The Ambient Holodeck Multisensory System Design
Since the early days of the Star Trek Holodeck, researchers and designers have been intrigued by the value of recreating the physical world in multi-sensory realism, using the five primary senses, sight, sound, touch, smell, and taste.
The goal of the Ambient Holodeck was to replicate environmental conditions of two stream habitats. We use this system to compare how learners make observations and infer patterns, with and without ambient sensory cues (smell, heat, humidity, wind). We used this system to test the effectiveness of multisensory cues on stimuli in VR.
Environment Space Design
My goal was to allow participants to rotate freely in a 360 degree spherical video. It was important for participants to experience the directional Multisensory components from different angles, and to extend their arms in order to point and gesture.
Design Process: My first design placed sensory components on a desk in front of participants, however I found that they were too small and far away to create realism. My second design attached a removable tray to a full back swivel office chair, and placed sensory components on this tray. The tray was constructed from foam-core and was held onto the chair with Velcro. This light and sturdy design allowed users to freely turn the chair around to explore the space in VR. The chair was easy to assemble, but required participants to have their hands confined to the armrests in order to not tip over the equipment. Further, equipment was mounted to the front of the chair, so participants could not feel the ambient sensory information behind them.
Final Design: My final design placed sensory components around the study space, integrating the olfactory, humidity, thermal, wind, and ergonomic designs. Study participants were seated in the middle of the multisensory space on a backless swiveling office chair. Participants felt environmental warmth from the two mounted heat lamps, and felt hot and cool humidity from the cool mist humidifier and the steam vaporizer. In complement to this, participants felt breeze through two portable fans. Finally, participants smelled the environment through an olfactory mechanism I developed using radial blower fans.
The goal of the thermal system was to realistically replicate directional and ambient heat from the sun.
Challenges: I encountered two challenges in recreating ambient heat. The first challenge was to find a powerful and safe directional heat source. A second challenge was to find a powerful heat source that could quickly heat the study space.
Design Process: I considered several heat sources during my design process. First, I tested small and large personal space heaters. The small heater provided reasonable heat up to two feet from the participant, but it became ineffective when it was placed any further. Likewise, the large space heater took upwards of 20 minutes to heat the room appreciably, rendering it ineffective for my purpose. My second design mounted hair dryers on poles pointed towards the center of the study space to provide directional and ambient heat. The hair dryers were effective, but they generated considerable wind and noise that could be heard through the VR headset.
Final Design: My final design used two Philips 250W incandescent heat lamps mounted in reptile lamp stands. I configured these lamps to the direction of the sun in my 360 degree videos; one lamp simulated the sun, while the other provided ambient heat. The first video was of a sandy open environment. To simulate this habitat, both lamps were switched on, providing the participant with directional heat from the sun and ambient environmental heat. The second video was of a shady forested habitat. For this video, only the overhead heat lamp was used to provide ambient heat.
It was important to realistically simulate the evaporated moisture created by diverse stream habitats. In the first video, I needed to replicate the humidity of a hot spring, and in the second video, I needed to replicate the cooler ambient humidity of a redwood forest stream.
Challenges: I encountered three challenges in generating ambient humidity. One challenge was to generate enough water vapor to simulate humidity. A second was to distinguish warm humidity from a cooler mist. A third challenge was to make the humidity feel directional, as though it was coming up from a stream.
Design Process: I considered different humidifiers and placements during design. The first design using two portable Cingk personal cooling misting fans, placed by participants' hands and feet. I found that by themselves, the misting fans were too small to generate ambient humidity. Further, fans had to be placed next to the participants, and were prone to being knocked over. In my second design, I placed a Vicks Pediatric Steam Vaporizer on the floor. The vaporizer generated steam, simulating the hot spring in the first habitat. However, the vaporizer was uncomfortably hot when placed close to participants' feet, and could not provide the cool mist I required for the redwood habitat.
Final Design: My final design combined the vaporizer with a Walgreens Cool Mist Room Humidifier. The hot vaporizer and cool humidifier were angled toward each other, approximately two feet from participants. Combined, the humidifier provided participants with a strong directional mist, while the vaporizer generated ambient steam around the study space. In the first video, both the vaporizer and humidifier were switched on, mixing hot and cold mist. In second video, only the cool humidifier was switched on, simulating directional mist rising up from the forest stream.
I wanted users to experience environmental "smellscapes.'' It was important for olfactory elements to be distinguishable from one another so that they genuinely represented the kind of conditions that participants would experience at the different habitats, and distinguish them from the study space.
Challenges: One design challenge was to dissipate environmental smells between studies quickly without bulky equipment. Another challenge was to make the olfactory experience ambient without seeming artificial or directional.
Design Process: First, I designed a rotating wheel mounted onto an Oculus head-mounted display (HMD) with cotton pads next to the participants' nose. This system was passive and expected users to take deep breaths. I abandoned this system because the powerful scents made pilot participants uncomfortable, and weighed down the headset. My second prototype used a desktop fan to blow air towards the participant through cotton pads charged with essential oils. This design was ambient and more comfortable, but created appreciable wind that overpowered the fans I was using to simulate wind.
Final Design: The final design used three 5v 5015 cooling blower fans mounted with their exhausts facing the participant. Two cotton pads charged with scents were placed on the intake sides of two fans using a 3d printed mount. A third fan blew fresh air towards the participant to remove lingering scents. The fans were powered by a 5v power supply, and were connected to 3 push button switches. During the study, the researcher switched the fans on for a few seconds at a time. Between studies, lingering scents were cleared using a floor fan and fume extractor. The fan pushed the scented air across the study space into the fume extractor.
My goal was to generate wind that felt realistic to participants. In the redwood habitat, I needed to simulate a gentle cool breeze.
Challenges: My biggest challenge was finding a source of wind that did not feel artificial and did not drown out the VR audio.
Design Process: I tested different size fans to simulate the breezy forest in the second video. First, I tested an oscillating floor fan, but found that it was too strong and loud to simulate a gentle breeze, and was immediately recognizable as a fan. Then, I tested two battery-powered Cingk personal fans at different speed settings in different configurations around the study space.
Final Design: The final design used the personal fans on their lowest speed, facing the participant from opposing directions. From a few feet away, the fans provided unobtrusive ambient wind that was not immediately recognizable as a fan. Further, the fans' portability allowed them to be easily hidden between studies.