Project 1: hooking up the R820T SDR with the Raspberry Pi (Wont work)

In order to turn the R820T into an SDR (software defined radio) device, a number of programs need to be installed on the Raspberry Pi.

First of all, git needs to be installed on Pi. An easy install onto Debian can be done through terminal by typing in “$ apt-get install git”. If permission is denied, type “$ sudo apt-get install git” to initialize as superuser, which essentially overrides all permission.

Before jumping in, I wanted to learn what all these commands were, specifically “make”. I learned that make has a long history in linux. It is essentially a package compiler and installer. After downloading a repo, make must be used to build the app out. A great intro to make is here.

Also, before starting, its a good idea to update Raspbian with “sudo apt-get update” and after that, type: “sudo apt–get install cmake build–essential python–pip libusb–1.0–0–dev python–numpy git”

This will install the libusb repo, which to my understanding is what allows communication with the dongle.

After that, I followed adafruit’s installation commands for the stl-sdr library for interfacing with the dongle. The library they suggested to clone is:
In a fresh terminal window, type these commands exactly.
cd ~
git clone git://git.osmocom.org/rtl-sdr.git
cd rtl-sdr
mkdir build
cd build
cmake ../ -DINSTALL_UDEV_RULES=ON -DDETACH_KERNEL_DRIVER=ON
make
sudo make install
sudo ldconfig

After that is installed, it is important to copy the rtl-sdr.rules file to /etc/udev/rules.d
I did this by opening up a terminal window from the rtl-sdr folder and typing: “sudo cp -i rtl-sdr.rules /etc/udev/rules.d”. The cp command takes two inputs, the file you wish to copy, followed by the directory path you wish to paste it to.

Finally, to test the R820T usb dongle. In a fresh terminal window, type sudo rtl_test -t. Theoretically, this should open up a connection with the dongle and start spitting out a frequency or at least show some data. Unfortunately for me, this was not the case. Instead I recieved a nasty error. It successfuly found the device, but it gave me a “usb_claim_interface error -6” and the device fails to open.

A great conversation about this issue is found on a post to hamradioscience.com. The specific thread is here.

When using the R820T, people consistently reported having the same issue. Some people suggest using an externally powered usb port, because the dongle may draw to much energy from the Pi.

Alternatively, I tried installing a fork of the original library that is more up-to-date. Unfortunately, this didn’t solve anything. It seems to be a hardware problem.

TL;DR The R820T dongle wont work on the Raspberry Pi unless it is externally powered (i have yet to test that, so i cannot confirm). Instead, people suggest using the 2832u E4000 chip, which is, unfortunately, not as finely tunable as the R820T. Hopefully someone will find a fix for this.

Project 1: moving forward with RaspberryPi

In order to receive police radio signals and output the data to an Arduino, A few options were presented to me.

Originally i wanted to be mostly dependent on hardware, meaning that I would use a traditional radio setup with a tuner. Sparkfun’s Si4702 FM radio reciever board looked promising until I read the datasheet. The chip can’t tune to frequencies above 108MHz FM. Unfortunately Manhattan precincts all broadcast well above that frequency – mostly broadcasting above 400 MHz. 🙁

A few alternatives were brought to my attention.

1.) I could use a Raspberry Pi (which i have no previous experience with) and SDR usb dongle to pick up on specific frequencies, that could later be output to an Arduino via an audio jack that would oscillate between 0V and +5V.

2.) I could purchase a premade radio scanner and hack it to fit my project. Such scanners can be found on EBAY. A list of top of the line hobby radio scanners are here.

3.) A more advanced radio tuning chip is in the making that would likely give me the reception I need. the chip is capable of receiving between 50 MHz and 1000 MHz!! This range is astounding… but it looks like it is still in development. If and when it comes out, this chip could come in handy.

At the moment, I am using Raspberry Pi and SDR.
I am currently running Raspbian. I have purchased and am waiting for:

wireless mouse and keyboard
dvi to hdmi converter
SDR usb dongle and antenna
BNC female to MCX male dongle
mini haptic motors

Once I have received those I will:

setup the Raspberry Pi with the RTL2832U SDR usb dongle. For that I will need follow this Raspberry Pi forum post on setting it up through command line.

Utilize the documentation on how to use what is called demod.

If I can get past that I will move onto getting audio output from the Pi.

Beyond that, will be the next steps of the project.

set up communication with Arduino
make haptic components respond according to the audio
design the hoodie and integrate the electronic components

Project 1: next steps

In order to receive police radio information, parse it, and output a response to another device, like an Arduino and create the wearable, I will need to complete these two tutorials:

Adafruit’s raspberry pi SDR police radio scanner guide comes with a list of components needed to turn a raspbery pi’s computing power into a radio.
https://learn.adafruit.com/freq-show-raspberry-pi-rtl-sdr-scanner/overview

and

A nice instructables guide shows that it is possible for an Arduino to read radio frequency! It’s quite the hacky process because Arduino can only read between 0V and +5V, there are a few steps to transform the radio wave to fit. This combined with the raspbery Pi, and i should be able to hook up some vibration motors to place around the hoodie to create haptic feed back for the wearer.
http://www.instructables.com/id/Arduino-Audio-Input/step2/Prepare-audio-jack/

Project 1 initial steps

The project:

I will make a wearable device in collaboration with my previous suitemate and founder of K2O, James Halls Collins. The first version of the wearable will be an iteration of their “BADMAN” hoodie. Electronics will be integrated into the hoodie so that it will be able to pick up on police radio frequencies within the Brooklyn/Manhattan area.

The goal:
In response to recent events culminating from Ferguson, Missouri the wearable seeks to create greater balance between police and citizen – particularly providing wearers of the hoodie with the advantage of a live instrument for detecting police proximity. The hoodie will translate the radio waves into some sort of haptic or visual feedback mechanism embedded within the garment that will give the perception of proximity.

I have already received James approval to move ahead with the project.

next steps:

figure out a design for the hoodie based on the components I will be using.

Determine what technologies i need in order to interface with hertzian space.

A few items I have come across that i am considering/doing research on:

Software Defined Radio

conductive thread

Neo Pixel

Arduino Uno, Lillypad or Adafruit Gemma

EL Wire

fiber optic fabric

Studio Project One PDF presentation

Studio

Reading Response to Dunne & Raby

As I read both the readings I was thinking about what my project should be. Before I could figure out what the project was going to be I needed to pose some questions. This is the result of the new questions and understandings that I arrived at after the readings:

I was particularly interesting in the Dunne & Rabby reading about Hertzian space because they made me aware of a space that previously I had no idea existed beyond my phone’s recognition of wifi and a car radio’s ability to receive music signals from towers. There are so many terms and new vocabulary for describing Hetzian space and those who have found way to interact with and utilize it. Hertzian space is an area beyond normal human perception, which is why the vocabulary around it is so odd. It has to be very specific in order to describe this very particular area of the universe – the spectrum. A word has to be invented to designate something as existing because thats how humans communicate concepts, ideas, and things – especially things beyond which can be understood using our built in biological sensors. Senses such as taste, touch, sight, hearing, and smell can be used to share an experience with other humans because they have the same sensory abilities. For example, An apple is equally understood between two individuals from opposite sides of the globe as a fruit because it is sweet when eaten. it feels waxy to the touch and we can see that it grows on trees and that it has a stem. All of these features, which we can detect using our external sensory functions, of an apple make up how we, as humans define it to be an apple. But how do you understand something entirely that is beyond our natural human sensory perception? How do you describe such a thing? It is abstract if it has not been grounded in reality through our senses. Another language is required to describe realms beyond human perception: math. Mathematical equations can describe natural phenomenons that are beyond normal human perception. For instance Hertzian space is made up of the electromagnetic spectrum, which is understood in terms of frequency and is visualized as oscillating waves. However, this is still an abstraction of the original form and it is still removed from our senses. It is not truly representative.

How can we make Hertzian space into a place? How can we make Hertzian space more tangible? In what ways can we visualize Hertzian space? It is omnipresent, yet the only way we understand it to exist is the moment we lose connection to the internet and have to reconnect. Only in moments where we require access to the internet, but cannot get on, do we realize its existence, other wise we take it for granted that we can search wikipedia and surf google.

As James Hunter puts it, “we create ‘place’ only through continual acts of seizure.” That is, a space is something that doesn’t exist, is not defined, yet is everywhere and is only turned into place when something grabs your attention, pulling you away from your normal monotonous flow. Place is created where disruptions push an pull the normal current of time as perceived by a human. Hertzian space, at the moment, is disrupting people all the time when their internet goes out, but in a way that isn’t enjoyable, gainful, or fun. There were a few examples of people who were actively seizing hertzian space by searching for natural radio frequencies traveling through space and interacting with Earths ionosphere. What if there were some way to disrupt ones normal flow of activity by making them more aware of the dense radioscape they are surrounded by? How could the invisible become visible, tangible, and real to the human senses? These are questions I am beginning to ask as well as think about ways in which the questions can be materialized into a project.

Images related to Pallasmaa

Buildings inspired by nature, and not.

Examples of human center design and non human center design.

8 Spruce Street Downtown Manhattan. Designed by Frank Gehry.

Stata Center at MIT, Cambridge also designed by Frank Gehry.

Denver Art Museum in Denver, Co. Designed by Daniel Libeskind, also assistant architect of the Freedom Tower.

Guggenheim Museum, NY designed by Frank Lloyd Wright

Lideta Mercado, Ethiopia, designed by Xavier Vilalta

Studio Environments

Studio: Environments Reading Response

Thoughts on Mzerleau-Ponty

How are Merleau-Ponty’s ideas on perception helpful in understanding our surroundings?

What topics from the reading do you currently apply to your own work?

Merleau-Ponty believes that we are innately connected with body and mind and that one cannot exist without the other. The only way we can perceive reality is with our senses and the only way that we can interpret reality is with our mind. Communication with those two are absolutely important to understanding our world. The only way we understand the world that we live in is through the five senses we have developed as a species. Using those senses in combination with our mind, we can understand our surroundings as whole pieces. To give an example, It is impossible to understand what a lemon is without tasting its acidic, sour juice, touching its leathery skin, smelling its puckering aroma, and hearing the sound of your mouth sucking the juice out of a slice of the fruit. If you isolate the individual senses, then it becomes difficult to understand an object in it entirety. You could break it down into its individual molecular properties and describe what precisely makes a lemon a lemon, but it requires the usage of sense to make any real connection with the fruit. There are things out there that we physically cannot sense because we have not adapted a need for them, but I am sure that through sensory implants that hook up to ones brain, we may be able to physically sense things beyond normal human perception. For instance, wifi or radio waves, if an implant were created that could stimulate our brain, suddenly we’ve opened up a whole new sensory range, and of course new emotions or behaviors might develop along with that new sensory perception. I image people would be so over stimulated within a city that they might go insane depending on what sort of stimulation they receive from surrounding wifi waves. In fact people might begin hating the internet because it is everywhere they go. Places they normally consider boring, like a train ride, might provide them an oasis that provides relief.

Everything anyone makes takes advantage of perception and the senses, unless of course what they create is able to evade all human sensory functions. Art created at the microscopic level, art created outside of the visible spectrum, music created at such a high pitch that it is impossible for humans to perceive, anything created outside of the bounds of human sensory perception essentially would not exist unless certain technologies were invented to reveal, in another form to our senses, their existence.

In my own work, I often like creating things that augment human perception, emotions, life, or experience. I think finding ways to extend human experience beyond what is normal makes life more interesting because it gives us new ways to think about and contextualize our existence.

The images bellow are from Asif Khan’s Sochi Winter Olympics installation. This installation takes an image of a visitor and creates a 4D depth map of their face on a massive hydraulic-actuated screen. Whats interesting about this beyond the enormous size of the screen and the technical challenge of manipulated hundreds of hydraulics, is that it gives an ordinary visitor the chance to manipulate the environment and become a participant and put on a show for other observers, at least for a few seconds.

Gentry Demchak's Blog

Works in progress from Design and Technology

Studio: Environments