How to Stop an Arduino Program?

When learning how to use an Arduino, it is important to understand how to conclude any programs that you run.

This will help prevent errors and protect your hardware from damage.

There are a few different ways to stop running Arduino software, and the most appropriate method will depend on your goals for the project.

However, in general, the easiest way to stop this program type is to use the reset button on the board. This will cause the program to start from the beginning, which can be useful for debugging purposes. Additionally, you can use the bootloader to erase the contents of the board or to upload a new sketch.

Finally, if you are using an Arduino IDE, you can click on the “Stop” button in the toolbar to reset the board and stop any running code. By understanding how to cancel the working Arduino program, you will be able to more effectively use this powerful tool for your projects.

Methods of Finishing the Arduino Program:

1) Turn off the power – in such a way you will unplug the software safely

The software should be carefully disconnected from a power source at any time. When unplugged, it will cease operating its current program and almost all of its memory. The program will reset any non-volatile data stored in the EEPROM and program memory [1]. When you restore the power outage, the program automatically executes its most recent sketch from its setup().

However, any program variables will still be stored in the volatile random access memory (RAM).

When the power is restored, a program can be reset:

• It executes the setup() function again;
• All information has vanished, and all variables have been erased;
• All peripherals will have to be configured again;

When the power is shut off, variables and data may be safely stored using the EEPROM. This protocol type does not lose memory when the power is disconnected. The EEPROM is a type of non-volatile memory that does not get wiped when a program is reset or loses power. It can be compared to a tiny SD card for the software.

2) Ways to reset the programs – use the button or code

There is a soft/hard reset button on the side of the hardware that can cease and reboot the program to the default settings. When it is pressed, the reboot option causes the microcontroller to shut down.

If your device has a problem with the WiFi chip, for example, it will not be reset until you remove power from the board. Peripherals like microSD cards and USB ports will still be in their last state if your gadget has a problem with the WiFi chip, and they should be initialized again.

If the button is depressed for 10 milliseconds, the microprocessor will be reset. Any data that isn’t stored in the EEPROM or program memory will be lost when the microcontroller is restarted.

The reset button will:

• Stop the current sketch from running;
• Restart the sketch from setup();
• Erase any data stored in variables in RAM;
• Not erase any data stored in EEPROM;

To use the reset button, press and release it quickly. The LED on the software will turn off, indicating that it is no longer running the current sketch. Pressing and holding the reset button for longer than a few seconds will cause the program to restart its bootloader, which may be used to upload a new sketch.

3) Cancel the software loop from running by causing the pause

If you want to stop a loop from running, you can use the break keyword. The break keyword will cause the program to exit the current loop and continue running the rest of the sketch.

If your software gets trapped in an infinite loop that you need to stop executing, there is a command available in a sketch that can be utilized to free oneself from the loop.

The software may quit a loop with the break statement. When writing a sketch that contains an infinite loop, putting the break keyword at the end of it instructs the program to leave. This does not apply to the loop function, which can be terminated using return.

For example, if you have a for loop that is supposed to run 10 times, but you want to stop it after 5 iterations, you can use the break keyword.

4) Trap the program running in a loop to cancel it from executing the wrong code lines

One of the most common ways to stop the program from executing code is by trapping it in a loop. This can be done using a number of different techniques, such as writing conditional statements, using timers, or triggering interrupts.

For example, if you want to control when your sketch runs loops based on time or incoming sensor data, you can create conditional checks for these conditions and add them to your code.

5) Consider using the Sleep Mode option to cancel the program

Entering Sleep Mode puts the program in a low-power state that can be maintained for weeks or months at a time without harming the device. It is possible to choose how you want the program to be awakened before shutting it down. The software is generally set to wake up by timer or via an external interrupt. Depending on which board you’re using, you can select from a variety of sleep modes.

The program can enter Sleep Mode by using the sleep() method. This instructs the software to cease all operations, except for timer-based tasks, until an interrupt occurs.

Once the program is in Sleep Mode, you can wake it up by triggering an external interrupt or a built-in timer. Conditional statements and other commands allow you to create a variety of programs that use Sleep Mode to control when your device executes code.

6) Execute an external relay to cut the power off to the program

If you need to stop an Arduino from running a specific piece of code without resetting or halting it, you can apply an external relay option to cut the power to the device. This will allow you to easily shut down your program while preserving its current state so that you can restart the program later.

The simplest way to cut power to the software is by using an external relay. An external relay contains two terminals: one for controlling whether or not there is power, and one that connects directly to either VCC or GND on your board depending on how it is wired. By connecting these two terminals together with a switch, you can control when your program is powered on and off.

7) Designate a kill switch in your sketch

If you want to be able to quickly stop your software from running a sketch, you can designate a kill switch in your code. This is typically done by connecting a physical button or switch to the program that, when activated, will cause the device to execute a specific command.

You can design a kill switch for your program by adding a physical button or switch to your circuit. When this button or switch is activated, it should trigger a certain function in your code that will stop the execution of your sketch. This could be as simple as calling the exit() function or writing a conditional statement that halts the loop.

Check our articles to improve your knowledge in Arduino development:

• How to Use a Microphone with Arduino?
• How to Use an Active Buzzer with Arduino?
• How to Make an Arduino Ohm Meter?

Comparing Methods to Stop an Arduino Program

When working with Arduino boards, it’s crucial to know how to stop or terminate a running program. Different methods can be employed to halt the execution of an Arduino program. This table compares various indicators that showcase the different approaches to stop an Arduino program.

Method	Implementation	Complexity	Use Cases	Pros	Cons
1. Using Infinite Loop	while(1) {}	Simple	–	Easy to implement Useful for short-duration programs	Not ideal for long-running programs May cause watchdog reset
2. Utilizing ‘return;’ Statement	return;	Simple	–	Stops the program gracefully Allows cleanup before termination	Requires functions to return void Not suitable for multi-threaded applications
3. Using ‘exit(0);’ Function	exit(0);	Simple	–	Terminates the program immediately Helpful for handling fatal errors	Doesn’t call destructors for global objects May leave hardware in an undefined state
4. Using Watchdog Timer	Watchdog Timer	Moderate	–	Automatic reset after a timeout Useful for recovering from system crashes	Requires additional configuration May lead to unexpected restarts
5. Handling External Triggers	Interrupts	Complex	–	Allows stopping the program based on events Useful for real-time systems	Requires understanding of interrupt handling Potential conflicts with other interrupts

Explanation:

• Method: The name of the method to stop the Arduino program.
• Implementation: The code snippet or function used to implement the method.
• Complexity: Represents the complexity level of each method, categorized as Simple, Moderate, or Complex.
• Use Cases: Describes any specific scenarios or use cases where the method is particularly suitable.
• Pros: Lists the advantages or benefits of using the respective method.
• Cons: Enumerates the limitations or drawbacks associated with each method.

The table provides a comparison of five different methods to stop an Arduino program. The methods range from simple techniques like using an infinite loop (while(1) {}) to more complex ones involving interrupts. Each method has its own set of advantages and disadvantages, making them suitable for specific scenarios. Programmers can choose the most appropriate method based on the complexity of their program, the need for graceful termination, and the potential trade-offs in terms of system stability and ease of implementation.

FAQ

How to use the button to start/stop the loop?

The Arduino platform is a popular choice for developers who are interested in experimenting with microcontroller programming and hardware. One of the most common questions that new users have is how to stop an Arduino program once it has been started.

There are typically two ways to do this [3]:

1. The easiest option is to use one of the physical buttons on your Arduino board, such as the reset button or the power button. Simply press this button at any time during your code to stop the loop and halt any further execution;
2. Alternatively, you can also use software commands to stop your program from running. This involves using functions like while(!digitalRead(7)) {} or while(1) {} to create infinite loops that will continue running until they are manually stopped;

To stop an Arduino program using a physical button, simply press and hold the reset button or power button on your board for a few seconds. This will cause the microcontroller to reset itself and stop any further execution of your code. If you are using an Arduino Uno, you can also use the onboard power LED as a physical indicator that your code has been halted. Simply turn off the power to the board and the LED will turn off, indicating that the program has been stopped.

How to avoid using the delay function in Arduino sketches?

In most situations, millis() is a superior, non-blocking alternative to time(). Timing issues are all too common in computer programming. The Arduino function delay() delays the program for a set number of milliseconds given as a parameter [4].

How do you stop an Arduino script?

There are a number of ways to stop an Arduino script from running.

The most common method is to press the reset button on the Arduino board, which will cause the current program to stop running and restart from the beginning.

Another way to stop an Arduino program is to disconnect the power supply to the board. This will cause all programs stored on the board to be erased, so it is not recommended unless you are sure you do not need any of the programs on the board anymore.

If you want to keep your programs on the board but prevent them from running, you can disable the autorun feature in the Arduino IDE. This will prevent any programs from automatically running when you connect power to the board or upload a new program.

You can also use the kill command in the Arduino IDE to terminate a running program. This is useful if you need to stop a program stuck in an infinite loop or, otherwise, it is not responding to input.

Can I just unplug my Arduino?

Yes, you can unplug your Arduino without damaging it. The ATmega chip on the Arduino has built-in safeguards that protect it from damage if no external power is applied [5].

How do I stop an Arduino program without unplugging it?

There are a few ways to stop an Arduino program without unplugging it.

One way is to use the Serial Monitor in the Arduino IDE. You can open the Serial Monitor by clicking the icon on the toolbar or selecting Tools > Serial Monitor from the menu bar.

With the Serial Monitor open, you can send a “newline” character (ASCII code 10) to your Arduino, which will cause your program to exit.

Another way to stop an Arduino program is to press the reset button on the board. This will cause your program to restart from the beginning.

Finally, you can disconnect the power supply to your Arduino. This will cause your program to stop completely and may damage your hardware if not done carefully [6].

How can I stop an Arduino program during its execution?

To stop an Arduino program while it is running, you can incorporate specific conditions in your code that trigger an exit from the main loop. For example, you can use a button press or a specific input to break out of the loop and stop the program’s execution.

Is there a way to pause the Arduino program temporarily?

Yes, you can implement a pause functionality in your Arduino program by utilizing the `delay()` function. However, keep in mind that using `delay()` can lead to unresponsive behavior, so it’s recommended to use other techniques like the “Millis” method to achieve a non-blocking delay.

Can I terminate an Arduino program using software commands?

Yes, you can stop an Arduino program by including an “exit” condition in your code. By checking for this condition in the main loop, you can terminate the program’s execution gracefully.

How do I implement an emergency stop feature in my Arduino project?

To create an emergency stop feature, you can connect a physical button or a sensor to the Arduino board. When activated, this input can trigger a function that interrupts the main loop, effectively stopping the program’s execution.

What is the purpose of using the “return” statement to stop an Arduino program?

Using the “return” statement in your Arduino code can be a straightforward way to exit the program from within a function. By executing a “return” statement at the appropriate location, you can halt the program’s execution and return to the calling code.

How can I disable certain functionalities of my Arduino project temporarily?

You can implement a feature flag system in your Arduino program, which allows you to enable or disable specific functionalities. By checking the status of these flags at various points in your code, you can effectively turn off or bypass certain parts of your project temporarily.

Can I utilize interrupts to stop an Arduino program?

Yes, you can use interrupts in your Arduino project to respond to external events and stop the program’s execution. When an interrupt is triggered, the Arduino jumps to the designated interrupt service routine, allowing you to perform necessary actions before returning to the main loop.

How do I halt the execution of a time-sensitive Arduino program?

For time-sensitive applications, it’s crucial to ensure precise timing. To stop the program, you can use a “flag” variable that indicates when the program should stop processing. By monitoring this variable in the main loop, you can exit the program gracefully when the specified time period has elapsed.

What precautions should I take before stopping an Arduino program abruptly?

Before abruptly stopping an Arduino program, make sure to disable any critical components, such as motors or actuators, to prevent unexpected behavior. Additionally, properly release any resources, such as memory, to avoid potential issues during the program termination.

How can I resume an Arduino program after stopping it?

To resume an Arduino program after stopping, you need to reset the board or power cycle it. When you restart the Arduino, it will initiate the program from the beginning, allowing you to continue its execution.

Useful Video: Arduino Programming Tutorials || “Soft Emergency Stop” using an Externally Triggered Interrupt

References:

1. https://chipwired.com/stop-arduino-running/
2. https://robotsbench.com/how-to-stop-an-arduino-program/
3. https://www.instructables.com/Start-Stop-Button-Switch-With-Arduino/
4. https://dzone.com/articles/arduino-using-millis-instead-of-delay
5. https://arduino.stackexchange.com/questions/4769/can-i-simply-unplug-the-arduino-usb-if-serial-communication-is-active
6. https://chipwired.com/stop-arduino-running/