Hi,
I'm beginning with PD so please bear with me
I'm trying to translate an existing application to PD, and having difficulties with a certain part.

In general, the application applies a filter when the input level is above a certain threshold. When it goes below the threshold, it waits for some time and stops applying the filter.

So there are three possible states: Normal, Wait, Stop. Here's a short pseudo-code to describe the state change logic:

if (level >= threshold) {
    state = Normal
}
else if (state == Normal) {
    TimerBegin()
    state = Wait
}
else if (state == Wait) {
    if (TimerElapsed() > waitTime) {
        state = Stop
    }
}

Afterwards, the state is used to determine whether to activate a filter:

if (state != Stop) {
    ApplyFilter()
}

What is the correct approach to implement this in PD? I understand that I need to use

Thanks!

Hi kshahar,

I came upon a similar problem when I wanted to be really efficient with switching off subpatches and fading them at the same time.

I've attached an abstraction that I use fairly regularly that will switch on immediately and switch off after a set time. In the second outlet I also output a ramp message for a line (or line~) object to fade up/down any audio in the same amount of time.

Hopefully it helps for your situation.

Cheers,
Joe

Edit: fixed bugs mentioned below

http://www.pdpatchrepo.info/hurleur/delswitch.zip

That's a good one. If you connect the second inlet of the abstraction to the second inlet of the [del $2], then it function even better when changing the number explicitly.
Thanks for sharing.

Hi Joe,

Thanks! it works perfectly for my needs.

I only had to add a "change" object for the input value, otherwise the delay restarts whenever the input changes (in my case, all the time).

Shahar

No worries, thanks for pointing that out, yep the second inlet was indeed meant to be connected to the delay.

That is actually an older version and a colleague wanted the inlets to change the settings dynamically. However, I find using inlets is not necessarily
the easiest interface and so made a version that allows you to send a control list in the format:

[valueToMoveTo rampTime delayTime ( e.g. [1 1000 1000 ( (It's the same format that [vline~] accepts)

Also added the ability to delay the ramp message, if you don't specify a value in the input list it'll default to the arguments of the abstraction.

http://www.pdpatchrepo.info/hurleur/delswitch+.zip

Hey kshahar,

Sorry yeah I grabbed an older version and didn't check for bugs. You definitely need a change in there

Glad it helped!