user-1: On an Arduino you can have several different interrupt types, two of them being RISING and FALLING. Looking past that RISING is from LOW to HIGH, and FALLING is the opposite, what are the benefits of using one or the other?
To clarify; why would you use a RISING interrupt or a FALLING interrupt?

user10591: Suppose you have a pushbutton that connects Arduino pin to the ground. The pin is also pulled up  to VCC (may be internally in Atmega chip, or through external resistor). Now, when the switch is open, Arduino sees HIGH, and when you press the button it sees LOW. If you would like to perform an action when the button is pressed, you would use FALLING interrupt. If you would like to know when the button is released, you would use RISING. There are no general benefits of using one over another.

user11729: Imagine that you have the circuit below:

simulate this circuit – Schematic created using CircuitLab
Let's say that you wanted to catch the user pressing the button. The input signal will go from high to low, which is a falling edge. So you would use a FALLING interrupt to catch this event. Easy, right?
Now let's say you wanted to catch a user releasing the button instead. This time the inverse is true, so you want to use a RISING interrupt.
You should note that since these interrupts are edge triggered, the simple circuit below would not be ideal. Without any debouncing, there may be several edges to trigger from, resulting in repeated interrupts. Also, given the analogue nature of the design, we can't be sure that the rise / fall times will be fast enough to trigger the edge interrupt. We can get around this by adding a 100nF capacitor across the switch and following by a Schmitt trigger (which I can't find a symbol for in the circuit editor!).
So to answer your question, you use the interrupt that is correct for the event you are trying to catch. The Arduino MCU implements both edges for completeness and flexibility in your design, so if this interrupt was coming from an external IC you have no control over the design of, you can easily match the interrupt to its behaviour without having to add in an inverter.

-1: <p>On an Arduino you can have several different interrupt types, two of them being RISING and FALLING. Looking past that RISING is from LOW to HIGH, and FALLING is the opposite, what are the benefits of using one or the other?</p>

<p>To clarify; why would you use a RISING interrupt or a FALLING interrupt?</p>
 10591: <p>Suppose you have a pushbutton that connects Arduino pin to the ground. The pin is also pulled up  to VCC (may be internally in Atmega chip, or through external resistor). Now, when the switch is open, Arduino sees HIGH, and when you press the button it sees LOW. If you would like to perform an action when the button is pressed, you would use FALLING interrupt. If you would like to know when the button is released, you would use RISING. There are no general benefits of using one over another.</p>
 11729: <p>Imagine that you have the circuit below:</p>



<p><img src="https://i.stack.imgur.com/RFd8S.png" alt="schematic"></p>



<p><sup><a href="/plugins/schematics?image=http%3a%2f%2fi.stack.imgur.com%2fRFd8S.png">simulate this circuit</a> &ndash; Schematic created using <a href="https://www.circuitlab.com/" rel="noreferrer">CircuitLab</a></sup></p>

<p>Let's say that you wanted to catch the user pressing the button. The input signal will go from high to low, which is a falling edge. So you would use a FALLING interrupt to catch this event. Easy, right?</p>

<p>Now let's say you wanted to catch a user releasing the button instead. This time the inverse is true, so you want to use a RISING interrupt.</p>

<p>You should note that since these interrupts are edge triggered, the simple circuit below would not be ideal. Without any debouncing, there may be several edges to trigger from, resulting in repeated interrupts. Also, given the analogue nature of the design, we can't be sure that the rise / fall times will be fast enough to trigger the edge interrupt. We can get around this by adding a 100nF capacitor across the switch and following by a Schmitt trigger (which I can't find a symbol for in the circuit editor!).</p>

<p>So to answer your question, you use the interrupt that is correct for the event you are trying to catch. The Arduino MCU implements both edges for completeness and flexibility in your design, so if this interrupt was coming from an external IC you have no control over the design of, you can easily match the interrupt to its behaviour without having to add in an inverter.</p>
