Open Project: Cardi Belt – Marcus Tang



As a forgettable person, I usually tend to lose day-to-day objects and spend quite some time trying to find them, such as my whole wallet left at my workplace I found out once I got home that my keys were attached to it. For the sake of losing things without realizing it. I would create a wearable that could give out a reminder when I lose the object. While not trying to reach for complicated mechanisms such as Bluetooth tracking (just like apple tags), the objective was to do a warning before really losing it.


Concept: (Idea and what are you creating)


The concept for the piece would be a cardholder with an alarm feature. Using a simple conductive fabric switch as the main trigger. After pulling out the card, the user has to put the card back within the given time (40 seconds), or else the alarm will go off (with a tiny light show!). 




To make the cardholder wearable, I put leather strips at the back of the cardholder so it could connect any wearables that have a strap to hold on to. With the minimalistic design, this prototype only carries out one mission which is to safely secure your card.



Circuit sewing was done after drawing the diagram on the felt fabric. the felt fabric was separated into two layers and the trigger mechanism is by removing the card and making those two conduct together hence activating the alarm countdown sequence. 




For the Materials, I mainly use felt fabric and faux leather for making the prototype. I used felt to be the canvas when sewing with the conductive threads and drawing the circuit diagram with a Sharpe. Then it was wrapped into a popsicle panel that I made to make the whole structure more steady and wouldn’t collapse. At last, The whole layer is sewed and wrapped in faux leather for a wallet aesthetic and a bit of insulation to the conductive layers. 




For the coding part, I made a one-time code that could be reset manually by using the reset button. First, the code will go for a 40 seconds countdown after the trigger is activated which I think is a reasonable time for you to type the 4-digit code and select the tip amount. If the card is not put back manually and reset by the user. The alarms will go off.




Process (Including ideation drawings, images of the work in progress, and videos of the different steps)

First, I made an idea sketch up on what I would like the prototype to look like.


After the basic sketch-up is done, I started to make hardback support by stacking up wooden popsicle together.


Then, I use felt fabric to be the base canvas for the circuit and draw the circuit layout with a sharpie. Hence connecting everything together.


Moreover, After the second layer of the felt fabric is done. I sewed all the felt fabric along with the CPX with non-conductive threads.


The design was reduced to one card slot due to the short circuit issue, that happened on the first felt trial, to make sure it works I stayed with one card slot instead.


Eventually, the prototype is wrapped in faux leather and sewed together.



Final Project Images (With the wearable being worn!)






Parts List

  1. Conductive threads
  2. Felt
  3. Scissors
  4. Faux leather
  5. Non-conductive thread
  6. CPX
  7. sewing kit
  8. Popsicle sticks
  9. Sharpie



Circuit Diagram:


(Initial idea with 3 card slots)

Reflections & Next Steps :

For the design structure, it could be a more compact and tight fit. Besides, A transparent insulation layer could be placed on top of the CPX as a protective layer. Moreover, Since the prototype carries out a simplistic mission, more card slots could be made maximizing the capability of the CPX can do. For the next steps, I would be working on more sewing techniques to get a better results outcome. Also, I would get custom reset switches instead of relying on the CPX. At last, the most important part is about portability, I would personally fit a 500mAh 3.7 v battery to the CPX so there will be no wires hanging around


Resources & Related Works (cited in APA)


Google. (n.d.). Jacquard by Google – Home. Google. Retrieved April 13, 2022, from

(Simplistic design references and the compatibility with other wearables)


Ekster: Time-saving carry essentials. Ekster® | Trackable, Smart Wallet for Men. (n.d.). Retrieved April 17, 2022, from 

(Overall design references)

Expressive Wearable Assignment – Marcus Tang



Facial expression is one of the most important keys for face to face communication, however being in an environment where masks are mandatorily required would take away one of the features of real life interaction. Some might also find it hard to gain recognition in a group conversation since no one might read the lips of the person initiating speech.


LOAD Mask:


LOAD is a light visual presentation located on the mask. when activated by touching both sides of the conductive materials, it will light up a sequence of blue led light going clockwise for signaling in conversations/etc.  The main emotion for this prototype is that using blue light  would be the most suitable color where in Japan, police use blue streetlight to lower the crime rate. Also, by using slow led sequences to introduce calming sensation.




As schools start getting back to the in person days, it is quite frequent to engage in a large group conversation. As the person that was not preferred to speak voluntarily, there were things that I was aware of in a large group setting. Sometimes there were people who tried to engage in a conversation but were left out because of volume issues and hard to read the lips since masks were mandatory. The mask was to inform surroundings in a calm emotion while letting people know that you are ready to engage/have a point. In addition, this will be considered as an expressive prototype.




First I brainstormed about what I should make and by using randomized three words I drew from three tabs I got “Mask” as the cloth type, “Calm” as the emotion and “Aware” as the actuation. Then I drew an Idea of using circuit playground express as the main source of technology for the lightshow sequence.

Circuit Diagram




Once the design was drawn, I started to do the blue led light sequence animation from MakeCode.


Then I used clamp wires to test the circuit before I started to craft the prototype.


After succeeding the circuit test, I started to craft the prototype by cutting out a used t-shirt as the circuit board. Then the circuit was drawn and sewed with conductive thread. After the thread is well connected then I sewed the CPX secured to the cloth and covered the led with another cut t-shirt. I cut out two little pieces of conductive fabric and placed it on the top layer as the activate switch. Eventually the design was secured on the mask by threads and double sided tapes




Since I couldn’t find a battery in time, I will be using micro usb to demonstrate the work:


Final Project Images


Part list

  • Cloth Mask
  • Circuit Playground Express
  • Conductive Thread
  • Conductive Fabric
  • Double sided tape
  • Needle
  • Wool Thread
  • Scissors
  • Used T-shirt


Reflection and Next step

From this project I can see more potential and the cons of the prototype. The light could be expressed in more ways such as different patterns to indicate different situations and could really use a battery for the portability purpose. 


Also there are flaws from the design that I spotted in the middle of the creation. The clothing is not waterproof at all; any contact of water might get it  to complete the circuit itself without activation. Also, it means that the accessory cannot wear too long since the air vapor produced by nostrils might complete the circuit as well. Because the components are sewed in and taped with electronics, it makes the mask not washable, if I would improve the design I would use Velcro to secure the electronic parts so it could be washable. The prototype will be advised as an accessory means that a surgical mask is required to be worn underneath for Covid protection. 


For the next steps, I would be more aware of the flaws that I spotted throughout the project such as convenience and durability/ maintenance of the product to make it more user friendly. There are things that could be done better such as molding a plastic layer for water resistance. Most importantly is to prepare more time for the project to patch the flaws of prototypes.


Resources and Related work

Shimbun, T. Y. (2008, December 10). Blue streetlights believed to prevent suicides, street crime. The Seattle Times. Retrieved February 21, 2022, from,percent%20in%20blue%2Dilluminated%20neighborhoods. 

(Journal about decreasing crime rate from using blue color streetlight in Japan)


Vega Edge. SOCIAL BODY LAB. (2019, March 1). Retrieved February 17, 2022, from 

(Related work that inspired me, using expression as the main feature and combine practical use of it)