Tag: arduino

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ep-4yy13 DSP – week 13

“I think its just the biggest conceptual art project uninentional or otherwise that anyone ever made. it puts Christo and those other guys to shame. Its planetary”

Roman Mars “Episode 97 – Numbers Stations” from 99% Invisible

Radio

  • Measuring the invisible
  • What is the difference between sound waves and radio waves?
  • What is an antenna?
  • Wave propagation is frequency dependent
  • Sunspots and magnetic fields http://spaceweather.com
  • Extreme frequencies, negative frequencies?

examples

Internet radio streams and recordings

Frequencies and modes
  • Macbook trackpad: Noise 5 mHz. (try holding radio near screen too)
  • Macbook AC adapter: Noise 600-1400 kHz. (~1000)
  • AC adapters, LED’s, Utility poles: 3.2 Khz
  • Arduino transmitter: AM 1330 kHz.
  • Laser light at 650nM
  • Wireless micorophone (Orange-brown): Wide FM 614.150 MHz. (R band)
  • Cordless phone: Narrow FM 926 mHz.
  • Cell phone: Digitally encrypted trunking FM 836 mHz.
  • Wifi: Digitally encoded PCM 2.4 gHz.
  • FM broadcast band: Wide FM 89.7 mHz (Raspberry Pi example 98.1 Mhz)
  • TV audio 600 mhz/660 mhz FMW
  • The sun http://www.ips.gov.au/Solar/3/4

Topics not covered

(due to snow and stuff)

Visualization

 

  • d3
  • processing
  • jitter
  • hardware control

Statistics

Miscellaneous

Assignment

Please send me a copies of your earlier compositions. Have a prototype ready to demonstrate or talk about for the next class.

 

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How to change Twitter trigger with Xively to use Zapier

notes

This method was used to fix the tweetcurl series of Max patches and anything else which uses Tom Igoe’s method of sending tweets from Arduino via cosm.

http://www.tigoe.com/pcomp/code/arduinowiring/1135/ (old method)

The automatic twitter trigger used in the “internet sensors” project via cosm, stopped working when cosm migrated to xively.com. But it works correctly from a device (or Max) to xively. So you don’t need to change anything except the xively trigger associated with the feed.

The fix is to go into your xively feed (legacy feed) delete the existing trigger and set up a new trigger using zapier – using the instructions in this tutorial.

https://xively.com/dev/tutorials/zapier/

Notes:

  • You will need to sign up for a free zapier account
  • the text value of the tweet for zapier is called “body trigger datastream value value”
  • limited to 10 tweets per hour
  • when you select Twitter as an action in zapier, it will attempt to log you in to do the oauth authentication. If you are already logged into Twitter – make sure its the correct account.

If you really want to send Tweets from Max, check out the Twitter client that uses ruby: https://reactivemusic.net/?p=7013

 

 

 

 

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how to open, read, and write from a serial port in C (linux)

With applications for Raspberry Pi

notes

by hobbytronics.com

http://www.hobbytronics.co.uk/raspberry-pi-serial-port

C – programming example:

http://stackoverflow.com/questions/6947413/how-to-open-read-and-write-from-serial-port-in-c

An R-Pi thread about connecting Arduino to R-Pi. R-Pi does TTL (3.3 v level and Arduino is rs-232 5v) so you need a level converter for them to communicate.

http://www.raspberrypi.org/phpBB3/viewtopic.php?f=31&t=23873

Another similar example, connecting Arduino and R-pi via USB

http://www.raspberrypi.org/phpBB3/viewtopic.php?f=32&t=28801

The WiringPi library for serial io:

https://projects.drogon.net/raspberry-pi/wiringpi/serial-library/

 

 

 

 

 

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RTTY with Arduino

Transmitting on 434.650 MHz.

Successfully ran the configuration described in this article

By Anthony Stirk at UKHAS

http://ukhas.org.uk/guides:linkingarduinotontx2

Have only tried 50 baud – but the beacon ran for over an hour without errors. The receiving   setup was done on a Windows 7 computer:

  • Funcube (software defined radio)
  • FCHID (software to tune the Funcube)
  • Spectraview (demodulate signal from Funcube to SSB)
  • FLDigi (decode RTTY using custom setup)

The bandwidth of the RTTY signal was close to 900 instead of something more reasonable like 50. This can be adjusted by trying various resistor values in the voltage divider circuit.

Next steps include building antennas and increasing the baud rate.

 

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using a WiFi router as a closed local network

I set up a WiFi router today at school, with no internet connection to use for ssh logins to Raspberry Pi and OSC experiments with Arduino. It has the same SSID as my home router so it will be interesting to see what happens when I go from one place to the other. 

Update: Actually this works great. Have been using it for any situation that requires OSC.