Category: interactive media art

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Raspberry-Pi FX pedal

Running in Pure Data

(update) Tried this with guitarist John Drew today (2/26/2012). We ran the guitar directly into the iMic (switched to microphone, not line) and the output of iMic into an amplifier. The R-Pi was plugged into to wifi router with an Ethernet cable, so we could use touchOsc to control the delay parameters. It sounded great.

We talked about the possibility of making this into a ‘product’. One idea would be to ditch the Osc controls and build a simple hardware interface – some encoders, switches, and LED’s. You could map everything in PD and download new patches using an ethernet cable or a usb wifi connection – or even some kind of serial/usb link.

Yesterday I programmed a simple variable delay effect in pd to run on Raspberry-Pi. Control was using touchOSC as described in previous posts. I ran the effect in mono at 32k sampling rate – and it sounded great. Also its using the Griffin iMic for sound.

Here’s the command line to set the sample rate and number of channels:

pd-extended -r 32000 -nogui -channels 1 delay-effect-osc.pd

 

Local files:

 

 

 

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Parsing Tweets into spoken language

notes

I’ve revised the php program that streams Tweets and sends them to Max, to remove hyperlinks, RT indicators, user mentions, and ascii art. Now it works better with text-to-speech.

things that could be done in a future project:

  • figure out which #hashtags are integral to content, and which are just tagged onto the end of a tweet
  • remove extraneous hyperlinks which don’t get parsed by the API
  • translate symbols like > into “great than” or “better than”
  • translate (or at least flag) foreign languages – this could be aided by geocoding data
  • translate slang acronyms like OMG, LOL
  • natural language parsing (see Stanford open source program) for content and grammatical analysis
  • replace hyperlinks/picture-links with a ‘title’ from the actual target
  • natural language equivalents of things like: RT @zooloo:
things to try
  • Running the output of text-to-speech through musical analysis tools, to detect pitch and rhythm
  • Chaining: Use the content of one tweet to direct a search for the next one. For example say you search for cats and get: “my cat is turning purple” – then you would search for ‘purple’ and get: “I’ve never eaten a purple cow” – then you would search for “cow” and so forth
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Twitter streaming API

from https://dev.twitter.com/docs/streaming-apis

This diagram shows the process of handling a stream, using a data store as an intermediary.

The JSON response breaks out various components of the tweet like hashtags and URL’s but it doesn’t provide a clean version of the text – which for example could be converted to speech.

Here’s a sample response which shows all the fields:

{
	"created_at": "Sat Feb 23 01:30:55 +0000 2013",
	"id": 305127564538691584,
	"id_str": "305127564538691584",
	"text": "Window Seat #photo #cats http:\/\/t.co\/sf0fHWEX2S",
	"source": "\u003ca href=\"http:\/\/www.echofon.com\/\" rel=\"nofollow\"\u003eEchofon\u003c\/a\u003e",
	"truncated": false,
	"in_reply_to_status_id": null,
	"in_reply_to_status_id_str": null,
	"in_reply_to_user_id": null,
	"in_reply_to_user_id_str": null,
	"in_reply_to_screen_name": null,
	"user": {
		"id": 19079184,
		"id_str": "19079184",
		"name": "theRobot Vegetable",
		"screen_name": "roveg",
		"location": "",
		"url": "http:\/\/south-fork.org\/",
		"description": "choose art, not life",
		"protected": false,
		"followers_count": 975,
		"friends_count": 454,
		"listed_count": 109,
		"created_at": "Fri Jan 16 18:38:11 +0000 2009",
		"favourites_count": 1018,
		"utc_offset": -39600,
		"time_zone": "International Date Line West",
		"geo_enabled": false,
		"verified": false,
		"statuses_count": 10888,
		"lang": "en",
		"contributors_enabled": false,
		"is_translator": false,
		"profile_background_color": "1A1B1F",
		"profile_background_image_url": "http:\/\/a0.twimg.com\/profile_background_images\/6824826\/BlogisattvasEtc.gif",
		"profile_background_image_url_https": "https:\/\/si0.twimg.com\/profile_background_images\/6824826\/BlogisattvasEtc.gif",
		"profile_background_tile": true,
		"profile_image_url": "http:\/\/a0.twimg.com\/profile_images\/266371487\/1roveggreen_normal.gif",
		"profile_image_url_https": "https:\/\/si0.twimg.com\/profile_images\/266371487\/1roveggreen_normal.gif",
		"profile_link_color": "2FC2EF",
		"profile_sidebar_border_color": "181A1E",
		"profile_sidebar_fill_color": "252429",
		"profile_text_color": "666666",
		"profile_use_background_image": false,
		"default_profile": false,
		"default_profile_image": false,
		"following": null,
		"follow_request_sent": null,
		"notifications": null
	},
	"geo": null,
	"coordinates": null,
	"place": null,
	"contributors": null,
	"retweet_count": 0,
	"entities": {
		"hashtags": [{
			"text": "photo",
			"indices": [12, 18]
		}, {
			"text": "cats",
			"indices": [19, 24]
		}],
		"urls": [{
			"url": "http:\/\/t.co\/sf0fHWEX2S",
			"expanded_url": "http:\/\/middle-fork.org\/?p=186",
			"display_url": "middle-fork.org\/?p=186",
			"indices": [25, 47]
		}],
		"user_mentions": []
	},
	"favorited": false,
	"retweeted": false,
	"possibly_sensitive": false,
	"filter_level": "medium"
}

 

 

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Parsing Tweets

A method using regexp and php. Actually what this does is parse Tweets using regexp to reformat the text as html with links. A tutorial here:

http://saturnboy.com/2010/02/parsing-twitter-with-regexp/

This is a php library that breaks out hashtags, usernames, etc., but doesn’t really provide a way to isolate the remaining stuff. I have put it in tkzic/API –  there is an example php program provided.

https://github.com/mzsanford/twitter-text-php

hashtags – using regular expressions

http://stackoverflow.com/questions/11551065/parsing-tweets-to-extract-hashtags-in-r

twitter-text-rb : ruby gem which parses out usernames and hashtags

https://github.com/twitter/twitter-text-rb

 

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data recording

Thoughts on a streaming API project model with Max.

I’ve been trying to come up with generalized methods to handle the class of Max projects which read a stream of data from the Web, and use it to trigger events, for example, sound and graphics.

OSC is generally a good way to get data into Max from Web API’s. One issue with data streams, is that they do not always provide a constant flow. In some cases, this is what makes them musical. The rhythm of the flow becomes the rhythm of the music.

But in some cases we are vexed by too little flow or too much.

When the flow is too sparse, and the project requires a constant flow – the stream can be fattened up by using a [metro] object to output the current stream value at a higher frequency.

When the flow is too fast – you can use [speedlim] for numbers – but not for text data like tweets about cats, which seem to stream in like a flood. One solution is to use a data-recorder, like our modified CNMAT list recorder in the Irish Train project.

You would need separate access to the record and play ‘heads’ – so for example you could record in real time, but start playing back at a slower rate (while the recording continues). This is essentially a form of stream buffering. The data recorder approach would also allow you to use various algorithms to ‘thin’ the data – for example, to keep up with the real time rate, but by using less of the data.

[update] got this working with the modified CNMAT data recorder patch. It allows separate control of recording and playback, simultaneously.

patch is in tkzic/max teaching examples/ data-recorder-tester.maxpat

 

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Osc in php

The Osc code from the stock market music project https://reactivemusic.net/?p=12029 is not really doing Osc.

But… it works well going from php->max. In the other direction its using a kluge of nc and an alarm clock shell program – to receive messages from Max in UDP, but its really kind of horrible – so I’m going to look again for an OSC library in php.

update 2/2013 This is hard to believe, but I haven’t yet found a real OSC libraries for php. Apparently php is so uncool, that nobody wants to write for it anymore. Anyway, the code above, works unidirectionally, so its of some use for existing php code.

Local files are max-php-osc-tester.maxpat and max-osc-play.php in tkzic/api

Analysis that might help with parsing:

from Captain Caveman

http://forum.cockos.com/showthread.php?t=99076

 

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Twitter streaming php decoder breaks out individual tweets

This code was adapted (i.e. stolen verbatim) from a stackoverflow post by drew010

http://stackoverflow.com/questions/10337984/using-the-curl-output

Here’s the code. It solves a huge problem for the class of projects which need to grab a large amount of tweets in real time to either save in a database, or trigger some action.

My version of the code is in tkzic/api/twitterStream1.php

<?php

$USERNAME = 'youruser';
$PASSWORD = 'yourpass';
$QUERY    = 'nike';

/**
 * Called every time a chunk of data is read, this will be a json encoded message
 * 
 * @param resource $handle The curl handle
 * @param string   $data   The data chunk (json message)
 */
function writeCallback($handle, $data)
{
    /*
    echo "-----------------------------------------------------------\n";
    echo $data;
    echo "-----------------------------------------------------------\n";
    */

    $json = json_decode($data);
    if (isset($json->user) && isset($json->text)) {
        echo "@{$json->user->screen_name}: {$json->text}\n\n";
    }

    return strlen($data);
}

$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, 'https://stream.twitter.com/1/statuses/filter.json?track=' . urlencode($QUERY));
curl_setopt($ch, CURLOPT_USERPWD, "$USERNAME:$PASSWORD");
curl_setopt($ch, CURLOPT_WRITEFUNCTION, 'writeCallback');
curl_setopt($ch, CURLOPT_TIMEOUT, 20); // disconnect after 20 seconds for testing
curl_setopt($ch, CURLOPT_VERBOSE, 1);  // debugging
curl_setopt($ch, CURLOPT_ENCODING,  'gzip, deflate'); // req'd to get gzip
curl_setopt($ch, CURLOPT_USERAGENT, 'tstreamer/1.0'); // req'd to get gzip

curl_exec($ch); // commence streaming

$info = curl_getinfo($ch);

var_dump($info);