Weather

 

This is the temporary installation of my Anemometer & Wind Vane to test via RS-485 into a couple of ESP-32's. The outside temp is currently -30C so I'm not in any hurry to mount these up higher where they will be unobstructed!

Here is the pic of the 12V supply feeding a buck converter down to 5VDC to feed both ESP32's, one for the Anemometer and one for the Wind Vane. Buck converter in the centre under the white CAT5 cable that feeds 12VDC power to the devices and brings back 2 wires each RS485 to the RS485>TTL converters (top & bottom of photo). You can see one of the ESP32's with the green tape showing 00 on it.

You are supposed to be able to change the addresses on the devices (they all default to 1) so that they can share the same RS485 buss, but the documentation is sparse on these units and rather than take the chance that I 'brick' them, I'm leaving the addresses alone. Which means that I now have 3 devices (Anemometer, Wind Vane & Temperature/Humidity Sensor that are all RS485.

After receiving my Raspberry Pi Pico 2W's I started reading the documentation and found that the PIO function allows for additional UART's (it comes with 2), so I wrote a sketch to talk to 3 RS485>TTL boards from the 2 UARTs and 1 SoftwareSerial PIO-based UART

Here is a line diagram of the original circuit before I added the Pico, third TTL>RS485 board & Temp/Humidity Sensor

/* 

 *  TempHumidRS485_3.ino

 *  Robin Greig

 *  2025.02.17

 *  

 *  Reads the Temp & Humidity of RS485 device and prints it to Serial Monitor

 *  

 *  Using both UARTS and PIO-based UART to read 3 RS485 > TTL inputs

 *  mySerial1 = Rx / Pin 2 / GPIO 1 & Tx / Pin 1 / GPIO 0

 *  mySerial2 = Rx / Pin 7 / GPIO 5 & Tx / Pin 6 / GPIO 4

 *  mySerial3 = SerialPIO = Tx / Pin 11 / GPIO 8 & Rx / Pin 12 / GPIO 9

 *  

 *  Addint mqtt connectivity

 *  

 *  Based on the ModbusMaster example below

*/

#include <ModbusMaster.h>       //https://github.com/4-20ma/ModbusMaster

#include <SoftwareSerial.h>

#include <WiFi.h> 

#include <PubSubClient.h>

#include <string.h>

// Create a SoftwareSerial object to communicate with the MAX485 module

SoftwareSerial mySerial1(1, 0); // Rx-Pin 2-GPIO 1 & Tx-Pin 1-GPIO 0

SoftwareSerial mySerial2(5, 4); // Rx-Pin 2-GPIO 1 & Tx-Pin 1-GPIO 0

SerialPIO mySerial3(8, 9); // Tx-GPIO 8-Pin 11 & Rx-GPIO 12-Pin 10

//for SoftwareSerial PIO-based UART

// Create a ModbusMaster object

ModbusMaster node1;

ModbusMaster node2;

ModbusMaster node3;

// WiFi 

const char *ssid = "Calalta02"; // Enter your WiFi name 

const char *password = "Micr0s0ft2018";  // Enter WiFi password 

// MQTT Broker 

const char *mqtt_broker = "192.168.200.143"; 

const char *topic1 = "pico2w/00/temp1";

const char *topic2 = "pico2w/00/humid1";  

const char *topic3 = "pico2w/00/temp2";

const char *topic4 = "pico2w/00/humid2";  

const char *topic5 = "pico2w/00/temp3";

const char *topic6 = "pico2w/00/humid3";  

const int mqtt_port = 1883; 

WiFiClient espClient; 

PubSubClient client(espClient); 

float humidity1;

char humidChar1 [6];

float humidity2;

char humidChar2 [6];

float humidity3;

char humidChar3 [6];

float temperature1;

char tempChar1 [6];

float temperature2;

char tempChar2 [6];

float temperature3;

char tempChar3 [6];

void setup() {

  // Initialize serial communication for debugging

  Serial.begin(115200);

  // Initialize SoftwareSerial for Modbus communication

  mySerial1.begin(9600);

  mySerial2.begin(9600);

  mySerial3.begin(9600);

 

  // Initialize Modbus communication with the Modbus slave ID 1

  node1.begin(1, mySerial1);

  node2.begin(1, mySerial2);

  node3.begin(1, mySerial3);

  WiFi.begin(ssid, password); // connecting to the WiFi network 

  while (WiFi.status() != WL_CONNECTED) { 

      delay(500); 

      Serial.println("Connecting to WiFi.."); 

  } 

  Serial.println("Connected to the WiFi network"); 

  //connecting to a mqtt broker 

  client.setServer(mqtt_broker, mqtt_port); 

  while (!client.connected()) { 

      String client_id = "pico2w-00 > "; 

      client_id += String(WiFi.macAddress());

      Serial.printf("The client %s is connecting to the mqtt broker\n", client_id.c_str()); 

//      if (client.connect(client_id.c_str(), mqtt_username, mqtt_password)) { 

      if (client.connect(client_id.c_str())) { 

          Serial.println("Mqtt broker connected"); 

          

      } else { 

          Serial.print("failed with state "); 

          Serial.print(client.state()); 

          delay(1000); 

      } 

 

  // Allow some time for initialization

  delay(500);

  }

} 

void loop() {

  uint8_t result1;   // Variable to store the result of Modbus operations

  uint16_t data1[2]; // Array to store the data read from the Modbus slave

  uint8_t result2;   // Variable to store the result of Modbus operations

  uint16_t data2[2]; // Array to store the data read from the Modbus slave

  uint8_t result3;   // Variable to store the result of Modbus operations

  uint16_t data3[2]; // Array to store the data read from the Modbus slave

 

  // Read 2 holding registers for node1 starting at address 0x0000

  // This function sends a Modbus request to the slave to read the registers

//  result1 = node1.readHoldingRegisters(0x0000, 2);

  result1 = node1.readHoldingRegisters(0x0000, 2);

 

  // If the read is successful, process the data

  if (result1 == node1.ku8MBSuccess) {

    // Get the response data from the response buffer

    data1[0] = node1.getResponseBuffer(0x00); // Humidity

    data1[1] = node1.getResponseBuffer(0x01); // Temperature

 

    // Calculate actual humidity and temperature values

    humidity1 = data1[0] / 10.0;      // Humidity is scaled by 10

    temperature1 = data1[1] / 10.0;   // Temperature is scaled by 10

 

    // Print the values to the Serial Monitor

    Serial.print("Humidity1: ");

    Serial.print(humidity1);

    Serial.println(" %RH");

 

    Serial.print("Temperature1: ");

    Serial.print(temperature1);

    Serial.println(" °C");

    Serial.println();

  } else {

    // Print an error message if the read fails

    Serial.print("Modbus read failed: ");

    Serial.println(result1, HEX); // Print the error code in hexadecimal format

    Serial.println();

  }

  delay(200);

  // Read 2 holding registers for node2 starting at address 0x0000

  // This function sends a Modbus request to the slave to read the registers

  result2 = node2.readHoldingRegisters(0x0000, 2);

 

  // If the read is successful, process the data

  if (result2 == node2.ku8MBSuccess) {

    // Get the response data from the response buffer

    data2[0] = node2.getResponseBuffer(0x00); // Humidity

    data2[1] = node2.getResponseBuffer(0x01); // Temperature

 

    // Calculate actual humidity and temperature values

    humidity2 = data2[0] / 10.0;      // Humidity is scaled by 10

    temperature2 = data2[1] / 10.0;   // Temperature is scaled by 10

 

    // Print the values to the Serial Monitor

    Serial.print("Humidity2: ");

    Serial.print(humidity2);

    Serial.println(" %RH");

 

    Serial.print("Temperature2: ");

    Serial.print(temperature2);

    Serial.println(" °C");

    Serial.println();

  } else {

    // Print an error message if the read fails

    Serial.print("Modbus read failed: ");

    Serial.println(result2, HEX); // Print the error code in hexadecimal format

    Serial.println();

  }

  delay(200);

  // Read 2 holding registers for node3 starting at address 0x0000

  // This function sends a Modbus request to the slave to read the registers

  result3 = node3.readHoldingRegisters(0x0000, 2);

 

  // If the read is successful, process the data

  if (result3 == node3.ku8MBSuccess) {

    // Get the response data from the response buffer

    data3[0] = node3.getResponseBuffer(0x00); // Humidity

    data3[1] = node3.getResponseBuffer(0x01); // Temperature

 

    // Calculate actual humidity and temperature values

    humidity3 = data3[0] / 10.0;      // Humidity is scaled by 10

    temperature3 = data3[1] / 10.0;   // Temperature is scaled by 10

 

    // Print the values to the Serial Monitor

    Serial.print("Humidity3: ");

    Serial.print(humidity3);

    Serial.println(" %RH");

 

    Serial.print("Temperature3: ");

    Serial.print(temperature3);

    Serial.println(" °C");

    Serial.println();

  } else {

    // Print an error message if the read fails

    Serial.print("Modbus read failed: ");

    Serial.println(result3, HEX); // Print the error code in hexadecimal format

    Serial.println();

  }

  client.loop();

  //client.publish(topic, temperatureTest ); //publish temp 

  sprintf(tempChar1,"%.2f", temperature1);

  Serial.print("tempChar1 = ");

  Serial.println(tempChar1);

  client.publish(topic1, tempChar1); //publish temp

  sprintf(humidChar1,"%.2f",humidity1);

  Serial.print("humidChar1 = ");

  Serial.println(humidChar1);

  client.publish(topic2, humidChar1); 

  sprintf(tempChar2,"%.2f", temperature2);

  Serial.print("tempChar2 = ");

  Serial.println(tempChar2);

  client.publish(topic3, tempChar2); //publish temp

  sprintf(humidChar2,"%.2f",humidity2);

  Serial.print("humidChar2 = ");

  Serial.println(humidChar2);

  client.publish(topic4, humidChar2); 

  sprintf(tempChar3,"%.2f", temperature3);

  Serial.print("tempChar3 = ");

  Serial.println(tempChar3);

  client.publish(topic5, tempChar3); //publish temp

  sprintf(humidChar3,"%.2f",humidity3);

  Serial.print("humidChar3 = ");

  Serial.println(humidChar3);

  client.publish(topic6, humidChar3); 

  // Wait for 2 seconds before the next read

  delay(2000);

}

RS485 Modbus to Raspberry Pi Pico 2W

 

A while ago I went to order a wind vane and Anemometer online and didn't pay attention and ended up receiving RS485 units rather than the 0-10VDC units I wanted....grin

This gave me the incentive to learn how to connect RS485 devices to ESP8266's, ESP32's and in this case a new Raspberry Pi Pico 2W that had just arrived.

Here is the TTL > RS485 board I am using:

The wind vane and Anemometer are already outside so I ordered a couple of Temperature & Humidity sensors that you see here to continue to experiment with the RS485 protocol. On the breadboard you can see the Pico 2W on the left and then side by side is the TTL > RS485 board and a RFID-RC522 board that I've been playing with on the Arduino Uno shown at the top of the picture.

I wasn't able to connect a RS485 device to a ESP8266 since, as I understand it, the main UART is used for the serial USB communication and the second UART is transmit only? So in the case of the wind vane and Anemometer I used a couple of ESP32's. Normally you can connect multiple RS485 devices on the same bus as long as you set unique addresses on each, however I haven't done that yet, so I connected each device to it's own ESP32. 

Given the low cost of the Pico 2W from  pishop.ca I was able to use the same software from the Arduino Modbus sketch and just change the Tx & Rx pin assignments.

The next step will be to add wireless & mqtt code to the Pico 2W so that it can transmit the temperature and humidity values to my mosquitto broker to be read by Node-Red on my Raspberry Pi

Thanks for reading!

Here is the code:

/* 

 *  TempHumidRS485a.ino

 *  Robin Greig

 *  2025.02.15

 *  

 *  Reads the Temp & Humidity of RS485 device and prints it to Serial Monitor

 *  

 *  Based on the ModbusMaster example below

*/

#include <ModbusMaster.h>       //https://github.com/4-20ma/ModbusMaster

#include <SoftwareSerial.h>

 

// Create a SoftwareSerial object to communicate with the MAX485 module

SoftwareSerial mySerial(1, 0); // RX, TX

 

// Create a ModbusMaster object

ModbusMaster node;

 

void setup() {

  // Initialize serial communication for debugging

  Serial.begin(115200);

  // Initialize SoftwareSerial for Modbus communication

  mySerial.begin(9600);

 

  // Initialize Modbus communication with the Modbus slave ID 1

  node.begin(1, mySerial);

 

  // Allow some time for initialization

  delay(1000);

}

 

void loop() {

  uint8_t result;   // Variable to store the result of Modbus operations

  uint16_t data[2]; // Array to store the data read from the Modbus slave

 

  // Read 2 holding registers starting at address 0x0000

  // This function sends a Modbus request to the slave to read the registers

  result = node.readHoldingRegisters(0x0000, 2);

 

  // If the read is successful, process the data

  if (result == node.ku8MBSuccess) {

    // Get the response data from the response buffer

    data[0] = node.getResponseBuffer(0x00); // Humidity

    data[1] = node.getResponseBuffer(0x01); // Temperature

 

    // Calculate actual humidity and temperature values

    float humidity = data[0] / 10.0;      // Humidity is scaled by 10

    float temperature = data[1] / 10.0;   // Temperature is scaled by 10

 

    // Print the values to the Serial Monitor

    Serial.print("Humidity: ");

    Serial.print(humidity);

    Serial.println(" %RH");

 

    Serial.print("Temperature: ");

    Serial.print(temperature);

    Serial.println(" °C");

    Serial.println();

  } else {

    // Print an error message if the read fails

    Serial.print("Modbus read failed: ");

    Serial.println(result, HEX); // Print the error code in hexadecimal format

  }

 

  // Wait for 2 seconds before the next read

  delay(5000);

}

RFID on Arduino

 

 I've been wanting to get develop a low security wooden lock box that I can use for a project. I've had these RFID-RC522 units for quite awhile and it was time to get back playing with them.

Rui & Sara Santos of Random Nerd Tutorials have a great tutorial on how to hook this up to an Arduino Uno as shown or ESP8266 or even ESP32 (both with WiFi). They also have a tutorial for using this RFID reader as an attendance checker.

I picked these up off from Phillip Fry Electronics Canada however they seem to be offline since Canada Post went on strike last fall and you can also get them off ebay. Inexpensive devices and the kits usually come with a card and keychain dongle. 

I've got a red LED inbetween the wires that I've hooked to a GPIO on the Uno and if the card ID is accepted, the LED lights. I could use that output with a FET to power a solenoid to unlock the door of my lockbox. 

Thanks for reading,

Robin

08 Feb 2025