Sensitive headdress

Sensitive headdress — Documentation

Participants discovered what is a soft electronic circuit by hand sewing: they embroidered with conductive threads small circuits without programing. We explored how ornaments of the traditional Mongolian costumes, such as beads and bells can be turn into soft switches and act on light.

References :

Mongolian culture attaches high importance to ornaments. Ornaments are part of the everyday life, they decorate textiles, buildings, objects and are full of meanings. They are embroidered, painted, printed… This workshop will be dedicated to the connection of the ornaments from garments and beads composing the headdresses. Find more informations in the books listed in Ressources

Mongolia is composed by several ethnies and each of them have their own costumes. 

 

Old photos from early 1900s representing Khalkha married women. Source →

Woman from South Mongolian Üzemchin. National Museum of Mongolia Urjanchai, Ulan Bator.

This videoclip by Altan Urag is the soundtrack of the movie Khadak.

Workshop:

To approach electronic circuits, we figured out what is composing them : 

Electricity is the movement of electrons. Electrons flows and carry electric charges. If you need a reminder →
Current electricity exists when charges are able to constantly flow. To let them flow, you need to create a circuit : a closed and never-ending loop without any insulating gap. Conductors aid the electron flow, but insulators stop this flow.

 

The workshop was dedicated to the difficult meeting between electronic components and textiles. If we want to sew an electronic circuit, how electronic circuits are made usually ? With conductive wire and/or conductive traces on a Printed Circuit Board (PCB).  What are the threads and textiles we can use to create a circuit in textile?

To test if a material is conducting electricity, use a multimeter with the following settings : 

Observe the circuit we stitched : 

We can see a power supply, a led and a switch. Our power supply is a 3V coin cell battery. Schematic of the conductive textile battery holder . We will speak about batteries later but if you want to know more.

Observe our components, what is an LED ?

Led means Light-Emitting Diode. How it works ? A led is composed by two leads, their sizes correspond to the polarization, the long leg is the positive side and the short one the negative side. When the current cross the led, it produces light.How : An LED is a semiconductor, it’s a component between conductive materials and isolated materials. If you look inside your led, you can see that the leads are separated by a space. A material is conductive while its electrons are able to move inside it. In an LED, if you feed it with enough voltage, the positive side loses an electron and this electron goes to the negative side. But it is not stable so the electron comes back to its hole. This movement creates a photon, a photon is light.

To sew a two leads led, bend the legs to use the led as a button.

 

How the switch works ? It opens or closes the circuit. We will create a tilt switch. It is composed by a conductive bead hanging at the end of a conductive thread. This bead will tilt. To close the circuit, it needs to enter in contact with another conductive material. This material will be a small surface of conductive textile. You can design a simple surface but you can create an elaborate pattern. For example, according to the position of the wearer, the circuit will be close or not.

Researches to include the led and the tilt in the circuit. The tilt switches are embroidered complex patterns: a wave  and an ancient ornament with animals. The wave pattern is composed by line forcing the electricity to navigate from one side to another, it will had resistivity to the circuit. The inside of the ancient ornament will be fully embroidered by the student, it will help the current to go straight to the other point. 

While stitching the circuit, students double check their circuits with the multimeter. 

Students explain to each others issues they had while making their circuits and they helped each others to fix these according to their fresh experiences. Typical troubles were caused by wrong polarities or short circuits.  

To limit the resistivity of the embroidered pattern shown before, the student first used conductive textile from Shieldex to ensure the circuit. Then, she embroidered details at home. 

This student used chain stitches to make the circuit — but be careful with conductive wire making short circuits ! 

To introduce the use of resistors in electronic circuits, we described how Lilypad leds are designed.

What is Lilypad ? Lilypad components are design to discover electronic textiles, they are educational tools. These small devices are design to be sew on textile with conductive threads. If we look closer, on each sides of the PCB we have conductive areas. This area is design to sew the components with a conductive thread. Then we have the tiny components, tiny components design for PCB are called Surface Mount Devices or SMD. This components are a LED and a resistor. We can see the connections : from the positive side to the led, to the led to the resistor and from the resistor to the negative side.

 

Students get in touch with SMD LEDs and resistors : 

 

Following the next settings, they measured  the various resistors available : 

Look closer the document summing the different LEDs available for the workshop : 

This document synthesizes the most important data available in the datasheets of each component. In this document you can find for each LED, its size, its luminous intensity in candelas, the amperes and voltages it need to glow. 

 

 If you want to use a bigger battery and if you want to include a lot of LEDs, you need to calculate the resistors you need. 

 

Components can be in series or in parallel.  Now we will stitch the following circuit : 

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