2

Background

I am trying to learn how to use the rpio library (https://github.com/jperkin/node-rpio) in my nodejs application.

What do I want to do

So far I have been able to test the blink led example form the documentation, and I was trying to do the push button test ("Poll a button switch for events" as is it called at the documentation). I had copied the content of the example and tried to execute it both when a page loads, to execute it on the server-side through a post request, and tried also in simply executing it when the server starts. Here is the code:

rpio.open(15, rpio.INPUT, rpio.PULL_UP);

function pollcb(pin)
{
        /*
         * Wait for a small period of time to avoid rapid changes which
         * can't all be caught with the 1ms polling frequency.  If the
         * pin is no longer down after the wait then ignore it.
         */
        rpio.msleep(20);

        if (rpio.read(pin))
                return;

        console.log('Button pressed on pin P%d', pin);
}

rpio.poll(15, pollcb, rpio.POLL_DOWN);

I am using the circuit schematic as shown at the image below: source:https://github.com/raspberrypilearning/physical-computing-guide/blob/master/pull_up_down.md

The difference is that I dont have the switch, but I guess that just using wires to simulate the pessing of a button will do it

The problem

It is not working at all... Everytime when I call the function, my ssh command line gets stuck for 5-10 seconds and then my connection to the raspberry pi is reset, not allowing me to connect to the raspberry again; and then I have to unplug the raspberry to restart it! It is like the whole board collapses when I try to do this approach, which is also concerning me about the fact that I have to shut down my raspberry not in a safe way, what can consequently corrupt my sd card.

edit: It looks like that whenever I try to execute the rpio.poll function, it breaks the application and the board.

I appreciate any possible help about this issue.. Thank you!

6
  • Does RPIO actually run on the Pi you are using? Do you need to be running it with root access? Have you asked the author? – joan Jul 10 '19 at 19:58
  • Hello, are you using the 3.3v from the Pi for your circuit or is is a separate supply? Have you double checked the resistor values you're using? – Roger Jones Jul 11 '19 at 9:25
  • @joan yes it does, it is saying in the documentation that it supports the b+ model. – Roger Peixoto Jul 11 '19 at 10:25
  • @RogerJones hey Roger, I am using the 3.3V from the Pi. Yes, I have double checked for sure! – Roger Peixoto Jul 11 '19 at 10:26
  • Just re-read your question and noticed that running the command crashes the Pi, not pressing the button. My mistake: I was worried you had the wrong resistors and were essentially shorting the 3.3v supply to ground. Anything of note in the system log when you restart? – Roger Jones Jul 11 '19 at 11:20
1

Unfortunately I was not able to put it to work using the rpio.poll function

However, I managed to listen to the input pin by using a setInterval() method:

function status(){
    rpio.open(15, rpio.INPUT, rpio.PULL_UP);
    setInterval(function(){
        var status = rpio.read(15)
        console.log(status)
    },1000)
}

I did try to listen every second, which was enough for the purpose in which I wanted to work, but if anyone try with a smaller interval, it might work as well.

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