WEEK 5
E-textiles

The students will have to produce one digital and one analog soft sensor experimenting with the materials available at the lab. They will have to use arduino to read and understand their soft sensor. Try to reproduce the same sensor with different materials/techniques (hard/hard hard/soft soft/soft).

- Create your one digital and one analogue soft sensor

- Program a LED interaction with your soft sensor

- Intergate it in a swatch using hard-soft connections

Class 5

How to make a pressure soft sensor

Inspiration

Is the claim of characterization and foretelling the future through the study of the palm, also known as Palmistry, or in popular culture as palm reading. The practice is found all over the world, with numerous cultural variations. I have always been attracted to alternative mystic techniques based on ancestral oriental cultures. One of them is the reading of the hands to know the future through the natural lines of your hand, these are called by different names such as the line of the heart, the line of life etc.

Design

To make the design in 2D I have based on one of my ceramic palmistri, since it had a simple design and easy to replicate.

Embrodery machine

This week I learned to use digital embroidery machines, in the Fab lab we have the Pfaff creative 3.0 and the brother. In this case use the Pfaff creative 3.0, because it is a bit more advanced than the brother in terms of embroidery techniques.

Settings

You upload the .jpg file to the software of the machine to generate the file compatible with the machine. Once you have the file through a usb the machine uploads it, and you can view the internal settings on the embroidery screen.

Embroidery Palmistry hand

After 10 failed tests trying to understand all the technical issues of the machine, such as types of yarn, type of fabric, the coil, how to juncture the needles etc .. I got a satisfactory final result.

Design Laser cut file

In ilustrator, design the hand to the same extent as the embroidery, to cut in laser with in the conductive fabric.

Laser cut

The tests with the conductive fabric have been positive. The final cutting settings for the epilog laser cutter have been. Speed: 30, Power: 15, Frequency 500hz

Conductive fabric + resistive foam

The layers used in the soft sensor are: Two layers of condictive fabric, one layer of resistive foam, (the velostat has not arrived) and two layers of non-conductive fabric, in this case neoprene, and the embroidery fabric

Fingers

The fingers of the hands were not necessary and they played with the internal conductive threads, so I decided to cut the fingers and only put a conductive cloth in the central part where the hand is going to be pressed.

Conexions

For the first test, I have connected one layer to the positive voltage, and the other layer to the led on the positive leg, the other leg of the led is connected to the negative voltage of 9v. The resistive foam makes the LED does not burn because it gets the conductivity progressively by pressure.

Leds + conductive trhead

The next step is to sew the LEDs in parallel order with conductive thread to the embroidered fabric that will be the upper part.

Sewing parts

Once the LEDs are sewn on the fingers, we also sew all the layers taking into account that the conductive thread does not touch the conductive fabric.

Cutting edges

The palmistri soft sensor is almost finished, just missing the remaining parts of the tissue, to have the hand finished.

Conect to battery

We connect the battery to the hand just like it is test 1 and finally the soft sensor works correctly.

Arduino + pressure sensor

When detecting a flexion in the membrane, the sensor changes its internal resistance. This sensor is made of 2 layers separated by a spacer, the more it is pressed, for example, more active element points touch the semiconductor. Therefore, this causes the resistance to decrease. When it is not pressed, its resistance is approximately 20 MΩ. As shown in the diagram, the red wire represents VCC that is connected to the 5V pin of the Arduino, the black wire to GND, the yellow wires are signal, pin A0 (Sensor) and pin 6 (LED). Therefore, the force or pressure sensor connected to Arduino UNO will remain as shown in the representative figure. You can follow all the steps in this tutorial: Tutorial Pressures sensor MF01

Arduino + palmistry pressure sensor Code File

Once the palmistry pressure sensor is connected to Arduino UNO, I sent the code that modifies the intensity of the LED with the pressure or force applied to the sensor. Finally, it shows the data obtained by the serial port, in this way we can verify that the components work correctly I have correctly connected the pressure sensor to the Arduino board and the program sent is correct, the current data appears in the serial port window. This can be seen, therefore, in the video palmistry pressure sensor.

Results