You're not showing the rest of the patch which is where the actual problem occurs, but I guess you can threshold it and use [change]. So, something like this:

[comport]
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[> 100] <- this value is an example, don't know what you get when you're within your desired distance
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[change]
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[sel 1] <- this will trigger your sound

doesn't sudo apt-get install puredata work?
Also, if you download the latest Pd version, it includes an INSTALL.txt file which explains the whole procedure to compile from source. I have compiled Pd on a Pi many times without a problem.

How about using [ggee/shell] to get a list of devices on /media/pi? If you have only one USB stick plugged in, then ls /media/pi should return only that. Then you can use the returned name and search files there, like open /media/pi/usb_drive/file1.wav for example.
Though you probably won't be able to use [shell[ in Bela, as it's not vanilla.

Both abstraction here provide a resonant filter. These abstractions are a wrapper around Mike-Moser Booth's [filtercoeff.mmb~] and [biquad.mmb~] abstractions eliminating the use of [expr~].
Don't know if it's what you're looking for, but they are vanilla and can definitely run on a Bela.

Thanks, but there's no link...

Can you share the Arduino code?

the iemguts library inlcudes the [oreceive] object which can have its receive name set dynamically. You can also define the reception order in case you have more than one [oreceive]s with the same name.

In [pd~]'s help patch it writes pd~ start pd~-maypatchname.pd(
Did you miss the pd~ part attached to the name of the patch?

What about your package manager?

That's exactly what I was looking for, thanks!

Messing with ofelia's examples I'm trying to figure out how to send a string arriving via OSC in a Pd patch into ofelia's inlet and display that in its window.
The examples provided either have hard-coded strings or the stuff displayed are being created inside the Lua script.

[tabread4~] just reads an array, You feed it an index and it outputs the value at the given index. In more detail, [tabread4~] does a four point interpolation when receiving floats, because these values are in between indexes, since indexes are integers (you don't get an index 1.5). That's all. [phasor~] is multiplied by the size of the array, so it outputs a ramp from 0 to the size of the array, and that is an incrementing index for [tabread4~].

If you want to add randomness, you can modulate the frequency of [phasor~], or use another oscillator, possibly wihth FM or PM (phase modulation).

[tabread4~] is not ready made to playback audio. You need something to drive it, and most of the times that's [phasor~]. [phasor~] is a ramp going from 0 to 1 in the frequency specified either as an argument or through input in its left inlet. If you multiply its output by the number of elements of the array [tabread4~] is reading from, then you get whatever is stored in that array. In order to hear it at proper speed, you need to divide your sampling rate by the number of samples of your audio file (the number of elements of the array), and that will be the frequency of the [phasor~].

So, to answer your 2nd question, [phasor~] is not a sound signal, it's just a ramp which is used as a driving force. If you use another sound signal to drive your playback with [tabread4~], you're going to get a playback with variable speed that will go forward and backward.

Hi,
If you're using the default exaples from GitHub, and you're using [serial_print], then you're using a 9600 baud rate. You can change the baud rate to 57600 or 115200 to get better results.
Bear in mind though that using Serial.print() is significantly slower than Serial.write(), cause the later sends raw bytes, while the former translates everything to its ASCII values. So, if you want to sent the value 100 with Serial.write(), the Arduino will just send one byte, whereas with Serial.print() it will send three bytes, the values 49, 48, 48 (ASCII for 1, 0, 0).

Can't you just edit the crontab and open the patch from there with the appropriate flags?
Type crontab -e which will prompt you to choose an editor (nano will be the default, better use that one). Scroll to the end of the file and type this:
@reboot sleep 20 ; pd -nogui -audiodev 3 -open /path/to/patch.pd &
This will force the Pi to launch Pd without the GUI, choose the third audio device (first is Pi's default audio hardware, second is default audio plugin, third should be any sound card connected as hardware), and open your patch. The ampersand (&) tells the Pi to run Pd in the background so you can still do things with it in the terminal.

Once you type this, hit Ctl+O to save the file and hit return as you'll be asked to save the changed you made. I'm pretty sure this will work.

Thanks for making this, it's an amazing library!

What does Arduino's power supply have to do with the current the relay will let through or not? A relay is an electronic switch which receives power (usually of high voltage) and has three more pins, one for 5V, one for ground, and one to control the actual switch. These three pins are the ones you connect to the Arduino, and Arduino's 5V pin is more than enough to power the digital part of the relay. The high voltage the relay will let through or not has nothing to do with Arduino's power supply and digital control.

Don't know what you're trying to do, and can't really understand the conversation, but thought I post these couple of things I know about relays.

Why would you damage the boards? I don't think relays have changed in the way they work, since 2011. What is this that you find and don't trust?

Try this:

[phasor~ 1]
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[threshold~ 0.1 10 0.1 10]
                         |
                        [o]

The bottom object is a bang

My suggestion was for when you boot up the Pi only. If you're opening Pd patches through Python, you should replace the command that launches Pd with a command that launches your Python script and open Pd from there. In that case you don't need to wait 30 seconds every time, only at boot time for the Python script to launch.
But why do you have to quit Pd and restart it? Can't you just close the patch and open a new one? There are internal messages in Pd that can do that.