“Scents of Smell” is an interactive prototype we created as a 3-people team to allow users to test their senses of smell without necessarily having to see all of the mechanisms behind the scenes – though they still can if they wish. With just the press of a button, a random scent will be emitted from the house-shaped prototype for players to guess what the scent is, and a flash of light will automatically provide feedback on whether or not the guess was right or wrong. With “Scents of Smell,” we hope that people of all ages can have a simpler, more technologically advanced, and funner device to test their senses of smell with.
Initial stage: research and ideation
There is still much to learn about the brain and its functionalities, but recent research suggests that sensory inputs and sensory processing, or the way in which the brain registers, interprets, and uses information from the sensory systems, play important roles in improving neural circuitry. And while it has often been believed that humans’ olfactory system is generally less significant than the other sensory systems, studies have now proven that the cortical areas of integration of the olfactory sensations have important interconnections with language and memory and significantly impact humans’ behaviors and interpersonal relationships. It may be also interesting to note that children who are unable to distinguish between pleasant scents and repulsive odors are more likely to be diagnosed with autism, perhaps as an indication of their later social difficulties. And yet, despite all this, not many interactive pastimes revolved around enhancing or testing people’s senses of smell exist. A quick Google search shows that many smelling games are for pets – just dogs, really – and those not for pets are either not particularly technologically enhanced with bottles and cotton laying everywhere or too much so in their incorporation into role-playing virtual reality games. Realizing this shortcoming, we decided to create a prototype, called “Scents of Smell."
The low fidelity prototype is displayed above. For the water atomizers, we cut off the bottoms of water bottles and used them to represent the plastic containers, toilet paper to represent the cotton swab that will connect the water-soluble scents to the ultrasonic transducers, the bottle caps to represent the ultrasonic transducers, and the strip of plastic under the bottle caps to represent the cables connecting each ultrasonic transducer to a separate driver board. We then used another plastic wire to indicate the connection that the driver boards will have with the Arduino board, as well as an actual cardboard container that can be fixated over the entire prototype to cover the system and allow the emission of the scents through an opening at the top. We also attached one of the paper windmills from our initial prototype onto the back of the container so that it can blow the scents towards the user. We explain more about our this prototype in this video:
High Fidelity Prototype
Scents of Smell has five main features, or five functional blocks: the set of water atomizers that will diffuse the eight scents available, the keypad that will obtain the input for the system from the users, the LED lights that will display the output to the users, the container covering all of the mechanisms, and a box of coffee grounds that are slightly separate from the actual system to help users neutralize the scents already emitted.
Water Atomizers: Heart of System
The water atomizers are the first functional block and are the heart of the system, providing the basis for the two modes we have available in our prototype: the Normal Mode and the Game Mode. We have a total of eight water atomizers, each of which emits a different scent – Mandarin Rose, Clean Rain, Tea Tree Mint, Sandalwood, Eucalyptus Spearmint, Vanilla, Japanese Cherry Blossom, and Ocean – and each of which contains three fundamental hardware components – a driver board, an ultrasonic transducer, and a cable to connect the two. The Grover interface on each driver board is attached to the main Arduino control board with a wire while each ultrasonic transducer is further e attached to a cotton swab soaked in one of the eight water-soluble scents. In order to control the ultrasonic transduction process, we connected all eight atomizers to different pins on the Arduino board so that the atomizers can be directly linked to a computer and thus operate mainly on electricity.
During the process of connecting all the parts, we encountered difficulty attaching the ultrasonic transducers to the containers we used to store the water-soluble scents in because the opening of the container was slightly smaller than the ultrasonic transducer. To address this issue, we measured the diameter of the ultrasonic transducer and the width of the container and then 3D-printed a cap for each container to stabilize the ultrasonic transducer, making sure each ultrasonic transducer is appropriately in contact with the damp cotton swab inside the container. Additionally, we wanted all of the scent containers to be placed properly and firmly so we laser-cut a placeholder for the scent containers by making two rows and placing four of them in a row.
Keypad: Input of System
The keypad is the second functional block and is the primary way users can directly interact with Scents of Smell. We used the 4x4 keypad that has number keys “0-9,” letter keys “A-D,” and special keys “*” and “#.” We imported the corresponding built-in Keypad library designated for Arduino boards so that the keypad and Arduino board would be connected and work in tandem as a means of communication and control in the system. On the keypad, the numbers “1-8” each correspond to one of the eight scents – “1” corresponds to Mandarin Rose, “2” corresponds to Clean Rain, “3” corresponds to Tea Tree Mint, “4” corresponds to Sandalwood, “5” corresponds to Eucalyptus Spearmint, “6” corresponds to Vanilla, “7” corresponds to Japanese Cherry Blossom, and “8” corresponds to Ocean.
LED lights: Output of System
The LED lights are the third functional block and are the primary way users obtain feedback from Scents of Smell when participating in the Game Mode. Specifically, one of the three LED lights turns on immediately after the users have used the keypad to input their guesses of which scents were among the mixture emitted at the start of the Game Mode. Depending on how many scents the user guesses correctly, a different color LED will light up to indicate proper feedback. Like the keypad, the LED lights are connected to the Arduino board and controlled via Arduino code.
Container: Aesthetics of Prototype Design
The container covering the whole prototype is the main change we made to the initial prototype. For both aesthetic and disguising of the scents purposes, we designed a Christmas-themed house to cover the water atomizers, breadboard, Arduino board and all the wires, and two holes on the roof letting the scents come out. We started by drawing a house in Adobe Illustrator, and then laser-cut the pieces and constructed the house by hands. In order to make the house more visually appealing, we painted the house red and the roof black, aligned the roof with cotton to build a winter-like environment, and decorated the roof with our prototype name, “Scents of Smell” using white flakes. Inside the house, we also laser-cut another piece of acrylic constructing a another layer or floor of the house to better arrange everything by placing all the wires, breadboard and the Arduino board on the first floor, and all the scents containers and the placeholder on the second floor.
In addition, we laser-cut a small cube container for the coffee grounds and decorated it with a small green plant made by paper.
Coffee Grounds: Separate from System
The aforementioned coffee grounds are the fourth and last feature of Scents of Smell. Unlike the former functional blocks, however, the coffee grounds are not directly connected to the Arduino board or controlled via Arduino code. Rather, the coffee grounds are placed in a laser-cut acrylic container that can be passed around to any user who may want to neutralize the odors in between smelling each scent in the Normal Mode or before playing a game in the Game Mode.