    esp_task_wdt_reset(); // WDT reset setelah berhasil mengirim data
  }

  // Process messages
  tb.loop();

  led_counter++; // LED blink at 1 Hz
  if (led_counter > 50) {
    led_counter = 0;
  }
  if (led_counter > 25) {
    digitalWrite(BUILTIN_LED , LOW);
  } else {
    digitalWrite(BUILTIN_LED , HIGH);
  }
}

void I2C_Scan() {
  byte error, address;

  int nDevices;
  Serial.println("I2C Scanning...");
  nDevices = 0;
  for (address = 1; address < 127; address++ ) {
    Wire.beginTransmission(address);
    error = Wire.endTransmission();
    if (error == 0) {
      Serial.print("I2C device found at address 0x");
      if (address < 16) {
        Serial.print("0");
      }
      Serial.println(address, HEX);
      nDevices++;
    }
    else if (error == 4) {
      Serial.print("Unknow error at address 0x");
      if (address < 16) {
        Serial.print("0");
      }
      Serial.println(address, HEX);
    }
  }
  if (nDevices == 0) {
    Serial.println("No I2C devices found\n");
  }
  else {
    Serial.println("done\n");
  }
}

void InitWiFi()
{
  Serial.println("Connecting to AP ...");
  // attempt to connect to WiFi network

  WiFi.begin(WIFI_AP_NAME, WIFI_PASSWORD);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("Connected to AP");
}

void reconnect() {
  // Loop until we're reconnected
  status = WiFi.status();
  if ( status != WL_CONNECTED) {
    WiFi.begin(WIFI_AP_NAME, WIFI_PASSWORD);
    while (WiFi.status() != WL_CONNECTED) {
      delay(500);
      Serial.print(".");
    }
    Serial.println("Connected to AP");
  }
}

Referensi:

• https://learn.adafruit.com/adafruit-mcp9808-precision-i2c-temperature-sensor-guide/pinouts
• Mircrochip Datasheet MCP9808
• Adafruit MCP9808

Mikrokontroler seperti ATmega328 dapat diproteksi dengan memprogram fuse bit pada mikrokontroler tersebut. Pemrograman fuse bit mesti dilakukan menggunakan ISP (In System Programming) atau High Voltage Programming, jadi tidak dapat menggunakan port USB pada Arduino Nano / UNO.

Namun demikian proteksi ini dapat juga dibypass dengan menggunakan alat khusus.

Referensi

• Copy Protection in Modern Microcontrollers
• How to protect my program in ATmega328
• How to lock ATmega328P to disable sketch read
• ATmega328 Software Protection and Verification

Ada pertanyaan:

misalnya saya beli stabilizer dengan 10 Kva dengan input voltage V = 150-240 volt dan output voltage 110v / 220v. Itu watt aman yg bisa kita pake brp watt ya ?

Jawaban singkat:

• Pada kondisi serba ideal, daya maksimum yang dapat dipakai adalah 10 kW = 10000 watt . Dalam prakteknya, stabilizer sebaiknya dipakai hanya pada beban 70% saja (7000 watt). Efisiensi stabilizer juga perlu diperhatikan, misal 90%. Jika beban induktif seperti motor atau pompa, perlu dikalikan lagi dengan faktor daya misalnya 0,8 .

Kondisi serba ideal ini adalah:

• beban 3 fasa seimbang, sehingga arus pada setiap fasa sama besarnya. Dalam prakteknya arus pada setiap fasa perlu dihitung / diukur.
• faktor daya = 1, dalam prakteknya tergantung sifat beban. Kalau beban induktif dapat dipakai faktor daya=0,8.
• Stabilizer dapat dipakai pada 100% beban, dalam prakteknya sekitar 70%
• Efisiensi stabilizer 100%, dalam prakteknya sekitar 90%

Contoh kasus

Beban seimbang, beban pompa listrik 3 fasa (induktif). Maka kemampuan maksimum: 10 kW x 0.7 x 0.7 x 0.9 = 4410 watt

Perlu diperhatikan bahwa stabilizer 10 kVA biasanya 3 fasa. Pada stabilizer 3 fasa 10 kVA, arus maksimum di setiap fasa adalah sekitar 15 ampere.

Perhitungannya:

10 kVA / 3 / 220 volt = 15.151 ampere

Jika arus pada suatu fasa melebihi 15 ampere, maka dapat merusak stabilizer tersebut. Untuk amannya, batasi arus pada 70% arus maksimum, jadi dibatasi pada 15 x 70% = 10.5 ampere.

Sebaiknya dipelajari dulu spesifikasi dari stabilizer yang dipakai, misal di artikel ini: https://www.indotara.co.id/catalog/Arakawa%20Catalog%20Full.pdf

• Task Dummy untuk FreeRTOS
• Percobaan Penjadwal Periodik Dengan FreeRTOS pada Arduino Nano
• Percobaan Penjadwal Periodik FreeRTOS dengan 2 task

Foto

Referensi

• Datasheet Countis (mmem.com.au) [Mirror Socomec_Countis_E13x]
• Socomec Countis E13X User Manual [socomec-countis-e13x-operation-user-s-manual-8]
• Socomec Countis E13 Logging Modbus Registers Map
• Industrial Communication RS485 Bus
• Socomec: Countis E04 Communication Table
• Socomec: Countis E06 Communication Table
• Socomec: Countis E13 Communication Table
• Countis M13 Manual

Berikut ini beberapa tajuk yang dapat diajarkan di kelas sistem embedded.

Embedded:
– mengukur memory usage di stack
– apa yang terjadi kalau stack terlalu kecil pada sebuah task
– apa yang terjadi jika suatu resource diakses bersamaan oleh beberapa buah task

Tools pada pengembangan sistem embedded
– GIT: source control
– Unit Testing

Tajuk advanced:
– keamanan sistem embedded
– kriptografi sederhana
– machine learning & sistem embedded

Tugas Perancangan:
– metodologi desain
– pemodelan sistem
– multi tasking
– benchmark komputasi di PC dan di mikrokontroler
– pengujian algoritma di PC dan mikrokontroler

Praktikum:
– pengolahan sinyal LTI
– kendali LTI
– kendali FSM
– kendali hybrid