Salinity Sharpie

A multifunctional salinity meter designed for industrial kitchen chefs

#ux-research #product-design




Class Project


Chia-Jung Kuo

Charlene Lu

Katherine Liu

Stephanie He




My Contribution

UX research

User interview, on-site observation

Product design

Sketching, prototyping


Professional chef reusing leftovers

In February 2024, I visited to International House, the biggest residence house at UC Berkeley, which hosts hundreds of international students and events.

Together with fellow students, I had an in-depth conversation with the Sous Chef Aarash and a close in-site observation of the bustling kitchen.


What are their needs?

  1. Leftover Flavor Consistency

We learned that the kitchen team tries to repurpose leftovers to minimize waste and maximize efficiency. For example, they would use sausage and potatoes from previous meals to prepare stew soup. However, due to changes in salt and water levels in leftovers over time, these fluctuations can result in inconsistencies in taste, which is problematic in a professional setting where consistency and flavor are paramount.

  1. Communication between shifts

A common day of the cooking team is busy with teams shifts and lots of overlapping in schedule. Communication to share information about ongoing dishes, including any adjustments made to seasoning or ingredient quantities, across shifts is crucial for maintaining kitchen efficiency and consistency. The best workflow for our design should be streamlined, time-efficient, and easily integrated into their existing routines. This could involve incorporating features such as labeling capabilities or digital interfaces for recording and sharing food condistions, ensuring that important information is communicated effectively and consistently.

Labels as the current way of communication of food in the kitchen

  1. Discretion in technology use

During the interview, we observed that professional cooks prefer tools that are intuitive and unobtrusive, particularly in environments where cooking experience is much valued over reliance on technology. They expressed a desire for solutions that seamlessly integrate into their existing workflows without disrupting the natural rhythm of the kitchen.

So our design needs to prioritize discretion in technology use, providing functionality without unnecessary complexity or reliance on advanced features. This includes focusing on simplicity in both form and function, with a design that is familiar and easy to use for cooks of all experience levels.

A pocket thermometer currently used by the chef

A pocket thermometer currently used by the chef

How might we

Build a tool that better informs the chefs of the flavor change in leftovers, while providing clear communication between team shifts and remaining unobtrusive to professional cooks' reliance on experience?


A multi-purpose salinity sharpie

Based on these insights, we came up with the idea of a salinity tester, combined with a label printer and a sharpie. Its multi-purpose design would allow chefs to quickly measure and adjust the salt levels of repurposed leftovers while seamlessly communicating important information between shifts.

Story board

Physical prototype

For the physical prototype, we built an Arduino circuit to measure the resistance between two electrodes, through which we can know the salinity of the test liquid, and an LCD board to visualize the result. The user would also be able to print a sticky label with the thermal printer inside of the tool, where the user can write down key info about the food conditions.

Label Interface

Demo video