HeatCraft: Designing Playful Experiences with Ingestible Sensors via Localized Thermal Stimuli

Zhuying Li
Published in
4 min readApr 15, 2019


This article summarizes a paper authored by Zhuying Li, Yan Wang, Wei Wang, Weikang Chen, Ti Hoang, Stefan Greuter and Florian ‘Floyd’ Mueller. This paper will be presented at the ACM CHI Conference on Human Factors in Computing Systems (CHI), on Wednesday 8th May 2019 at 9:00–10:20 in the session Subconscious Game Controls.

Ingestible sensors are devices that perform sensing functions inside the human body. They have been widely used for medical purposes such as endoscopy, patient monitoring, and medication adherence. However, people might feel uncomfortable about swallowing such a sensor. This study explores the opportunity of designing playful experiences around ingestible sensors to improve the overall user experiences.


We present a novel two-player system called HeatCraft. We conducted a user study with 8 pairs of participants to understand the associated user experience. Participants were required to swallow an ingestible sensor that measures their body temperature as it travels through the gastrointestinal (GI) tract. A waist belt equipped with heating pads that generates thermal stimuli was worn by the participants. The intensity of the stimuli was based on the participant’s body temperature. After the set-up, participants were allowed to go back to their daily routine and freely explore the affordance of the system. After the players excreted the sensor, they shared their experiences with HeatCraft with us. Based on this, we propose eight design strategies for designing playful experiences around ingestible sensors.


Overall, HeatCraft was intriguing and playful. It facilitated ubiquitous playful experiences, augmented the participants’ bodily experiences and promoted awareness of their own body and how their body reacts to the environments they are travelling through. We analysed the interview data and derived three themes.

· Integration of Body and Technology

Ingestible sensors were inside the participants’ body and other parts of the system were made as wearables. This intimacy between HeatCraft and the participants’ body influenced their bodily experiences. For example, the system increased the participants’ bodily awareness by directing their attention inwards.

· Integration of Internal Body and Outside World

The surrounding environment (e.g. the environment temperature) and the participants’ actions such as eating and exercising could influence their body temperature, which would be revealed by the system via the thermal stimuli. Therefore, HeatCraft made the participants become more aware of their daily actions and environment. This could help them treat their bodies better in the future.

· Integration of Play and Life

HeatCraft facilitated ubiquitous playful experiences since the system did not interrupt the participants’ daily lives. For example, a participant reported: “The system turns daily activities to potential game actions and turns all the objects around me into game resources.

We also propose eight design strategies for designing playful experiences around ingestible sensors. For example, considering that players appreciated that HeatCraft reminded them of body temperature anywhere and anytime unobtrusively, we recommend designers to facilitate implicit interactions which do not require the user’s explicit awareness in ingestible play. Moreover, players appreciated the experience of having an ingestible sensor entering their body and guessing when the sensor would come out. Therefore, we recommend designers to highlight the experience of ingesting and excreting the ingestible sensor when designing ingestible play. More broadly, “crossing of the body boundaries” can be a design element to facilitate a playful experience.


We believe that this work’s findings can be useful for a range of different fields including medical science, electrical engineering, design and HCI. Medical practitioners could realize the importance of patients’ first-person experiences and create better experiences around ingestible sensors. Engineers who develop ingestible sensors could provide SDKs for others to use the devices in non-clinical contexts. Designers and HCI researchers could be inspired to consider ingestible sensors as a design resource, especially for facilitating playful interactions. Moreover, we open up new possibilities to help designers facilitate the integration of body and technology to blur the boundary between play and life.

For more details, please read our paper and see our presentation at CHI 2019. You can also follow this project on the blog.

Full citation: Zhuying Li, Yan Wang, Wei Wang, Weikang Chen, Ti Hoang, Stefan Greuter, Florian ‘Floyd’ Mueller. 2019. HeatCraft: Designing Playful Experiences with Ingestible Sensors via Localized Thermal Stimuli. In CHI Conference on Human Factors in Computing Systems Proceedings (CHI 2019), May 4–9, 2019, Glasgow, Scotland UK. ACM, New York, NY, USA, 12 pages. https://doi.org/10.1145/3290605.3300806



Zhuying Li

Ph.D. Student at Exertion Games Lab, RMIT University