Example Projects
Workshops
Announcements
Actuators
Connections
Power
Sensors
Traces
Circuits and Code Wireless

Conductive Materials
Non-Conductive Materials
Tools
Techniques
Thinking Out Loud
Tools
  • ATtiny Breadboard Programming Piggyback Extension
  • ATtiny Programming Shield
  • Breadboard Pincushion
  • Circular Knitting Looms
  • Circular Knitting Machines
  • Circular Sock Knitting Machines
  • Circular Weaving Looms
  • CNC Textile Machines
  • desoldering wick
  • Dino-Lite digital USB microscope
  • Fabric Markers
  • Fabric Scissors
  • File
  • Hole Maker
  • Craft Iron
  • ISP Alligator Clip Extension
  • Laser Cutter
  • LilyPad SnapRing
  • Needle Threader
  • ohmBroach
  • ohmGlove
  • ohmHook
  • ohmTranslator
  • Pincushion Breadboard Bracelet
  • Pompom Maker
  • Popper Machines
  • CNC Milling Machine
  • Resistance Visualization Tool
  • Seam-Ripping Continuity Meter
  • Sewing Machines
  • Knitting dolly
  • Spudger
  • Thin nose pliers
  • Vibrating Crochet Hook
  • Vinylcutter
  • Wire Wrap Tool
  • About
  • E-Textile Events
  • E-Textile Spaces
  • Newsletter
  • Print & Publications
  • Shopping Local

  • SEARCH
    Content by Mika Satomi and Hannah Perner-Wilson
    The following institutions have funded our research and supported our work:

    From 2013-2015 Mika is a guest professor at the eLab at Kunsthochschule Berlin-Weissensee

    From July - December 2013 Hannah was a researcher at the UdK's Design Research Lab

    From 2010-2012 Mika was a guest researcher in the Smart Textiles Design Lab at The Swedish School of Textiles

    From 2009 - 2011 Hannah was a graduate student in the MIT Media Lab's High-Low Tech research group led by Leah Buechley


    In 2009 Hannah and Mika were both research fellows at the Distance Lab


    Between 2003 - 2009 Hannah and Mika were both students at Interface Cultures
    We support the Open Source Hardware movement. All our own designs published on this website are released under the Free Cultural Works definition
    Tools

    ohmHook

    The ohmHook is crochet hook mounted on a circuitboard which measures the electrical resistance between the crochet hook and a crocodile clip connected to the opposite end of the tool handle. The resistance is displayed as the 10 bit reading of the microcontroller’s analog-to-digital converter.

    Having the ability to sense electrical properties of a material as you are manipulating it can allow you to explore it’s potential for creating electronics. Highly conductive materials make good connectors between physically distant electronic parts. Materials with stable electrical resistance can be used to detect location of contact on their surface. Materials with varirable resistance often respond to forces such as stretch, pressure, bend and twist with a change in resistance, and can be used to sense a large variety of physical interactions.
    The ohmHook does not have to be used for crochet. Use it to probe and explore all kinds of materials, and to invent new ways of building electronics.


    Attention! There is one big mistake in the design that I need to change in a next version.
    when the potentiometer is turned all the way down to 0 ohm and you touch the probes (hook and alligator clip) directly together (with no resistance in between) you are creating a short circuit between +3V and -GND. The heat of this short circuit can be strong enough to burn the resistive track inside the potentiometer. One way to solve this would be to use a potentiometer that does not go all the way down to 0 ohm. Or to add another small 100 ohm resistor in series with the potentiometer…

    Photos:
    Photos (version 1) >> https://www.flickr.com/photos/plusea/sets/72157664482745526
    Photos (version 2) >> https://www.flickr.com/photos/plusea/sets/72157664860355161

    Links:
    >> ohmHook Booklet
    >> ohmHook DIY Page
    >> ohmHook Project Page
    >> ohmHook Workshop Documentation
    >> ohmHook Repository

    Materials and Tools

    Circuit Diagram

    HCMS-29xx datasheet >> http://www.avagotech.com/docs/AV02-0868EN
    ATtiny84 datasheet >> http://www.atmel.com/Images/8006S.pdf
    Slider datasheet >> http://www.mouser.com/ds/2/54/tl-777483.pdf

    ATtiny Programming

    Using ATtiny programmer with Arduino 1.6:
    Install ATtiny files >> http://highlowtech.org/?p=1695
    Install ATtiny driver (windows only) >> http://highlowtech.org/?p=1801

    Code

    Download library >> http://www.pjrc.com/teensy/td_libs_LedDisplay.html
    Close Arduino
    Edit .h file >> https://forum.arduino.cc/index.php?topic=394297.0
    Open Arduino

    /*
    ohmHook – measuring and manipulting resistance by hand
    for the E-Textile Tooling workshop at Eyeo 2016
    >> www.github.com/plusea/ohmHook

    displays an analog value on an Avago HCMS-39xx display controlled by ATtiny84
    original HCMS-39xx display code by Tom Igoe, created 12 June 2008
    modified by Hannah Perner-Wilson Apr 2016
    */

    #include

    // Define pins for the LED display:
    #define dataPin 1 // connects to the display’s data in
    #define registerSelect 2 // the display’s register select pin
    #define clockPin 3 // the display’s clock pin
    #define enable 8 // the display’s chip enable pin
    #define reset 9 // the display’s reset pin
    #define displayLength 4 // number of characters in the display
    LedDisplay myDisplay = LedDisplay(dataPin, registerSelect, clockPin, enable, reset, displayLength); // create am instance of the LED display library:
    float brightness = 15; // screen brightness

    #define buttonPin 5
    #define potMinus 6
    #define analogPin 7
    #define speakerPin 10

    int buttonState = 0; // variable for reading the button status
    int lastButtonState = 0; // stores the previous state of the button
    int mode = 0; // mode will store the current blinking mode (0 – 3)
    int myDirection = 1; // direction of scrolling. -1 = left, 1 = right.
    int analogValue;
    float resistanceValue;
    float soundValue;

    void setup() {
    pinMode(buttonPin, INPUT_PULLUP);
    pinMode(analogPin, INPUT);
    pinMode(potMinus, OUTPUT);
    digitalWrite(potMinus, LOW);
    pinMode(speakerPin, OUTPUT);

    delay(500);
    noise(speakerPin, 100, 200);
    noise(speakerPin, 20000, 200);
    delay(10);

    myDisplay.begin(); // initialize the display library:
    myDisplay.setBrightness(brightness); // set the brightness of the display:
    myDisplay.clear();
    }

    void loop() {

    // BUTTON //
    buttonState = digitalRead(buttonPin); // read the state of the pushbutton

    // detect the event of the button going from pressed to not pressed,
    // and increment the animation mode when this is detected
    if (lastButtonState == HIGH && buttonState == LOW) {
    mode = mode + 1;
    }

    lastButtonState = buttonState; // store current button state as the last button state to use next time through loop()
    if (mode > 8) mode = 0;

    ///// MODE: ANALOG READ /////
    if (mode == 0) {
    pinMode(potMinus, INPUT);
    mode = 1;
    }
    if (mode == 1) {
    analogValue = analogRead(analogPin);
    delay(10);
    // DISPLAY //
    myDisplay.setCursor(0); // set the cursor to 1:
    if (analogValue < 1000 && analogValue > 99) myDisplay.print(” “);
    if (analogValue < 100 && analogValue > 9) myDisplay.print(” “);
    if (analogValue < 10) myDisplay.print(" "); myDisplay.print(analogValue, DEC); } ///// MODE: SYNTH ///// if (mode == 2) { myDisplay.setCursor(0); // set the cursor to 1: myDisplay.print("SYNT"); mode = 3; } if (mode == 3) { analogValue = analogRead(analogPin); if(analogValue < 1010){ soundValue = map(analogValue, 0, 1023, 0, 20000); noise(speakerPin, soundValue, 1); } } ///// MODE: POT RESISTANCE VALUE ///// if (mode == 4) { // READ POT // pinMode(potMinus, OUTPUT); digitalWrite(potMinus, LOW); mode = 5; } if (mode == 5) { analogValue = analogRead(analogPin); delay(10); resistanceValue = map(analogValue, 1023, 0, 0, 500000); // DISPLAY // myDisplay.setCursor(0); // set the cursor to 1 //myDisplay.print(analogValue, DEC); if (resistanceValue >= 450000 && resistanceValue < 500000) myDisplay.print("500K"); if (resistanceValue >= 400000 && resistanceValue < 450000) myDisplay.print("450K"); if (resistanceValue >= 350000 && resistanceValue < 400000) myDisplay.print("400K"); if (resistanceValue >= 300000 && resistanceValue < 350000) myDisplay.print("350K"); if (resistanceValue >= 250000 && resistanceValue < 300000) myDisplay.print("300K"); if (resistanceValue >= 200000 && resistanceValue < 250000) myDisplay.print("250K"); if (resistanceValue >= 100000 && resistanceValue < 200000) myDisplay.print("200K"); if (resistanceValue >= 50000 && resistanceValue < 100000) myDisplay.print("100K"); if (resistanceValue >= 40000 && resistanceValue < 50000) myDisplay.print(" 50K"); if (resistanceValue >= 30000 && resistanceValue < 40000) myDisplay.print(" 40K"); if (resistanceValue >= 20000 && resistanceValue < 30000) myDisplay.print(" 30K"); if (resistanceValue >= 10000 && resistanceValue < 20000) myDisplay.print(" 20K"); if (resistanceValue >= 5000 && resistanceValue < 10000) myDisplay.print(" 10K"); if (resistanceValue >= 1000 && resistanceValue < 5000) myDisplay.print(" 5K"); if (resistanceValue >= 500 && resistanceValue < 1000) myDisplay.print(" 1K"); if (resistanceValue >= 100 && resistanceValue < 500) myDisplay.print(" 500"); if (resistanceValue >= 0 && resistanceValue < 100) myDisplay.print("<100"); } ///// MODE: BRIGHTNESS ///// if (mode == 6) { brightness = map(analogRead(analogPin), 0, 1023, 1, 15); delay(10); brightness = constrain(brightness, 1, 15); myDisplay.setCursor(0); // set the cursor to 1: myDisplay.setBrightness(brightness); // set the brightness of the display //myDisplay.print(brightness, DEC); myDisplay.print("LITE"); } ///// MODE: JOKES ///// if (mode == 7) { myDisplay.clear(); myDisplay.setCursor(0); myDisplay.setString("resistance smells funny!"); mode = 8; } if (mode == 8) { if ((myDisplay.getCursor() > displayLength) ||
    (myDisplay.getCursor() <= -(myDisplay.stringLength()))) { myDirection = -myDirection; delay(500); } myDisplay.scroll(myDirection); delay(100); } } void noise (unsigned char noisePin, int frequencyInHertz, long timeInMilliseconds) { int x; long delayAmount = (long)(1000000 / frequencyInHertz); long loopTime = (long)((timeInMilliseconds * 1000) / (delayAmount * 2)); for (x = 0; x < loopTime; x++) { digitalWrite(noisePin, HIGH); delayMicroseconds(delayAmount); digitalWrite(noisePin, LOW); delayMicroseconds(delayAmount); } }

    Improvements for a Next Version

    – shift cap closer to microcontroller
    – connect holes for tip hook loop to probe pin
    – clean up silkscreen
    – add on/off markings to back


    Photos

    Flickr set >> https://www.flickr.com/photos/plusea/albums/72157664860355161



    Leave a comment