In the world of electronics and IoT projects, controlling relays is a common task. However, ensuring reliable and consistent relay control between devices can sometimes be challenging. In this article, we will discuss a simple approach to handle data loss during transmission and maintain the same relay status between the transmitter and receiver devices.
Controlling a relay wirelessly can be a convenient way to operate electrical devices or machines remotely. With the help of a transmitter and receiver, it is possible to control the relay’s on/off state without physically being near it. In this article, we will discuss the code required to send and receive relay status using a transmitter and receiver setup.
An Introduction to Transmitter and Receiver Communication
Components and Setup
In order to establish communication between a transmitter and receiver, certain components are required. For the receiver device, the following components are needed. These components can be found in the description below where links are provided for proper connection. Additionally, a wiring diagram for the receiver device is also available for reference to ensure accurate connections and prevent any potential damage to the hardware.
The relay module is connected to the receiver device, allowing for control through the use of a button on the transmitter. By pressing the button on the transmitter, the relay on the receiver device can be turned on or off, enabling seamless communication between the two devices. This functionality ensures that both the transmitter and receiver have the same relay status, while also handling any potential data loss that may occur during transmission.
Constant Status Updates
To maintain synchronization between the devices and ensure reliable communication, the receiver constantly sends relay status updates back to the transmitter. These updates occur at regular intervals of 3 seconds. This continuous transmission of relay status is indicated by the LED connected to the transmitter, which will continuously blink to signify the reception of relay status from the receiver device.
It is important to ensure that the components used in the project are compatible with each other. For the Lora module, which operates at 3.3 volts, a 3.3 volt spin of the Arduino is used for powering it. Additionally, a voltage divider is attached to the RX pin of the Lora module to convert the 5 volt signal to 3.3 volts, ensuring compatibility with the module.
Simplifying the Setup
Next, to simplify the setup process, I have already connected all the components to both devices using a breadboard. This provides a convenient and solder-free way to establish connections, making the entire process more straightforward. By using the breadboard, you can easily modify or adjust the connections without the need for permanent soldering.
Coding the Transmitter
Now let’s move to the coding section. Here, I have two files. The first one is “Laura_button.ino”, which will be used to write the code for the transmitter. The second file is “Laura_relay.ino”, and it will be used to write the code for the receiver device.
Including the Software Serial Library
To start with the transmitter code, you will need to include the Software Serial Library. This library enables serial communication between the Arduino and the LoRa module. The pin 2 on the Arduino will act as the RX pin, and the pin 3 will act as the TX pin.
Setting Up the LoRa Communication
Next, you will need to set up some important settings for the LoRa communication. The first one is the frequency band of the LoRa module. This module operates on various frequency bands, so you can choose the one that best suits your needs. Make sure the frequency will be the same on both devices.
After that, you will need to define the network ID for the LoRa module. In this case, I have set it to 7. Make sure both devices share the same network ID for communication. Now, let’s define the address for this device. In our case, the address of this device is one. It’s important to note that the address of both devices must be unique and different from each other.
Setting up the Receiver Device
Finally, it’s time to specify the address of the receiver device that will be connected to the relay. This step is crucial to ensure that the correct device receives the transmitted data.
Defining the Pins
In addition to setting up the address, we also need to define the pins for the push button and the LED. These pins will be responsible for the input and output functions of the receiver device.
Creating a Boolean Variable
To keep track of the current status of the relay, we will create a Boolean variable. This variable will help us determine whether the relay is currently on or off.
Copying the Code to the Receiver
Now that the first section of the code is complete, you can simply copy and paste it onto the receiver side. However, there are a few changes that need to be made. The address of this device should be set to 2, and the address of the other device should be set to 1.
Additionally, since the receiver device only has a relay connected, there is no need for the LED, pin, and button pin variables. In this case, the relay pin variable will be defined instead.
Continuing the Coding Process in the Transmitter
Now, let’s move back to the transmitter to continue with the coding process. In the setup function, the first step is to initialize the serial communication with the computer. This will help us debug the code if needed.
Next, we will start the serial communication with the Laura module for transmitting the data. It’s important to ensure that the baud rate for both devices remains the same to establish a successful communication link.
Then, we need to set the button pin to input mode and enable the pull-up resistor to sense the button press. Additionally, we will set the pin mode of the LED pin to output to control the LED’s behavior.
Configuring Communication Parameters
To ensure proper communication between the devices, we need to send specific commands to the Laura module. These commands will configure the frequency band to 433 megahertz, set the network ID to 7, and assign the address of this device to 1. By doing this, we establish a clear communication channel.
Configuring the Laura Module
Remember, before using the Laura module, it is necessary to configure it properly. Follow these steps to set up the module for communication.
Setting up the Receiver Code
1. Copy the code within the setup function of the Laura module.
2. Paste the copied code into the setup function of the receiver code.
3. Remove the code related to the push button and LED.
4. Set the pin mode of the relay pin to Output.
Continuing with the Transmitter Code
Now, let’s go back to the transmitter code and proceed with the loop function.
Detecting the Button Press
To detect the button press, an if condition will be used in the loop function. This condition checks the status of the button pin. When the button pin is low, it indicates that the button has been pressed.
Sending Commands to the Receiver
Once the button is pressed, a command will be sent to the receiver device to control the relay. The relay status variable will be updated, toggling between true and false.
Creating the Command
Based on the relay status variable, a command will be created. If the relay status is true, the command variable will store “A1”, which will be used to turn on the relay. If the relay status is false, the command variable will store “0”, which will be used to turn off the relay.
Initiating Lora Communication
To transmit the command to the receiver device, Lora communication needs to be started. First, specify the address of the receiver device. Then, define the number of characters you want to send. Since our command consists of just two characters, set the character count accordingly.
By following these steps, you can successfully configure the Laura module for communication between the transmitter and receiver devices.
Controlling a Relay using Transmitter and Receiver
In this article, we will learn how to control a relay using a transmitter and receiver. This setup can be useful in various applications where you need to remotely control devices. We will go through the code step by step and explain the functionality of each section.
Setting Up the Transmitter
To start, we need to set the number of characters to two. This will determine the length of the command that will be sent to the receiver. The command variable will hold either a 0 or A1, depending on the relay status. Once the complete string is constructed, it will be sent to the receiver device. Additionally, the command variable will be displayed on the serial monitor for monitoring purposes. A delay of 500 milliseconds will also be added to handle button bounces. With these steps, the transmitter code is ready.
Implementing the Receiver Code
Moving on to the receiver code, we will focus on the loop function. Here, we will write the necessary code to receive the data sent from the transmitter. A while loop will continuously check for incoming data, and once new data becomes available, it will be read and stored in the data variable. This received data will then be printed on the serial monitor for analysis and debugging.
Controlling the Relay
Once the data is received, we need to control the relay based on the command specified in the received data. We will use an if condition to check if the incoming data contains the command “A1”. This command indicates that the transmitter has sent an instruction to turn on the relay. In this case, the relay will be turned on using the digital write function, and the relay status variable will be updated to 1 to indicate that the relay is now on.
Similarly, if the incoming data contains the command “A0”, the relay will be turned off.
By following these steps, you can successfully control a relay using a transmitter and receiver setup. This can be expanded upon and integrated into various projects that require remote control capabilities.
Ensuring Reliable and Consistent Relay Control
Before we dive into the code implementation, let’s go over the initial setup. The relay status variable is initially set to 0, indicating that the relay is currently off. To establish communication between the devices, the code needs to be uploaded to both the transmitter and receiver devices. This can be done by selecting the appropriate board and COM port from the tools menu in your IDE.
Handling Data Loss
One common problem that arises during relay control is data loss during transmission. Occasionally, the push button on the transmitter device may not work due to this data loss. As a result, the relay status variable may mismatch between the two devices, leading to unexpected outputs.
To handle this issue, we will utilize the receiver device to periodically send the current relay status to the transmitter. In turn, the transmitter will update its relay status based on the received data from the receiver. This approach ensures that both devices maintain the same relay status at all times.
Implementing the Code
To achieve reliable and consistent relay control, we will make use of the loop function on the receiver side. Within this function, we will write a sample code to execute a certain task at a specific interval. In our case, we will set the interval to 5 seconds.
Within the if condition for this interval, we will update the relay status variable on the receiver side. This updated status will then be transmitted to the transmitter, allowing it to maintain the same relay status. By regularly sending the relay status, we minimize the chances of data loss and ensure the consistency of relay control between the two devices.
Controlling a Relay Using a Transmitter and Receiver
Sending Relay Status
To send the relay status back to the transmitter, we can utilize the existing code for this purpose. Within the given condition, the code for sending the relay status can be written. By reusing the already developed code, we can ensure the efficient transmission of data from the receiver device to the transmitter.
Preparing the Receiver Device
On the receiver’s end, the device needs to be prepared to send the relay status to the transmitter. This involves implementing the necessary code on the receiver device. To achieve this, the code for receiving the relay status can be copied and pasted into the loop function of the transmitter device. However, some modifications are required.
Modifying the Transmitter Code
After pasting the code for receiving the relay status, certain changes need to be made. Initially, the relay pin should be replaced with the LED pin. This LED will blink whenever the transmitter receives the relay status from the receiver. Additionally, after the while loop, the LED should be turned off with a small delay of 50 milliseconds. These changes ensure that the transmitter properly displays the relay status received from the receiver.
Uploading the Code
Once the code has been modified, it is ready to be uploaded to the transmitter device. After the successful upload, the second code should be uploaded to the receiver device. These steps are essential for establishing the communication between the transmitter and receiver and ensuring the proper functioning of the relay.
Controlling the Relay
With the setup complete, you can now control the relay by pressing the push button on the transmitter device. The LED on the transmitter will blink to indicate the relay status being received from the receiver. This wireless control offers convenience and flexibility, allowing you to operate the relay from a distance without the need for direct physical contact.
Transmitter and receiver communication is made possible through the use of various components and careful wiring. By utilizing a relay module and a button on the transmitter, seamless control of the relay on the receiver device is achieved. Constant relay status updates are sent from the receiver to the transmitter, providing synchronization between the devices and handling any data loss that may occur during transmission. Paying attention to voltage compatibility and ensuring accurate connections are crucial for successful communication and preventing damage to the hardware.
Controlling relays between devices can be a complex task, especially when data loss is involved. However, by implementing a simple approach of periodically sending the relay status from the receiver to the transmitter, we can maintain a reliable and consistent relay control system. This approach helps to avoid unexpected outputs and ensures that both devices are synchronized in their relay operations.
Implementing a transmitter and receiver setup enables remote control of a relay. By following the steps outlined in this article and modifying the code accordingly, you can easily send and receive relay status wirelessly. This opens up possibilities for various applications, providing a seamless and efficient solution for controlling electrical devices from a distance.