Hi all, I'm struggling a bit on audio latency in pd (windows), so I wanted to have a clearer picture.
Apparently other applications seems to perform quite well (Reaktor), but in pd I'm experiencing serious problems.
I did a simple test, the result is here:

• pd .042.5 extended
• pd patch: 7.stuff/tools/latency.pd, measurement quite precise (Miller says ~1.5 ms)
• audio board: Cakewalk Sonar VS-100 (roland), USB 2.
• ASIO4ALL driver (portaudio)
• line out (1) cable jack connected to line in 1 (mic)
• windows 7 (64 bits)

Pretty instructive, at least for myself. I put a Scope~ object to visually see the output pulse fed back into input of the audio board:
the "sharp" pulse is the one generated by the patch, the "blurred" one that follows is the one fed back into the audio board.
The distance between the two is the "latency" of the system.

In summary, these are the major results I found:

• lowest true (measured) usable latency ~ 30 ms, corresponding to "delay (msec)" set to ~ 8 ms
• lowest true (unusable) latency ~ 20 ms, audio "destructed" "delay (msec)" set to ~ 3 ms
• Original HW driver is totally unuseful, only ASIO4ALL seems working ok (why? anyone has an idea?)
• I probably used very bad cables (see the bad pulse shape following the one created by the latency patch)
• changing the ASIO4ALL buffer size didn't change anything in terms of latency (why?)

Note: the only way I was able to lower down the "delay (msec)" values to few msec was using ASIO4ALL driver.

I'd like to hear your experience (I read about Domien playing "delayed") and if anyone was able to succeed to lower
the latency in win to unnoticeable values (~10 ms or even less).

Alberto

Saw your TED video, so maybe you've already solved this problem.

In my limited work with getting arduino and pd to play nice, I've found that things like pduino and firmata work great but can be restrictive. I had to multiplex inputs on my arduino, which doesn't play nice with something like firmata that automatically reads all the pin values.

It might be better to have each arduino on it's own [comport], and differentiate the arduinos that way. Dump pin values over each comport and keep reading it.

Here's the thread explaining what I did:
http://puredata.hurleur.com/sujet-5832-reading-multiplexed-input-streams-arduino

I'm a fan of your work.

Hello,
Although there seems to be endless information on the internet on using an Arduino board with Pure-Data, I haven't found any info that will make it work for me... So, I'm seeking for some help.

So I'm trying to use my Arduino board to read galvanic skin response. I've got that nearly working. Where I'm having trouble is getting the data into PD in the correct format.
Here is the code I have for my Arduino:
// Arduino Code
int sensorPin = A0;
int sensorValue = 0;

void setup() {
Serial.begin(9600);
}

void loop() {
float conductance = getVoltage(sensorPin);
Serial.println(conductance);
Serial.write(conductance);
delay(1000);
}

float getVoltage(int pin){
return (analogRead(pin));
}
// End Arduino Code.

I'm using the comport object in PD. And I am receiving Data which is analogous to what I'm doing on the board. But I can't understand exactly what it is reading. Here is the link to my PD patch: http://www.sendspace.com/file/n81jlj
So Firstly, the Numbers keep jumping around, and secondly I'm not sure what those numbers are. What I'd like them to be is the individual analog inputs of my Arduino. But they clearly aren't as they all change when I play around with my arduino board. Also they seem to range between 0 and 255, whereas my Arduino reads the data as 10bits...

Any sugestions!?
Thank you,
Niko.

hey,

I don't know but I wonder if maybe there isn't a more general problem going on right now (though it seems simple and wierd so I dont get it)
I am also having trouble loading abstractions even though I have done it quite a lot before, in particular (I posted this problem a few days ago but am posting in response to your problem in hopes that it might be a more global problem - though my abstractions, other than the ones mentioned below, load so I dont understand)

specifically, was the problem with the path not being recognised?

anyway -
Hello everyone,

This is a strange problem because I have loaded libraries and things with the 'Paths' dialog under the file menu before and had no problems.

I am trying to get Chris McCormick's s-abstractions to load. The folder is in the same folder as my other libraries and it is listed in both the "paths" and "startup" areas. It wasn't before but I added it.

I am running windows 7 64 bit. Another oddity that I noticed is that in my Program Files (x86) which is where the 64 bit programs live, I have pd installed and the folder is simply called pd. However in the Program Files folder (missing the x86, where the non-64 bit programs live) I have a folder called "Pd-0.42.5-extended"

I wonder if that couldn't be the problem. The s-abstractions folder is included in both though...

Hopefully somebody has some idea about this...

((anyway sorry to post twice but I hoped maybe there was some common problem there))

hey hey!

probably my problems with pd's audio latency are easy to explain and eliminate, but by now i didn't make it by myself.

basically i am trying to create a looping-module for some simple live overdubbing. i already supposed that i have to factor in the latency for precise timing, but the presetted 50ms doesn't bring correct results. so i measured the latency with this latency.pd patch, using jack to create the feedback, it shows me a latency of about 24.6ms. is this latency constant? and what does the 50ms-preset mean?

and by the way, what are the first steps to optimize (minimize) the latency?

i am using ubuntu studio, pd-extended and right now the built-in sound card of my ibm think pad t41.

thank you!

I am trying to find out if and how to create an arduino fio/xbee based wireless network of multiple fio/xbee's? 4 to be exact.

I am currently building a wireless system consisting of 2 "hand units", a wireless mouth interface and a base station xbee interfacing with pure data. www.beatjazz.blogspot.com. i already have the first fio/xbee communicating with the base station and pure data using pduino and all is perfect. this weekend i pick up the other 2 arduinos and fio's. all 3 arduinos need to connect with the pure data at the same time.

the instrument i am building is a wind midi controller except that instead of it being one horn like instrument, allthe left hand keys are in a wireless unit attached to the left hand and same goes for the right hand. the mouthpiece is worn like a headset microphone and is a pressure transducer for breath and a FSR for lip pressure. they must all work together as if one instrument. most of the coding has been done, andnow is time to split that code to the multiple wireless nodes.

it would seem that since all the xbee's have their own id's that that would translate over to the arduinos they are connected with and the whole network should come into the computer thru one serial port, which should solve that problem. I am wondering; how i might interface the 3 arduinos to pure data/pduino? theoretically, shouldnt i be able to name instances of the [arduino] object, say [arduino left], [arduino right], and [arduino mouth] so that each fio has its own instance? if so, how do i recognize the individual fio's and make use of their individual id's if that is the case at all?

Thank you in advance for any insight anyone might share.

Onyx

Hi to all, this is my first post in this forum.
I'm trying to use PD's patches inside my setup, and now I'm struggling with the MIDI latency that PD creates.

First of all, I'm a drummer and I use a drumpad(DrumKat) to trigger samples on my laptop, so for me the latency is a 1st class problem.
I have two setups: one with Ubuntu 10.04(Kernel 2.6.33-29-realtime) + jack, and the other with OSX leopard + jackosx. The first one is the more tested.

I want to know the latency that PD creates between notein-noteout process.
To do this, I simply connected my drumpad to PD's midiin, PD's midiout to PD's midiin, and opened my patch(attached to this post).

If the patch is right, there is a link between jack's latency and PD's MIDI latency.
If I set jack's framebuffer to 256, I have 11.6 msec of audio latency and 5.8 ms of PD's MIDI latency.
If I set jack's framebuffer to 128, I have 5.8 msec of audio latency and 2.9 ms of PD's MIDI latency.

Is this correct? Is there a way to reduce MIDI latency without changing the audio latency of jack?

Thank you and sorry for my english.

Nicola

http://www.pdpatchrepo.info/hurleur/pd-midi_latency_test.pd

Dear Pd'ers… I'm fairly new to Pd and have been using it during my 'Audio Production' degree at SAE college in London. I'm here to ask for help on my final degree project, which aims to control objects within Pd by way of proximity sensors connected to Arduino.

I have had moderate success, first using a Sharp GPD12 IR sensor connected to an analog port on an Arduino Diecimila, then a Devantech SRF02 connected via I2C to Arduino. I have managed to get Pure Data reading the sensor values using the Pure Data example included in SimpleMessageSystem (http://www.arduino.cc/playground/uploads/Code/SimpleMessageSystem.zip)... and only altering the number of the comport the Arduino appears on.

On the Arduino end, I have added the SimpleMessageSystem library, and am using the following sketch to run one or both of the sensors depending on whether or not I omit the SRF02 or GPD12 parts of the code.

// top //

#include <Wire.h>
#include <Servo.h>
#include <SimpleMessageSystem.h>

int sensorPin = 0;
int sensorValue = 0;

Servo servo1;

#define sensorAddress 0x70
#define readInches 0x50
#define readCentimeters 0x51
#define readMicroseconds 0x52
#define resultRegister 0x02

void setup()
{
Wire.begin();
Serial.begin(9600);
}

void sendCommand (int address, int command) {
Wire.beginTransmission(address);
Wire.send(0x00);
Wire.send(command);
Wire.endTransmission();
}

void setRegister(int address, int thisRegister) {
Wire.beginTransmission(address);
Wire.send(thisRegister);
Wire.endTransmission();
}
int readData(int address, int numBytes) {

int result = 0;

Wire.requestFrom(address, numBytes);
while (Wire.available() < 2 );{
}

result = Wire.receive() * 256;
result = result + Wire.receive();
return result;
}

void loop()
{
// SRF02 READING //
sendCommand(sensorAddress, readInches);
delay(70);
setRegister(sensorAddress, resultRegister);
int sensorReading = readData(sensorAddress, 2);
Serial.println(sensorReading);

delay (200);

// GPD12 READING //
sensorValue = analogRead(sensorPin);
int range = (6787 / sensorValue);
Serial.println(range);

delay(200);
}

// bottom //

Pure data is picking up the sensor's output as a decimal number, through the serial port, correctly, and showing this as a number in the SPECIAL CHARACTER section of the Pd patch, which I can then use to control various Pd parameters, like a slider for example.

If printing both sensor readings to the serial, the Pd patch will pick up the two sensor values alternately, but there seems no way of differentiating the two sensors within Pd, as they both come through the serial. I have tried prepending the serial print at the Arduino stage with a tag such as "IR" or "UL" for each sensor, but this simply ends up in nothing coming through in Pd.

Using one sensor gives the ability to control parameters with a fairly narrow detection range, but for the final version I would like to incorporate 4 or 5 sensors in order that I can cover nearly a full 360 degree range.

After a bit of research I have gone and bought 4 x Maxsonar EZ0's. They've got a wider range than the Devantech sensors, and can operate via I2C, serial or PWM. A number of people online seem to mention the improved stability when operating via PWM, so I thought this could be kinda useful.

I am going to London Hackspace tomorrow to get help with wiring up the sensors to my Arduino Diecimila, but for now, my main problem seems to be how to achieve greater communication between Pure Data and the sensors. It's all very good and well being able to take the decimal readout from an analog input to give one set of values in Pd, but I would like to know how to either to read (and trigger) each sensor discretely via PWM, or to somehow differentiate between each sensor's analog output, so that I can have the different sensors controlling different objects within Pd.

As well as SimpleMessageSystem, I looked at using the Pduino object. But to be honest, it is either not working properly (I have noticed reported issues with bugginess), or I am being stupid, as it has totally boggled my brain. In theory though, it seems like it should be able to do what I want, ie. send and receive commands between Arduino and Pd.

****************************************
So&#8230;. my questions for anyone out there with a knowledge of using Arduino + multiple sensors (preferably Maxsonar EZ's) with Pd are:

What is most appropriate for my project?

• Simple Message System or Pduino?
• analog or PWM?
  And how do I get proper communication between the two platforms so I can discern discrete values from each sensor?

I'd really like to get a discussion going with this as (a) it would really help me in my degree (which ends in about 4 weeks!!!) and (b) I really want to share what I am doing, especially as the discussions on Arduino/Pd communication on the various forums seem a little patchy (at least for noobs like me). I also hope to continue my research in the future, sharing any findings I make with the community&#8230;
****************************************

PS. In the sharing spirit, please check out the Radio Tuner patch I've just posted over on the patch section of this forum - it's my first successful attempt at Pd... I hope you enjoy

Hello,
I've been using a Mac Mini running pd-extended and two arduino boards attached to it to control some electric motors of an installation. I use Pduino and the StandardFirmata uploaded into arduino and I had no problems until I decided to do a file transfer from my MacBook into this Mac Mini using Bluetooth. I opened the Setup Bluetooth Device, I chose to open a connection to my computer and did the file transfer.

Unfortunatelly, when I opened the patch I've been working for several months, one of the two arduino boards was not working. The comand

[open 2<
|
[arduino]

started to cause an error message saying the port I was using was no longer of my arduino but the tty.Bluetooth port related to my MacBook. I turned off the Bluetooth Devices of both computer but the tty port related to that bluetooth transfer is still in "the place of" my arduino usb tty port.

Then I tryed all the possibilities: [open 0<, [open 1< and [open 4< to try to find the right tty port. The [open 3< is already in use by the other arduino board which fortunatelly is still working. When i tryed [open 5< I received the message that I could only use more than four ports on .

Do anyone no how to manage these tty ports? Can I erase the tty port related to the bluetooth transfer? Will that cause my arduino tty port to come back to the list in which pure data can access?

I'm a bit scared because the installation will be exposed in two weeks!

Thank you very much for your attention.
Skrako.

@Maelstorm said:

If you're on OSX, jack can be used as an insert plug-in so you can avoid the separate tracks, but you still get the latency.

which you can, depending on your host, eliminate by setting the track delay for the track with the plugin. So if the buffer is 512 sample/11.82 ms then set the delay to that and it should be spot on.

I've had the whole Jack graph latency explained to me numerous times by Stephane Letz and it still doesn't go in.....Heres what he told me...

> > Its the Pd > JAck > Ableton latency. (Ableton has otoh 3 different
> > ways of manually setting latency compensation - I'm just not very
> > clear on where to start with regards to input from JAck)
> >>>>
>
> This is NO latency introduced in a Pd > JAck > Ableton kind of
> chain; the JACK server activate each client in turn (that is Pd *then*
> Ableton in this case) in the *same* given audio cycle.
>
> Remember : the JACK server is able to "sort" (in some way) the graph
> of all connected clients to activate each client audio callback at the
> right place during the audio cycle. For example:
>
> 1) in a sequential kind of graph like IN ==> A ==> B ==> C ==> OUT,
> JACK server will activate A (which would typically consume new audio
> buffers available in machine audio IN drivers) then activate B (which
> would typically consume "output" just produced by A) , then activate
> C , then produce the machine OUT audio buffers.
>
> 2) in a graph will parallel sub-graph like : IN ==> A ==> B ==> C
> ==> OUT and IN ==> D ==> B ==> C ==> OUT (that is both A and D are
> connected to input and send to , then JACK server is able to
> activate A and D at the same time (since the both only depends of IN)
> and a multi-core machine will typically run A and D at the same time
> on 2 different cores. Then when A *and* D are finished, B can be
> activated... and so on.
>
> The input/output latency of a usual CoreAudio application running
> is: driver input latency + driver input latency offset + 2
> application buffer-size + driver output latency + driver output
> latency offset.
>

this next part is the important bit i think...

> For a graph of JACK clients: driver input latency + driver input
> latency offset + 2 JACK Server buffer-size + ( one extra buffer-
> size ) + driver output latency + driver output latency offset.
>
> (Note : there is an additional one extra buffer-size latency on OSX,
> since the JACK server is running in the so called "asynchronous" mode
> [there is also a "synchronous" mode without this one extra buffer-size
> available, but it is less reliable on OSX and we choose to use the
> "asynchronous" mode by default.])
>
> Stephane
>