Prototype 4: Materials as Sensors

Weight-Sensitive Canvas Bag

Key Image



I embroidered this tote bag using alpaca yarn, my favourite fibre.



In this project the canvas bag lights sewed at the front of the canvas bag indicate the weight being carried inside the bag. There is a scale of lights depending on the weight placed inside. The first light turns on to indicate there is something in the bag, the second light will turn on when more weight is added, and the third light indicates the maximum weight has been reached.

Sensor was made with two layers of aluminum foil separated by a layer of velostat. I glued aluminum foil to velostat in the four corners on each side and covered this with a sleeve made of non-conductive fabric. Sensor’s input goes through pin A2 and output to LED lights goes through pins A1, A3 and A7.

The sensor is placed at the bottom of the canvas bag, so when some weight is placed on the bag and a person lifts it, LED lights will go on depending on the weight of the bag.

Parts and Materials List


  • Adafruit Circuit Playground Express
  • Resistor
  • Sewable LED lights
  • Li-Ion Poly 1200mAh battery


  • Aluminum foil
  • Velostat
  • Non-conductive fabric
  • Alligator-clip jumper wires
  • Conductive thread
  • Non-conductive thread
  • Canvas bag embroidered with Alpaca yarn


  • Scissors
  • Glue gun

Circuit Diagram



See code here.


wa4_step01 Step 1
Cut a piece of velostat and two pieces of aluminum foil. Fold aluminum foil to match the size of the velostat, leaving a narrow tip out for connectors.
wa4_step02 Step 2
Aluminum foil was glued to each side of the velostat in the four corners, so glue does interfere with flow of electricity between the two layers of aluminum foil.
wa4_step04 Step 3
Sensor is covered with non-conductive fabric to isolate the sensor and avoid short circuits. Fabric is thick, so it provides some cushion too. Fabric is stitched on the sides to make a sleeve that will cover the sensor.
wa4_step03 Step 4
Next is to fix the Circuit Playground Express and connect LED lights. I used both conductive and non-conductive thread.
wa4_step05 Step 5
The Circuit Playground Express board is stitched at the top of the bag using non-conductive thread.
Step 6
Lights are stitched and connected to the corresponding “pins” in the Circuit Playground Express board using conductive thread.
Step 7
Sensor is placed at the bottom of the canvas bag and connected using alligator-clip jumper wires. Also, battery is connected to the Circuit Playground Express board.



My LED Basket Handbag


My Prototype 3: Digital Switches for Embodied Interactions My LED Basket Bag

I decided to use a basket bag to experiment the prototype of three switchers which are activated through the use of LEDs. There are two body environment switches such when someone hold the basket bag handles and fairy lights become activated, and when the bag is opened a switch located at the bottom of the bag activate LEDs place inside the bag. The other category I can call clothing gesture because the bag has a button that helps to lock up safely through a loop, then when bag is close with the loop LED’s light are activate by a switch

Circuit Diagram

We have three circuits for the digital switches –red, blue and yellow, each of them representing a set of lights, the yellow representing a set of fairy lights– and three circuits to power the LED lights. Pins D2, D3 and D4 are used for the digital switches and ports D11, D12 and D13 are used to power the LED lights. Of course, this diagram is a simplified version, because the wiring inside the handbag depended on space and positions of switches and LED lights (we use sets of light for every switch and the wiring had to satisfy these requirements).

Here detailed hand made diagram of the wiring for each switch.

Arduino Source Code
Code can be found in GitHub (see here).


A. Handle: Body/Environmental Switch

When a person holds the handbag by the handle, the handle will be illuminated with a strip of fairy lights. When the user releases the handle, the light will go off.
The switch was made using copper adhesive tape, which is wired to an board mounted on a using flexible wire. To make the bridge I used copper tape and a red cloth where I adhered the tape and when I hold the handle with this cloth the bridge activated the circuit and switch then lights were on. The Arduino card and all the connection were place inside the basket bag.


Overall, all the switches worked well, although there are some reflections which are applicable to all three switches because they use similar materials and have similar connectivity. First, I do not like the connections are so visible, I would like to something more subtle, but I am still learning and prefer to be more comfortable with connections that the appearance for now, but this look bother me
About the wiring and switches can be further refined, copper tape is easy to manipulate plus its flexibility helped me to attach to a surface such the basket which is hard but not enough to keep stick in place, sometimes the tape didn’t stick well and if I moved the basket so much the connectivity could get lost and stop working, maybe using conductive fabric could be a better option.
Another point perhaps is the use of a full-size breadboard and the Arduino Nano 33 IOT
This bord is large and with the battery connected are heavy to place inside the bag. Maybe using the Adafruit’s Circuit Playground Express would have been better, but I think using the Arduino Nano to make this prototype is probably fine, but it is good I can realize about what I like and what I do not like to make better choices for my final work.

Material used in this prototype

Arduino Nano 33 IOT
Adhesive copper tape
Fairy Lights
Rechargeable 5V battery
Stranded wire cover with silicone
Basket Bag
Piece of red cloth





See full video here.

B. Button Up: Clothing/Gestures Switch

The handbag is “locked” with a loop and a button. When a person closes and locks the handbag by placing the loop around the button, two LEDs at the centre exterior surface of the handbag will go on. When a person opens the handbag by releasing the loop around the button, the exterior light will go off. The connections were using copper tape and stranded wire cover with silicone because was very thin and flexible. The switch was located along the loop then when the bag was button up the contact between the button and loop activated the switch and LEDs were on.




These reflections are almost the same I stated above on the handle switch, all the switchers used similar materials and have similar connections. First, I do not like the connections are so visible, I would have preferred something more subtle, but I am still learning and prefer to be more comfortable with connections than the appearance for now, but the look still bothers me.
About the wiring and switches, they can be further refined. Copper tape is easy to manipulate and its flexibility helped when attaching to the basket surface. However, the continuous movement of the bag caused the tape to move and, in some cases, detach from the basket surface, which caused loose connectivity. Again, definitely using conductive fabric could be a better option.
Another point perhaps is the use of a full-size breadboard and the Arduino Nano 33 IOT. That plus the battery was large and heavy to place inside the bag. Maybe using Adafruit’s Circuit Playground Express would have been a better alternative. I also need to do more research about the wireless options available in the Arduino Nano, which may help reduce some wiring. I am happy with the outcome, but not so much with the visible connections.
In terms of usability, I think it would be better to reverse this switch. The idea is that if a handbag is unattended and somebody opens it, a LED light will go on as some kind of alert. I would also like to add a sound, but that required to a speaker to the configuration which I still do not have. Another option would be to send a message to a device (a phone), but that would require an application listening.

Material used in this prototype

Arduino Nano 33 IOT
Adhesive copper tape
LED lights
Rechargeable 5V battery
Stranded wire cover with silicone
Basket Bag
I use practically the same material for all the three switches, but here instead of fairy light I used LEDs



See full video here

C. LED’s Inside Basket Bag: Clothing Gestures

When a person opens the handbag, a set of lights will go on to illuminate the interior of the handbag. When the handbag is closed, the set of lights inside will go off.
It is always handy to have light inside a handbag if the owner is looking for something inside. The circuit in this prototype was build in a similar way than the other two switchers. Here the switch is placed at the bottom of the handbag, then when the handbag opens the upper and bottom part of the handbag activates the switcher. The copper tape makes contact and LEDs go on.




Overall, the switch worked well, similar reflections that I made for the previous prototypes applied here too. There is also room for improvement, my big take here is to use conductive fabric and a smaller board like Adafruit’s Circuit Playground Express.

Material used in this prototype

Arduino Nano 33 IOT
Adhesive copper tape
LED lights
Rechargeable 5V battery
Stranded wire cover with silicone
Basket Bag


See full video here



See full video here

LED Heart Alpaca Bracelet by Hortensia Reyes


LED Heart Alpaca Bracelet by Hortensia


I love alpaca fibre, is soft, light, breathable and hypoallergenic. I weaved this bracelet while trying to learn how to weave. I love textile jewelry because wearing them are very comfortable, I made a necklace of alpaca fibre too.


Now I tried to incorporated lights to this bracelet to see how it looks.

In this project I used fairy light strip and shaped as a heart, I sewed these light on top with regular thread of the bracelet. The “heart” lights fade following a heartbeat and inside the “heart” there are three groups of blinking sewable LED lights. The LED lights blink at three different rates: slow, medium and fast blinking. The piece represents a beating, sparkling heart –a sign of love– and lighting is applied on top of an alpaca bracelet but I sewed these lights under the bracelet, then light come through the textile, I want to have a subtle light, not so intense. I like how the light were show all together.

The fairy light strip and each group of LED lights have its own connection to the Arduino Nano 33 IoT board. Each connection uses a different port on the Arduino board for the positive, that way the program can apply the corresponding effects and blinking or fading rates. The Arduino code combines the fading and blinking basic examples, but uses proportional refresh rates for fading and blinking, since multiples delays did not produce the desired effect (delays accumulate and fading and blinking became all too slow).

The piece is quite light, around 100g, which meets the weight wearability criteria for the wrist by Clint Zeagler’s video (Zeagler, 2018), which specifies under 0.5lb for this part of the body.

Since I started testing the circuits using the Arduino Nano 33 IoT, I learnt the final result did not meet the portability criteria to be strictly wearable. Perhaps the Arduino Nano 33 IoT was not the best board selection, because it has been designed to be used on a breadboard or a socket, not precisely a sewable board. I know the Adafruit’s “Circuit Playground Express” would have been a much better option, since it does not have pins and it has holes that can be used to be sewed on a piece of fabric. This board could have been powered with two 3V coin batteries, which would have been enough for low power lights like the ones I used, and this would have met the portability criteria for wearability. The most important for me doing this prototype was learnt how to do the connectivity, build circuits and try to use the Nano 33 IOT which I never used in my life.

Prototype Image 1

Detail Image 1

Detail Image 2

Prototype Image 2

Prototype Image 3
Part & Materials

Alpaca weaving bracelet
Full-size breadboard
Arduino Nano IoT 33
Through-Hole resistors
Conductive thread
Regular thread
USB cable
5 Pink LilyPad LED
2 White LilyPad LED
Fairy lights
Arduino Code

Circuit Diagram

Below the circuit diagram. As you can see, there are three sets of LED lights inside the heart, this was made with the fairy light strip. Each set of LED lights as well as the fairy light strip have their own red wire (positive), which connects to a different port in the Arduino board, that way they can get different effects each.

Each red wire line does not touch each other, also red and black wires do not touch. We are using a USB portable charger showed on the diagram below to power this project, but for this project to be wearable we would probably have to use a set of coin batteries.

Testing my LED circuit
Demo Video

“Light-up LED Cuff / Bracelet With Magnetic Switch (e-textile)” (Dawson, 2017)
When I started with this project, I tried to find simple guidelines to understand how to connect and sew conductive thread to integrate into my textile (weaving). I found this helpful website, easy to follow and with clear directions, maybe too easy to understand because it was a project for primary school students, but it was good for my first prototype. I watched the video tutorial that help me on doing my sewing with the conductive thread. I recommend this to anybody who is pretty new on e-wearability.

“Making a Face Mask with ANIMATIONS!!” (Nedforge, 2020)
This was the design that inspired me for this project. Although I did not do a face mask and did not use the LED Matrix, which was built with individual addressable LED strips, this was an interesting project. I did not know the LED Matrix and the supporting software existed. On the down side, welding was required for this project and I do not have a soldering iron yet. The idea of light animation inspired me to use sewable lights in my bracelet. Maybe in my next project I could use a LED Matrix to create more light animations.
“Actualizer: LED Bracelets” (Actua Canada, 2016)
This was the terrible animation, because although was a simple project like the the first example “Light -Up Led Cuff” the explanation was not clear, the video helps but the explanation was unclear, the design was very sloppy and there is not a list of the material needed to make this project. I think is because the first example was address to school students the demonstration, video, photos and list of materials was clear like a lesson for students in the classroom which could be used for a school teacher to do this project in class.

Actua Canada; “Actualizers: LED Bracelets”. September 20, 2016. In:

Dawson, Jill; “Light-up LED Cuff / Bracelet With Magnetic Switch (e-textile)”. 2017. In:

Nedforge; “Making a Face Mask with ANIMATIONS!!”. May 12, 2020. In:

Zeagler, Clint; “Where to wear it”. July 15, 2018. In: