Angry Bag


Angry Bag

Priya Bandodkar



Emotion: Anger

Actuators: LED Light, Servo Motor

‘Angry Bag’ is a bag that doesn’t like being overloaded. If overburdened, it blinks a warning. If not acted upon in time, it gets aggravated and opens the bottom flap, dumping all the things inside it onto the ground.

The bag is installed with a circuit enabled by an analog pressure sensor on the bottom flap. When loaded beyond its threshold, the analog switch senses and turns on the circuit, making the LED blink as an indication (State one). If the user fails to act and reduce the weight within a specified timeframe, the servo motor holding the bottom flap rotates to open the flap (State two), thus dumping everything in the bag onto the floor.

The entire bag is designed from scratch and built by laser-cutting and assembling Birch Plywood for the prototype. The use of wood lent a clean, sturdy and appealing form to the bag. The choice of building from scratch helped avoid the technical and aesthetic restrictions that came about from augmenting an existing bag.



02 03 04 05



I invested relatively more time in planning the design and functionality during the ideation phase because of the following reasons:

  • Every part of the of the circuit was going to be on a different side of the bag: Adafruit CPX board on the inside of the back, servo motor on the outside of the back, LED on the outside of the front and analog switch on the inside of the bottom flap. All of them needed to function in tandem without interfering with each other.
  • Since this piece was small in size as compared to the parts it had to carry, the available real estate had to be well-used.
  • The bag was designed from scratch and would be laser cut, hence the design needed to be as precise as possible during ideation to avoid wastage of material.


Physical Design

Body Material: ¼” Birch Plywood

Fabrication method: Laser-cutting

Sling Material: Metal sling

02_laser-cut-diagram 03_laser-cut

Since all circuit parts were on different sides of the bag, having a sturdy outer form was crucial to maintain the integrity of the circuit and the overall functionality. Hence, the choice of a hard geometric form built from scratch. The flaps were connected to the sides using hinges, so they could rotate smoothly to open. This overall design choice also helped avoid technical and aesthetic restrictions that would’ve come about from augmenting an existing bag.

Technical Design

The working of the servo motor was crucial to the overall functionality of the wearable. I realised there were two potential ways of using the servo motor to open the bottom flap:

  1. Attaching it the side edge of the flap to control the motion.
  2. Using it as a latch, which on rotation would release the flap to open under the influence of gravity.

I went for the latter one because I think it was wiser putting gravity to work, instead of leaving the pressure on the servo to drive the motion along with and against gravity.

I started by assembling the front, sides (using glue) and bottom flap (using a hinge), leaving the back open till the entire functioning was well-tested. I then secured the analog switch on the bottom flap, the Adafruit CPX on the inside of the back, servo on the outside of the back using double-sided tape and glue. I covered the bottom analog sensor with a yellow felt, and secured all ends of the wires with insulation tape.


Throughout the ideation, my biggest worry was not knowing the capacity of the servo motor to sustain the weight of the entire form. This was the most uncertain part of the logistics. I had to be mindful to keep the bag weight to its optimal. I realised that the bag looked like a ‘bag’ with or without the top flap. Since it was no more a crucial aspect of the aesthetics, I decided to let go of the top flap, thus reducing the overall weight. To my relief, the setup worked and the servo motor worked perfectly.


The code simply uses data from the analog sensor on the bottom flap, which is triggered by the weight of the objects inside the bag. The analog threshold makes the LED to start blinking. Each LED blink is linked to a counter. Thus once the counter reaches a specified count, the servo motor rotates and sets the bottom flap to open.


I had a geometric, boxy form in mind for this wearable from the very beginning. I believed it was important in order to bring out the two states expressing the emotion distinctly. I consciously didn’t want the emotion to be lost because of the form. This choice proved just right for the purpose. Also, lent a clean look to the wearable. On the front side, I purposefully engraved a geometric pattern that resembled the shape of eyebrows when angry, thus accentuating the emotion through the design. I placed the LED above this, in the centre (trying to represent hot-headed/also the third angry eye belief prominent in Indian mythology). The servo motor was hidden on the read end, and circuit was hidden within the bag, thus creating a clean-looking, contemporary electronic wearable.



Part Source
Adafruit Circuit Playground Express Board Creatron Inc
LED Light Creatron Inc
Servo Motor Creatron Inc
Analog Sensor (Velostat, Conductive Fabric, Neoprene) Re-used materials provided by Kate during class
Wires, Resistor Creatron Inc
Birch Plywood Ground Floor, 100 McCaul
Metal Sling Re-used from a worn out bag





Since the beginning of class, I had an inclination for concepts that involved designing an electronic wearable bag entirely from scratch or augmenting existing bags, be it handbags or backpacks. This so, because personally, I have a tendency of overloading my handbags and backpacks, without being mindful of the weight, eventually wearing them out faster and totally straining my shoulders and back. Below are some of the other ideas I had devised while brainstorming for the ‘Textile Interface Project’, which revolved around bags.


I found inventions in the realm of electronic wearable bags, particularly luggage bags that proposed ‘smart’ design solutions. For example, suitcases like the Incase ProConnected ( or the Genius Packed Supercharged ( provide charging solutions while on-the-go.

Image sources:

Another very intriguing design solution that innovatively address luggage weight was the Modobag (, the first-of-its kind motorised carry-on travel bag, that could double as a motor scooter using a built-in seat and footrest, helping you navigate through the airport without having to walk. A solution for travellers who would rather sit and steer as they make their way through the airport and go through the long lines. The scooter is capable of delivering at a speed of 8 miles per hour, and can go about 6 miles on a single charge. Whether ridden or dragged, it has two USB ports to keep devices charged. Moreover, it has an optional GPS system to keep track of the Modobag itself. However, the bag weighs a hefty 10 pounds when empty, thus leading to inconvenience when not being ridden. This got me more mindful about keeping a check on the weight while building the Angry Bag.

Image source:

Another design solution that was a closer reference to the weight aspect of my exploration was the self-weighing bag by the British Company, Expert Verdict, that had an LCD display below the handle depicting the weight of the contents in the bag (

A cutting-edge wearable bag project that sparked my attention was the “Smart handbag as a public wearable display”, which was a smart bag that had a display screen which could be accessed using the phone. The bag screen had six different visualization styles to show the content items in various degrees of detail. The main versatility of this project, in my opinion, lied in the affordance this screen offered, from displaying contents present inside the bag to using it to  matching the handbag to other surfaces on which it is placed, or to match the day’s attire. This was referenced as the chameleon effect.

Image source:

Synthesising these inspirations, I thought this project was a great opportunity to not only assess the weight of the contents and make the bag ‘smart’ but also add a unique perspective by making the bag ‘emotional’. Using a sequential process of blinking an LED and a rotating servo using a counter in the code that worked as a stopwatch, I was able to lend a personality to a boxy form. And thus evolved ‘Angry Bag’.


  • Use textile mediums for connections such as conductive fibre or fabric, instead of wires to making the circuit cleaner, more ‘invisible’.
  • Create the final model using semi-transparent acrylic to show off the electrical assembly, as opposed to hiding it and accentuate the bag’s personality of being an ‘emotional electronic’.


Coomes, Kailla. “Bags with Brains: Smart Luggage and Gadgets Are Making Travel Smoother.” Digital Trends, Digital Trends, 18 Mar. 2019,

“ProConnected.” Incase Canada,

Genius Pack. “Extremely Functional Luggage, Innovative Travel Products.” Genius Pack,

“Modobag® – The World’s ONLY Motorized, Smart, Connected Carry-on Luggage!” Modobag,

Martin, Rick. “Self-Weighing Suitcase Knows Exactly How Heavy It Is.” New Atlas, 2 May 2015,

Colley, Ashley & Pakanen, Minna & Koskinen, Saara & Mikkonen, Kirsi & Häkkilä, Jonna. Smart Handbag as a Wearable Public Display – Exploring Concepts and User Perceptions, 2016, 10.1145/2875194.2875212.

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