During the last years and especially in the last year, due to the Covid 19 pandemic, it became central the role of digital communication into our lives. However, for people affected by upper limb impairment having an easy and comfortable access to digital devices can be challenging. This thesis illustrates the development of a successful implementation of an assistive device aimed at enhancing the digital life of people with upper limb impairment through the functionalization of their tongue, organ which usually results unaffected from Spinal Cord Injury or Stroke. In the Wearable Technology and Sensory Enhancement (WTSE) Laboratory in Chicago we developed a device featuring capacitive sensors, the Tongue Trackpad (TT), which is inserted in the oral cavity and acts as a trackpad controlled through the tip of the tongue. The device enables a discrete way of interacting with a digital interface for people with disability: it’s indeed inserted in the mouth, therefore limiting the stigmatization of the user. The detection of a touch signal works by self-capacitance, meaning that a scanning signal is sequentially applied to the columns and rows of the Tongue Trackpad and the correspondent change in voltage is measured to obtain changes in the sensors capacitance, which happen if a touch is present. Our device is liquids tolerant: while a scanning signal is applied to one sensor, a shield signal is applied to all the others thus reducing the false touch signals otherwise induced by the presence of saliva in the mouth environment. The Tongue Trackpad can be linked to any digital device supporting the Human Interface Device (HID) protocol, therefore it can be employed to control any smartphone, computer or tablet either iOS or Android because it’s recognized as a Bluetooth Mouse. I developed a first iteration of the Tongue Trackpad inside of the Wearable Technology and Sensory Enhancement Laboratory (WTSE Lab) in Chicago for the Master Thesis at the University of Illinois at Chicago (UIC). The device was realized in three versions: a 5x5, a 7x5 and a 8x7 matrices of capacitive sensors printed on a copper sheet, whose traces are inserted into Zero Insertion Force (ZIF) connectors which carry the signals to a PSoC micontroller (Cypress Semiconductor Corporation). For the Thesis Magistrale at Politecnico of Milano the device was improved by substituting the copper sensors with Printed Circuit Board (PCB) capacitive sensors, allowing for a higher reliability of the signal and therefore of the performances and for an easier manufacturing process. This new device has been referred to as the Tongue Trackpad 2.0 (TT2.0). This second version was realized working remotely together with Veronica Bratland, Master student at UIC conducting her research into the WTSE Lab. The Tongue Trackpad 2.0 is a pointing device, allowing to interact with a screen by moving the cursor with swipes of the tongue on its surface and to select elements through a click gesture. For this reason the Fitt’s Law, a method for evaluating human performance into the selection of an object over an interface, was assessed, by instructing subjects to perform the Multi- Dimensional Tapping Test, which provides the Throughput, a measure unifying accuracy and speed into the selection of a target. Tests to assess the Tongue Trackpad as a typing tool were also performed through an on-screen keyboard, to retrieve a Correct Characters Per Minute (CCPM) value, that can be compared with other published intraoral assistive devices.
Negli ultimi anni e soprattutto nel corso dell’ultimo anno, a causa della pandemia da Covid-19, è diventato centrale il ruolo della comunicazione digitale nelle nostre vite. Per le persone affette da disabilità agli arti superiori avere un accesso facile e comodo ai dispositivi digitali può essere complicato. Questa tesi illustra lo sviluppo di un'implementazione di successo di un dispositivo di assistenza finalizzato a migliorare la vita digitale delle persone con disabilità degli arti superiori, attraverso la funzionalizzazione della loro lingua, organo che di solito risulta inalterato in seguito a lesioni del midollo spinale o ad ictus. Nel Laboratorio Wearable and Sensory Enhancement (WTSE) di Chicago abbiamo sviluppato un dispositivo dotato di sensori capacitivi, il Tongue Trackpad (TT), che si inserisce nella cavità orale e che funge da trackpad controllato attraverso l’estremità finale della lingua. Il dispositivo consente un modo discreto di interagire con un'interfaccia digitale per le persone con disabilità, infatti in quanto inserito all’interno della bocca limita la stigmatizzazione dell'utente. Il rilevamento di un tocco funziona per auto-capacità: un segnale viene applicato sequenzialmente alle colonne e alle righe del Tongue Trackpad e viene quindi misurata la variazione di voltaggio corrispondente, per potere calcolare cambiamenti nella capacità del sensore, che dovrebbero verificarsi in presenza di un tocco. Il nostro dispositivo è resistente ai liquidi, il che significa che mentre un segnale di scansione viene applicato a un determinato sensore, un segnale di schermatura (Shield Signal) viene applicato a tutti gli altri, riducendo la capacità parassita altrimenti indotta dalla presenza di saliva nella cavità orale. Il Tongue Trackpad può essere collegato a qualsiasi dispositivo digitale che supporti il protocollo Human Interface Device (HID), quindi può essere utilizzato per controllare qualsiasi smartphone, computer o tablet dotato di sistema operativo iOS o Android in quanto viene automaticamente riconosciuto come Mouse Bluetooth. Ho sviluppato una prima versione del Tongue Trackpad all'interno del Wearables Technologies and Sensory Enhancement Laboratory (WTSE Lab) a Chicago per la tesi di laurea presso la University of Illinois at Chicago (UIC). Il dispositivo è stato realizzato in tre versioni: uno con matrice 5x5, uno 7x5 e l’altro con matrice 8x7 di sensori capacitivi stampati su un foglio di rame, i cui collegamenti sono inseriti in connettori Zero Insertion Force (ZIF), connessi ad un microcontrollore PSoC (Cypress Semiconductor Corporation). Per il completamento della Tesi Magistrale al Politecnico di Milano il dispositivo è stato migliorato sostituendo i sensori in rame con sensori capacitivi disegnati direttamente sulla scheda elettronica (PCB), consentendo una maggiore affidabilità del segnale e quindi delle prestazioni e per ottenere un processo di fabbricazione più semplice. Il nuovo dispositivo è stato denominato Tongue Trackpad 2.0 (TT2.0). Questa seconda versione è stata realizzata lavorando in remoto insieme a Veronica Bratland, studentessa impegnata in un Master presso l'University of Illinois at Chicago (UIC) e che svolge ricerca nel WTSE Lab. Il Tongue Trackpad 2.0 è un dispositivo di puntamento, che permette di interagire con uno schermo muovendo il cursore tramite tocchi sulla sua superficie eseguiti attraverso la lingua e di selezionare gli elementi tramite un click. Per questo motivo, la Legge di Fitt, un metodo per valutare le prestazioni umane nella selezione di un target all’interno di un’interfaccia, è stata valutata istruendo i soggetti ad eseguire il Multi-Dimensional Tapping Test, da cui è possibile ricavare il Throughput, una misura che unisce precisione e velocità nella selezione di un obiettivo. Test per valutare il Tongue Trackpad come strumento di scrittura sono stati inoltre eseguiti tramite una on-screen keyboard, per calcolare un valore di Correct Characters Per Minute (CCPM) che possa essere confrontato con altri dispositivi di assistenza intra-orali pubblicati in letteratura.
Tongue Trackpad 2.0 : improvement on an augmentative and an assistive device aimed at enhancing the digital life
Bondavalli, Davide
2020/2021
Abstract
During the last years and especially in the last year, due to the Covid 19 pandemic, it became central the role of digital communication into our lives. However, for people affected by upper limb impairment having an easy and comfortable access to digital devices can be challenging. This thesis illustrates the development of a successful implementation of an assistive device aimed at enhancing the digital life of people with upper limb impairment through the functionalization of their tongue, organ which usually results unaffected from Spinal Cord Injury or Stroke. In the Wearable Technology and Sensory Enhancement (WTSE) Laboratory in Chicago we developed a device featuring capacitive sensors, the Tongue Trackpad (TT), which is inserted in the oral cavity and acts as a trackpad controlled through the tip of the tongue. The device enables a discrete way of interacting with a digital interface for people with disability: it’s indeed inserted in the mouth, therefore limiting the stigmatization of the user. The detection of a touch signal works by self-capacitance, meaning that a scanning signal is sequentially applied to the columns and rows of the Tongue Trackpad and the correspondent change in voltage is measured to obtain changes in the sensors capacitance, which happen if a touch is present. Our device is liquids tolerant: while a scanning signal is applied to one sensor, a shield signal is applied to all the others thus reducing the false touch signals otherwise induced by the presence of saliva in the mouth environment. The Tongue Trackpad can be linked to any digital device supporting the Human Interface Device (HID) protocol, therefore it can be employed to control any smartphone, computer or tablet either iOS or Android because it’s recognized as a Bluetooth Mouse. I developed a first iteration of the Tongue Trackpad inside of the Wearable Technology and Sensory Enhancement Laboratory (WTSE Lab) in Chicago for the Master Thesis at the University of Illinois at Chicago (UIC). The device was realized in three versions: a 5x5, a 7x5 and a 8x7 matrices of capacitive sensors printed on a copper sheet, whose traces are inserted into Zero Insertion Force (ZIF) connectors which carry the signals to a PSoC micontroller (Cypress Semiconductor Corporation). For the Thesis Magistrale at Politecnico of Milano the device was improved by substituting the copper sensors with Printed Circuit Board (PCB) capacitive sensors, allowing for a higher reliability of the signal and therefore of the performances and for an easier manufacturing process. This new device has been referred to as the Tongue Trackpad 2.0 (TT2.0). This second version was realized working remotely together with Veronica Bratland, Master student at UIC conducting her research into the WTSE Lab. The Tongue Trackpad 2.0 is a pointing device, allowing to interact with a screen by moving the cursor with swipes of the tongue on its surface and to select elements through a click gesture. For this reason the Fitt’s Law, a method for evaluating human performance into the selection of an object over an interface, was assessed, by instructing subjects to perform the Multi- Dimensional Tapping Test, which provides the Throughput, a measure unifying accuracy and speed into the selection of a target. Tests to assess the Tongue Trackpad as a typing tool were also performed through an on-screen keyboard, to retrieve a Correct Characters Per Minute (CCPM) value, that can be compared with other published intraoral assistive devices.| File | Dimensione | Formato | |
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Tesi - Davide Bondavalli 10528838.pdf
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Descrizione: Improvement on the Tongue Trackpad
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8.52 MB
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https://hdl.handle.net/10589/175590