read pin & blocking

[guizmo51]

Hi, thanks for your very useful library ! I try to listen changes on a specif pin (on input only). It works if I use "gpio.read()" but the script is waiting for action after.. How to solve it ?

My goal is to listen chane but the eventlistener is not working for me :(

thanks for your help !

[julienvincent]

Hi, please can you include some code to show what you are trying to do.

[guizmo51]

Hi, Here is what I have : https://gist.github.com/guizmo51/84f0881d1a5634c58ae22f86772dadb8 (blocking after the console.log() )

Intially I used the "change" listener but it doesn't work.

[julienvincent]

Are you sure it's not just hanging. Can you continue code execution? It is expected to hang after a pin setup as from that point on it is listening for changes.

[guizmo51]

Sorry for the missunderstood. Yes it's probably hanging, but hanging about what ? I just want to listen changes on this pin.. do you have working exemple ?

[julienvincent]

after a setup, the module will be start polling for interrupts signalling a change. When a pin change happens, the module will emit a change event you can hook in and listen to these events by adding a call back function like so:

gpio.on('change', (channel, value) => {
   // channel -> pin that changed
   // value -> the new state of the pin. 0/1
})

[guizmo51]

Well, I already try that but no change was détected (instead of the getter). I will try again tonight. Thanks !

[julienvincent]

The reason it was not detecting a change is because you are not specifying the edge. If you look at the documentation you will see that you need to specify an edge when listening for changes.

[julienvincent]

In future please make sure to read documentation before opening an issue.

[guizmo51]

Hi Julien, I understand to read the documentation before and this is why I did. During the day I hadn't my Pi. Toninght I just try again the same snippet and now it works. Thanks.