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context - laundromat
problem space

Design a physical or digital control that has a distinct input and associated outcome for an assigned context

my take

I wanted to consider elements of discoverability and design principles while designing the microinteraction


Individual project


MA Design, CMU

process at a glance

The process i followed was a series of diverge and converge steps, going broad in my exploration of all interactions, then narrowing down to focus on one control. Next, I explored multiple design possibilities for that one control. Lastly, I narrowed on one design, and refined it through iterations - closely looking at small details

inventory of interactions

The laundromat is a rich ground for interactions. With change machine, laundry bag dispenser, vending machine, toy game, it goes well beyond allowing one to wash and dry clothes.


I started by making an inventory of interactions that interested me against elements that contribute to discoverability - Affordance, constraints, signifiers, mapping, feedback and conceptual model. To help complete my understanding, for each of these interactions, I noted what worked well and what didn't.

Among the many interactions I observed, the laundry bag dispenser intrigued me the most, mainly because it was the only one that I couldn’t figure out how to operate

Issues – 
• No signifier that slab has to be pushed inhibits understanding operating mechanism
• No error recovery 

chaotic start

While limiting myself to thinking from three design perspectives (using the overlooked, making the machine "differential" to user, and discoverability), I sketched a wide array of solutions, solving different problems, improving different aspects of the interaction and looking at multiple action possibilities for the single machine

After allowing myself to go in many different directions, I narrowed my focus by defining my goal for the design, starting to think in terms of a single interaction rather than as a machine capable of multiple interactions

I decided to concentrate on "putting money and retrieving the laundry bag". I hoped for my design to allow:


  1. User to understand what to do

  2. Ease of operation

  3. Doing more with less

conceptual directions

no push required

single slot for coins

single push

NO PUSH - The existing design involves placing the coins and pushing the slab to get the bag. This direction allowed me to eliminate the number of actions to be performed by removing the need to push

SINGLE SLOT FOR COINS - Current design has 2 separate slot areas for the 2 different type of bags. This direction allowed me to eliminate the need for user to match slot with the bag they wanted to purchase

SINGLE PUSH - Existing design has 2 separate push slabs, one each for the type of bag. This direction allowed me to eliminate that and do more with less

decision making


Decision: While a no push version allows reducing the number of steps performed by user, I decided to go with Push versions

Guiding principles  

Error recovery: Push allowed lower scope for making errors and recovering from them – there is no undo since there is no selection

Minimalism not attained: Would require multiple slots if deliberate selection is to be allowed


Single push button would make it conditional on bags being of different prices. While this would not be a problem at the moment, it could become one if more variants of same price got added in the future

Once I finalised on the "single slot for coins" direction, I then sketched variations of the design to decide the finer details like placement, shape, written instructions and look and feel of the design


AFFORDANCE : Machine is placed on the floor, with the coin slot at an easy reach for the average height of an American woman (5’4”)



  • Colour consistency – Each space where an action is to be taken is marked in blue

  • The placement of the slot, at a height below the eye level of an average American woman suggests where to put the quarters

  • Slight depth signifies the act of “putting things”

  • Touch screen lighting up signifies where to tap



  • Spatial analogies – Screen for a particular quality of bag is placed directly under the photo of that bag

  • Natural grouping of controls – The placement of unused coin collection is grouped with collection of bag - so the user collects either change or bag

  • Analogy between current situation and previous experience – Similar to ATM


CONSTRAINTS: Screen lights up only when enough money has been put for a particular quality of bag -  limits when you interact with a screen and prevents error


FEEDBACK: Auditory and visual feedback at different points allows user to understand the status of the system and their actions

  1. Once user puts 50 cents, first screen lights up. User can tap screen to collect bag
  2. If user puts another quarter, second screen also lights up.
  3. At this point user taps the screen for the bag they want. Even after putting 75 cents, the user can decide on the 50 cent bag. The leftover quarter is returned
  4. The dispenser opens to reveal the bag which the user can pull out (like cash from an ATM) 
key decisions and design principles 


Alternatives: On top (mapping order relative to steps performed) v.s. Below (ATM style)

Decision: Below 

Guiding principle 

Knowledge in the head: Analogies between previous experience and current situation brings familiarity. On testing, I saw that users found it more intuitive than the placement mapping order of steps


Alternatives explored: Circular and rectangular 

Decision – Rectangular, even though circular could have acted as a signifier to put a coin

Guiding principles 

Consistency and standard: wrt rest of the machines in the context

Knowledge in the head: analogies between previous experience and current situation brings familiarity 

**Tested with audience


Alternatives explored: Vertical and horizontal

Decision: Horizontal 

Guiding principle 

Error prevention: Prevents falling of coins even if they slip from the hand, allowing user to freely put coins rather than placing them carefully


Alternatives explored: Screen v.s. Image of bag on push button 

Decision: Screen

Guiding principle 

Minimalist : While the image itself could have acted as a push button, getting lit up, I decided to introduce a screen since it could be used for 
giving different feedback. 
Example - Timer suggesting the transaction is in progress, out of stock message


Alternatives explored: Separate push button v.s. on screen option to cancel

Decision: Separate push button

Guiding principle

Making things understandable: If user has put one quarter only, no screen is lit, making cancellation impossible; if multiple screens are lit, confusion over which to use to cancel



1. Single dispenser - Rather than having 2 separate dispensers mapped to different bags, I decided to keep a single dispenser which would give the bag based on selection.

Guiding principle - As little as possible / minimalist 

2. Putting same picture of bag on screen that is visible on top, so person doesn’t have to remember the mapping and which screen to tap on

Guiding principle - Recognition rather than recall

3. When the screen should light up – only when it becomes actionable. Till then it is dead and doesn’t compete with other choices that may be actionable 

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