FINISHING EVERYTHING UP
On this last week of the project, all the loose ends are being tied up. It was a very intense week, with a lot of "I should have done this earlier" thoughts and also many interesting adventures, both with the PCB board, the sewing and assembly of the electronics and the final video production. A very eventful and fun week. Not very relaxing..
INSPIRATION
I'm inspired by completion, and a lot from the people in the e-textile field who are rocking the scene with their work. In particular, I was inspired by the work of Kobakant, Meg Grant, Tricia Flanagan, Ricardo O'Nacimento and the e-textile community at large.
OBJECTIVES & PLAN
The focus of this week is FINISHING EVERYTHING. Here is what I executed
- FINALIZING PCB MILLING & ASSEMBLING COMPONENTS ON PCB
- Translating the Design on Fab Modules
- Trial and Error Milling the PCB
- Soldering Arduino Pro Mini, resistors and transistors to the board
- MAKING TEXTILE PRESSURE SENSOR + TEST
- Cutting the fabric + Eontex fabric
- Sewing the sensor together
- Testing its shift in resistance on circuit (and realizing it doesn't work)
- MAKING NEW VIBRATION MOTOR CASES
- Assessing the solid motor cases are too bulky
- Sewing neoprene motor cases + adding 3D printed lid
- MAKING NEW PRESSURE SENSORS
- Cutting new fabric for sensors
- Wrapping around copper tape
- Sewing the sensors together
- Testing them on circuit (they work!)
- ASSEMBLING ELECTRONICS ON THE TOP & SEWING CONDUCTIVE TRACES
- Soldering cables to the PCB
- Sewing PCB on the top
- Sewing pressure massage modules (sensor + vibration motor)
- Connecting PCB pins to massage modules
- Sewing LEDs on embroidered heart
- Connecting LEDs to PCB pins
- CODING ARDUINO
- First Attempt
- Second Attempt
- MAKING VIDEO
- Finding an actress and video team
- Shooting and editing
FINALIZING PCB MILLING & ASSEMBLING COMPONENTS ON PCB
INGREDIENTS
- Fab Modules software
- Roland Monofab SRM 20
- 1 Copper PCB board
- 4 Resistors 2.2 KOhm
- 4 Transistors SMD KTC3875
PROCEDURE
The first step was , after designing the PCB on the software Protheus, to upload the .png file to the MIT based software Fab Modules. Fab Modules provides the interface where we can translate the PCB design to a ready to mill file. The way it works is that it recognizes the black to white transition corresponding to where the circuit line starts in the .png file and transforms it into a line, which will be used by the CNC machine to mill the circuit lines. Some of the parameters were a bit tricky to deal with. Specifically the number of offsets is by default 4, which was overlapping other lines int the circuit. We changed that a few times and ended up using number of offsets 2.
In addition, the tool diameter was originally 0.4, which we changed a few times until we reached the ideal value to 0.2.
The different values were evaluated by milling the PCB with the Roland Monofab SRM 20. The tool to mill the circuit lines in the PCB was not ideal, and risked breaking more than once. In the end, after a few iterations, we managed to get the PCB out successfully.
We had to cut the PCB manually with a saw, and drill the holes with a small drill.
Once the PCB was finally ready, it was time to solder the Arduino Pro Mini, the four 2.2 K Ohm resistors and the 4 transistors 4 Transistors SMD KTC3875 to the board. We also added pins to the Arduino board so that we could use an FTDI cable to upload the code.
Soldering the small pieces on the small circuit was a bit challenging, but it was completed successfully. The next step would be to solder the cables to the remaining parts so they could be connected to the sensors + actuators in the garment.
RESULTS & REFLECTIONS
I am very grateful for the strong support received by Jesús Garduño in this step, thanks to which I was able to learn how to design and mill a PCB board without any previous knowledge. My next iteration will have a soft PCB and I'm very excited to experiment with that.
MAKING TEXTILE PRESSURE SENSOR + TEST
INGREDIENTS
- Cotton
- Velostat
- Eontex conductive stretch fabric
- Laser Cutter
- Thread and Needle
- Two-face tape
PROCEDURE
We finally got in the mail the much expected Eontex conductive stretch fabric, so I was ready to make the pressure sensors with it. I used this tutorial from Plusea on Instructables, which is an easy way to make a nice soft pressure sensor.
I cut the cotton pieces with the laser cutter, after designing them on Rhinoceros. I simply designed a circle and two rectangles and used the commands trim and join to make a single shape. I exported the shape with File > Export Selection > .dxf
With the laser cutter I used the following parameters
- Speed 16
- Power 28
I cut the Velostat circles by hand with scissors, making them 0.5 cm smaller in radius. After that, I cut the Eontex conductive stretch fabric part as a circle with a small rectangle coming out of it on one side. This piece was about 0.3 cm smaller in radius than the Velostat circle, to ensure the conductive fabric pieces wouldn't touch each other.
I then sewed the Eontex conductive stretch fabric to the cotton outer layer by hand. Next I sewed the Velostat layer on top of the conductive fabric. I sandwiched two of the cotton+Eontex+Velostat layers an sewed them together. Ta-dahh! The pressure sensors are done. I made 2 of them then decided to test them.
When I tested the pressure sensors with the existing circuit I already had, I discovered a dissappointing truth: the Eontext pressure sensors worked a lot worse than the copper tape ones. I had to find out why, so I checked the difference in resistance value when pressed vs not pressed. I discovered that the difference in those two values was very little, making the pressure sensor quite inefficient. The LEDs wouldn't light up properly, and the vibration motors also weren't performing at full power.
RESULTS & REFLECTIONS
The great expectations held for the Eontex fabric were met with failure. The fabric didn't behave effectively for the purpose of a pressure sensor, and it underperformed in comparison to the copper tape sensors. I conclude that the fabric is better suited for stretchable sensors, and will make new pressure sensors using the copper tape.
MAKING NEW VIBRATION MOTOR CASES
INGREDIENTS
- Dremel Drill
- Neoprene
- 3D printed lids
- Thread & needle
PROCEDURE
First of all, I had to make sure the 3D printed lids with the massage "teeth" would be able to be sewn together with the soft part. The initial design called for glueing the lid to the 3D printed case, but now the case was going to be made in Neoprene. So I took a Dremel drill with a very fine point, and made 6 holes on each lid, to sew them to the Neoprene.
After that. I used Rhinoceros to make a circle, about 0.5 cm wider in diameter than the lid, so 1.7 cm. I then exportd the file in .dxf and upladed it to the softaware to laser cut 8 circles in white Neoprene with the following settings.
- Speed 12
- Power 35
Once the circles were ready, I sewed them together by hand, leaving a side open enough to enable the Lilypad vibration motor to slide inside and for the + and - pins to be sewable with the conductive thread.
Lastly, I sewed the lid on top of the Neoprene with black thread. Now the vibration motor containers are ready.
RESULTS & REFLECTIONS
The process was fairly simple and the result very effective. I reduced the size of the motor containers by about 2 mm, but more importantly I removed the sharp corners of the solid container and made the whole piece softer, while keeping the rigid teeth. At the touch, it feels a lot more pleasant when pressing it.
MAKING NEW PRESSURE SENSORS
INGREDIENTS
- Cotton
- Scissors
- Copper Tape
- Neoprene circles
- Thread & needle
- Two-face tape
PROCEDURE
The new soft pressure sensors were an upgrade from the ones created in S1 / W1 , where i had used a thick brown paper and kept the Velostat as the most external layer. In this case the copper tape was wrapped around a piece of cotton, cut out as a circle with a rectangular side sticking out. For each pressure sensor I made and layered as follows:
- 1 external cotton layer
- 1 Velostat circle
- 1 Cotton layer with copper tape
- 1 Velostat circle
- 1 Velostat circle
- 1 Cotton layer with copper tape
- 1 Velostat circle
- 1 external cotton layer
I sewed them all together.
Once the pressure sensors were ready, I sewed each of them to the vibration motor case. This way the massage module would be complete and compact, with no risk of movign around in weird ways.
RESULTS & REFLECTIONS
The final pressure sensors worked magnificently with the circuit. The range in resistance change was pretty wide ensuring that the pressure would be detected well without the pressure sensor being neither too sensitive of too stiff. After 3 iterations finally complete!
ASSEMBLING ELECTRONICS ON THE TOP & sewing conductive traces
INGREDIENTS
- Assembled PCB
- Voronoi layer in techno fabric
- Lace
- Tulle
- Cables
- Conductive thread
- Thread & needle
- Lilypad LEDs
- Massage modules (pressure sensors + vibration motors)
- Heart embroidery
- LiPo Battery
PROCEDURE
The fun part starts here. I had all the electronics ready, and the only thing missing was putting it all together to have the garment ready for the video and user test.
First of all, I assessed the best position and orientation of the PCB on the space where the heart would be. I also assessed where the massage modules should go to ensure I would make the most effective connections with the conductive thread.
I then soldered cables to all the pins that had to be connected respectively to the pressure sensors, vibration motors and LEDs. As usual it's a bit laborious, but I got some good practice in and made the connections pretty solid.
After that, I sewed the PCB to the techno fabric on the 4 corners. I then created a little loop with the copper coming out from each cable, and soldered it so the loop could be used to sew the conductive thread to it and make the connection.
I then sewed the connections to each side of the pressure sensor with the conductive thread to the respective pin on the PCB. I made sure I sewed my connections in a way that I didn't have any overlapping threads. Then I sewed the + and - of the 4 vibration motors to the respective + and - pins of the pins on the PCB. I had to overlap my thread only once and I used a bridge made out of neoprene to ensure the 2 conductive paths would not overlap and create a short circuit.
Once these parts were sewn, I had to sew the LEDs. In order to ensure that I wasn't going to overlap the sewn circuits of the LEDs with the other ones, I put an extra layer of techno fabric in between the heart embroidery and the PCB. I then sewed the paths on the back side of the heart, so the techno layer would act as an insulating sandwich. It was a bit complex but it was effective. At this point the circuit was ready. I would use a cable for e battery in this iteration which would connect directly to the GND and Power pins.
RESULTS & REFLECTIONS
Sewing the circuit was definitely one of the trickiest challenges of this project. Not because if its intrinsic difficulty, but because of the sheer amount of cables and pins I had to sew. The hardest part was sewing the massage modules positioned on the back of the top. The path to sew was long and the chance to overlap or confuse the paths was great. But I managed to handle it pretty well.
ARDUINO CODING & UPLOADING
INGREDIENTS
- Arduino IDE
- FTDI cable
- Arduino Pro Mini on PCB
PROCEDURE
RESULTS & REFLECTIONS
MAKING VIDEO
INGREDIENTS
- Assembled top
- Model
- Camera woman
- Video Editor
PROCEDURE
For this part of the project I decided to collaborate with two girls from Merida who study multimedia design, Mirley Ruiz and Name. Both of them are very keen on developing their video making skills, so I thought it would be fun to make the video together.
I initially brainstormed with Mirley the storyline of the video, in order to ensure it would be impactful in max 5 minutes of time, while at the same time be descriptive . I wanted to make sure the audience would understand:
- WHAT ISSUE
- WHAT SOLUTION
- HOW IT WORKS
- USER FEEDBACK
Once we created the video script, i got help by a Alejandra Diaz, who's working at the Fablab and whom I found perfect to be my actress and user. We shot the video at Fablab Yucatán, and during the video shooting we took the occasion to perform a user evaluation of the garment. The question asked to Alejandra were the following:
- How does it feel?
- When would you use it?
- What would you improve?
The evaluation went quite well and I am planning to evaluate the product with other users as well to gather further feedback.
With Mirley's help, I got the video edited for the first draft in less than one day, which was a great achievement. During the final presentation, a few items of the video stood out as needing a bit of improvement in regards to the audio and the length of the user experience part. The second iteration of the video refined these aspects, which you can watch here.
RESULTS & REFLECTIONS
It was very fun to plan the video together and shoot it as a team. Because a lot of this project was individual work and I love to work in a team, I really enjoyed it. Especially learning about other designer's creative approach and process. It was a very nice outcome and I am satisfied with it.
