key: cord-0204065-o093bcxb authors: Shandilya, Esha; Wang, Yiwen; Zhao, Xuan; Fan, Mingming title: EvoK: Connecting loved ones through Heart Rate sharing date: 2021-02-21 journal: nan DOI: nan sha: 74c2fa5e6d6f79618cb456de95ca268789a7af51 doc_id: 204065 cord_uid: o093bcxb In this work, we present EvoK, a new way of sharing one's heart rate with feedback from their close contacts to alleviate social isolation and loneliness. EvoK consists of a pair of wearable prototype devices (i.e., sender and receiver). The sender is designed as a headband enabling continuous sensing of heart rate with aesthetic designs to maximize social acceptance. The receiver is designed as a wristwatch enabling unobtrusive receiving of the loved one's continuous heart rate with multi-modal notification systems. This has motivated researchers to design different form factors to sense and share heart rates. For example, Werner et al. [17] designed a ring that can detect the wearer's heart rate and send it to the partner's ring via vibration feedback. However, participants felt the vibration feedback as a feeling of "electric shock" and was elusive to infer the corresponding heart rate. Croft and Lotan [8] created a device named imPulse with a curved surface so that users could put it on their laps and palms on the surface, providing synchronizing light and vibration feedback. However, imPulse is nonwearable, which makes it immobile and unusable when a user is performing other activities. Min and Nam designed WearBEAT to share body sound including the sounds of heartbeat [10] . In their design, one user wore the sound input part on the chest mount to sense the heart rate, and the other user received vibration feedback on their wrist as output. However, the chest-mounted prototype violates the parameters of Zeagler's [19] body map locations for wearable; since the position near breast could be uncomfortable for wearers especially for non-male users, which might affect its social-acceptability. Inspired by these designs, in this work, we explore a different form factor to sense and share one's heart rate with the aim of increasing its comfort level and social-acceptability. We adopt PPG sensing to detect heart rate as it has been demonstrated to be a promising wearable heart rate sensing approach [2] . Through the combination of headband and wristwatch, we strive to provide a comfortable wearing experience and an intuitive interaction. We followed an iterative design process to finalize the key design considerations for our wearable devices. The design considerations were based on -i) trade-offs between the comfort level and the detection accuracy of the heart rate sensor, ii) ambient notification, iii) socially-acceptable designs. Trade-offs between the Comfort Level and the Detection Accuracy of the Heart Rate Sensor: Before concluding the sensor's placement, we tested various feasible locations, specifically the finger-tip and the ear-lobe, to wear the heart rate sensor to get accurate heart rate. We observed that the finger-tip position added noise to the heart rate due to hand-movements, whereas the sensor's placement on the ear-lobe reduced noise in the recorded heart rate. Consequently, we decided to use the ear-lobe for the sensor's placement. However, the batteries' weight pulls the sensor down when placed on the earlobe, impacting the wearer's comfort and the sensor's accuracy. To overcome this challenge, we brainstormed a solution that could support the batteries' weight to keep the heart rate sensor's position intact on the ear lobe, providing a seamless experience to the wearer. We deliberated the feasibility of multiple design alternatives such as earrings, neckwear, hair clips, and headbands. The headband prototype, Figures 2, offers the best weight distribution of the batteries than the competing alternatives; the encased batteries are attached to the headband, which rests on the head, providing stable heart rate sensor positioning. Ambient Notification: The next design consideration was to design an unobtrusive notification, which the wearer can easily follow without getting overwhelmed with the constant influx of the sender's heart rate. According to Hansson and Ljungstrand [4] colored LED lights are less intrusive methods of notification systems than other forms such as sound. Therefore, we devised three different LED lights to indicate the heart rate range; considering that the normal heart rate range is between 60 to 100 for an adult, according to Mayo Clinic [6] . In the Figures 4, we see the blue light for heart rate less than 60, the green light for the heart rate between 60 and 100, and red to highlight the heart rate beyond 100. In case there is a constant high heart rate of the sender (beyond 100), the receiver (wearer) will be alerted by a high pitched sound. Moreover, we also provide an option for the user to control the sender's heart rate transmission by pressing a button on the receiver's prototype. We abandoned the idea of incorporating haptic feedback to the prototypes, as it may be intrusive and dysfunctional for users to interact with the prototype. Socially-acceptable Designs: Social acceptability of a wearable device directly depends on its placement on the user's body [19] . Our wearable designs are conceptualized according to the socially-acceptable body locations suggested by Zeagler [19] that provide comfort and confidence to the wearer in public. Therefore, after referring to the body map [19] , we chose the two areas -the head and the wrist that offer comparatively better affordance for the device placement, and thus we select the form-factors of a headband for the sender and a wrist-watch for a receiver. Such form-factors, (headband and wrist-watch), Figures 2 and 3 , are intuitive, user-friendly and easy to interact with as these are familiar form-factors to the users. We carefully determined these designs as these are gender-neutral and to the most extent used by many. However, we did not conduct user research to assess the designs' social acceptance. Fig. 1 . This is the final stage, where we work to consolidate all the sensors in a usable and functional wearable design. Here the heart rate sensor is a headband design for the sender and when heart rate will be sensed from a specific range then, the data will be shared in the form of visuals with music to the receiver which is in the form of a wrist watch. For different heart ranges, there are specific notifications, please refer Figure 4 for full explanation on design notifications. Our system consists of two parts, the sender and the receiver. The sender's heart rate will be detected and sent to the receiver, and the receiver will get different visual and audio notifications according to the received heart rate value. To conceptualize the sender part, we used a pulse rate sensor to detect the heart rate. The pulse rate sensor was connected to the micro: bit and the code for calculating the heart rate was downloaded to the micro: bit. The pulse rate sensor could be placed on the fingertip or earlobe. We tested both these two placements and found that placing the sensor on the earlobe gave us more stable signals. Also, considering the convenience of a user wearing the wearable device, the sensor should be intact while working out, performing some activity, and resting state. Thus, we decided to put the sensor on the earlobe. We tried to put the sensor on the earlobe and connected it to the micro: bit. We found that the gravity of the micro: bit would exert a great downward force on the earlobe, which could cause ear discomfort. We needed to put the micro: bit in a supportive position. Our initial idea was to put it in the cloth pocket; however, not all tops had pockets. Then we turned to body parts and found the head would be a good choice to put the micro: bit on. We wanted to make our device portable and could be used by anyone. The idea of the hairpin was abandoned because it did not apply to people with short hair. Our idea was to attach the micro: bit to a headband Figure 2 . To compact the battery and connector, we used the 3D printer to print a small box so that all components can get packed in one Figure 2 . When the sender uses this device, they need to put the headband on and place the pulse rate sensor on the earlobe, as shown in the Figure 1 . After wearing the device, it needs to collect one or two minutes of data before getting the wearer's normal heart rate. For the receiver part, we designed some feedback and interactions for the receiver. The receiver also needed to wear the micro: bit to receive the data from the sender. To make it easier to see the heart rate value and feedback, we made the device in the form of a wristwatch. We purchased a somatosensory control development board with a wrist band, an RGB led light, a buzzer, and a speaker, Figure 3 . The micro: bit was connected to the board Figure 3 . We tried to utilize the buzzer to provide haptic feedback; however, the micro: bit was not powerful enough to implement real-time haptic feedback and caused long delays. In our design, we only used the led light and speaker to provide visual and audible feedback, the description can be seen in Figure 4 . When the sender's heart rate was below the normal range [6] , which was less than 60 per minute, the light would be blue. When the heart rate value was in the normal range between 60 and 100, the light would be green. When the heart rate was beyond the normal range, which meant over 100 per minute, the light would turn red, accompanied by a beep sound. The normal range of 60 to 100 was only used for our test. Users could set their own heart rate normal range. Additionally, to provide more flexibility, the receiver could control whether to receive the data or not. They could press the left button on the micro: bit to stop receiving the data and feedback and press the left button again to resume receiving the data and feedback. We present novel prototype designs with feedback for sharing heart rates to alleviate people's social isolation from their loved ones. This work presents a demonstration with a pair of wearable devices that mainly use micro:bit processor and a heart rate sensor. We exclusively made our designs wearable to ensure continuous connectivity through heart rate sharing and indicating the user's physical and mental well-being. Future work should investigate users' attitudes and perception towards the proposed way of sensing and sharing heart rates and elicit feedback to further improve its comfort level and social acceptability. Moreover, it is worth conducting a long-term in-the-wild study to reveal both technical issues, such as battery life, and practical issues emerging from a wide range of daily scenarios. Lastly, as heart rate patterns may vary from person to person and can 4 . Three ranges of heart rate with corresponding feedback: Blue LED represents less than 60. Green LED represents the normal range between 60 and 100. Red LED and alarming sound represents over 100. According to Mayo Clinic [6] , the normal resting heart rate of an individual ranges between 60 and 100; other factors such as, age, fitness level, emotions could also influence the heart rate. The heartbeat value of the sender is displayed on the Microbit's screen. Note: The heart rates displayed are two and three digit numbers. One single digit is shown at a time, and the digits are moving from right to left. The first value on the receiver's device is the first digit 3 of 30 with a blue LED light, second value is 5, the last digit of value 65 with green LED light, and the last value is 1, the first digit of 130 with red LED light. carry important health-or emotion-related information, it is worth exploring the characteristics of such patterns and designing prototypes to capture and communicate them among loved ones. Emotional loneliness and coping strategies: A reference to older Malaysians at nursing homes Heart rate monitoring as an easy way to increase engagement in human-agent interaction Breeze: Sharing biofeedback through wearable technologies The reminder bracelet: subtle notification cues for mobile devices Loneliness matters: A theoretical and empirical review of consequences and mechanisms What's a normal resting heart rate? 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