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| report:soa [2026/04/25 18:04] – [2.3.4 CAN Bus and MCP2551 transceiver] team5 | report:soa [2026/06/14 15:33] (current) – team5 | ||
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| ==== 2.1 Introduction ==== | ==== 2.1 Introduction ==== | ||
| - | This chapter presents the background research done to develop | + | This chapter presents the background research done to develop |
| - **Interactive urban light installations: | - **Interactive urban light installations: | ||
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| - **Participatory public art:** Research into design principles that create a sense of connection between strangers in shared spaces. | - **Participatory public art:** Research into design principles that create a sense of connection between strangers in shared spaces. | ||
| - **Research: | - **Research: | ||
| - | - **Comparative analysis:** A structured overview of the products, installations, | + | - **Comparative analysis:** A structured overview of the products, installations, |
| ==== 2.2 Products ==== | ==== 2.2 Products ==== | ||
| - | === 2.2.1 Interactive urban light installations | + | == 2.2.1 Interactive urban light installations == |
| Kinetic particles is an interactive art installation that connects human physical movement with digital projections [(kinetic_particles)]. By using cameras and deep learning technology, the system tracks the body movements of performers and audience members in real-time, as illustrated in Figure {{ref> | Kinetic particles is an interactive art installation that connects human physical movement with digital projections [(kinetic_particles)]. By using cameras and deep learning technology, the system tracks the body movements of performers and audience members in real-time, as illustrated in Figure {{ref> | ||
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| - | === 2.2.2 Community stories | + | == 2.2.2 Community stories == |
| This article describes the project Keitai Trail in which researchers used mobile phones to collect and link personal stories from people in public spaces [(numa2009keitai)]. During an art festival, the researchers made a workshop, seen in Figure {{ref> | This article describes the project Keitai Trail in which researchers used mobile phones to collect and link personal stories from people in public spaces [(numa2009keitai)]. During an art festival, the researchers made a workshop, seen in Figure {{ref> | ||
| - | This research is relevant to our project because it demonstrates how technology can be used to collect stories from strangers and connect them in a shared environment. Similar to our concept with QR codes and voice memos in the underground, | + | This research is relevant to our project because it demonstrates how technology can be used to collect stories from strangers and connect them in a shared environment. Similar to our concept with QR codes and |
| <WRAP centeralign> | <WRAP centeralign> | ||
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| - | === 2.2.3 Participatory Public Art === | + | == 2.2.3 Participatory Public Art == |
| This article outlines the evolution of materials used in public art and how new technologies have led to interactive and participatory installations [(publicartinstallations2014)]. The authors categorize art forms into static, dynamic, interactive, | This article outlines the evolution of materials used in public art and how new technologies have led to interactive and participatory installations [(publicartinstallations2014)]. The authors categorize art forms into static, dynamic, interactive, | ||
| - | This article is relevant to Connect | + | This article is relevant to CONNECT and share because it provides a theoretical framework for participatory public art. The examples demonstrate that combining a physical environment with a digital, co-creative layer can foster social interaction between strangers in a shared space. This supports the argument that CONNECT and share's approach, where passengers collectively shape a visual environment through touch follows an established design principle for creating a sense of shared presence. |
| <WRAP centeralign> | <WRAP centeralign> | ||
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| </ | </ | ||
| - | While these installations demonstrate how interactive systems can foster shared experiences, | + | While these installations demonstrate how interactive systems can foster shared experiences, |
| ==== 2.3 Research ==== | ==== 2.3 Research ==== | ||
| - | === 2.3.1 Loneliness in public spaces | + | == 2.3.1 Loneliness in public spaces == |
| - | A central motivation behind | + | A central motivation behind |
| The study found that perceived overcrowding was positively associated with loneliness (OR: 1.39), meaning that being surrounded by many people did not reduce feelings of isolation, it increased them. In contrast, perceived social inclusivity, | The study found that perceived overcrowding was positively associated with loneliness (OR: 1.39), meaning that being surrounded by many people did not reduce feelings of isolation, it increased them. In contrast, perceived social inclusivity, | ||
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| It should be noted that the study has limitations. The sample was self-selected and the main participants was educated, middle-aged, | It should be noted that the study has limitations. The sample was self-selected and the main participants was educated, middle-aged, | ||
| - | Despite these limitations, | + | Despite these limitations, |
| - | === 2.3.2 Microcontroller | + | == 2.3.2 Microcontroller == |
| - | The decision to use a microcontroller from the ESP32 family is supported by a comparative analysis of microcontroller platforms for IoT and embedded systems [(maier2017)]. The study evaluates the ESP32 against comparable boards and concludes that its combination of low cost, low power consumption, | + | The decision to use a microcontroller from the ESP32 family is supported by a comparative analysis of microcontroller platforms for the Internet of Things (IoT) and embedded systems [(maier2017)]. The study evaluates the ESP32 against comparable boards and concludes that its combination of low cost, low power consumption, |
| - | In Connect, the system is distributed across two types of nodes: sensor nodes embedded in each handrail pole, and a central ceiling node that drives the LED strip. Each node handles one task: either reading pressure input from the velostat sensor, or sending colour signals to the LED strip. A single-core microcontroller is sufficient for this, as no parallel processing is required at the node level. The ESP32 microcontroller can handle multiple tasks simultaneously [(maier2017)], | + | In CONNECT and share, the system is distributed across two types of nodes: sensor nodes embedded in each handrail pole, and a central ceiling node that drives the LED strip. Each node handles one task: either reading pressure input from the velostat sensor, or sending colour signals to the LED strip. A single-core microcontroller is sufficient for this, as no parallel processing is required at the node level. The ESP32 microcontroller can handle multiple tasks simultaneously [(maier2017)], |
| The Arduino-compatible development environment shared across the ESP32 family is a practical advantage for our multidisciplinary student team, as it is «beginner-friendly» and have several libraries for both sensor input and LED control [(maier2017)]. | The Arduino-compatible development environment shared across the ESP32 family is a practical advantage for our multidisciplinary student team, as it is «beginner-friendly» and have several libraries for both sensor input and LED control [(maier2017)]. | ||
| - | Maier et al. confirmed that the ESP32-C3 offers sufficient processing capacity for single-task embedded nodes at low power. In Connect, each Sensor Node performs only ADC polling and CAN transmission, | + | Maier et al. confirmed that the ESP32-C3 offers sufficient processing capacity for single-task embedded nodes at low power. In CONNECT and share, each Sensor Node performs only ADC polling and CAN transmission, |
| - | === 2.3.3 Velostat sheet === | + | == 2.3.3 Velostat sheet == |
| - | The decision to use velostat sheets for touch detection in the handrails of Connect | + | The decision to use velostat sheets for touch detection in the handrails of CONNECT and share is grounded in established research on flexible piezoresistive materials. Velostat is a polyethylene-carbon composite material that changes its electrical resistance in response to applied pressure. When compressed, the resistance decreases, producing a measurable electrical signal [(polym12122905)] |
| Dzedzickis et al. evaluated the mechanical and electrical characteristics of velostat as a tactile sensor material, testing it under static, long-term, and cyclic load conditions. | Dzedzickis et al. evaluated the mechanical and electrical characteristics of velostat as a tactile sensor material, testing it under static, long-term, and cyclic load conditions. | ||
| - | The results confirm that velostat produces consistent, repeatable signals across multiple loading cycles, and that it can be implemented using a simple electrode pair [(polym12122905)]. These properties make it well suited for Connect, where the sensor must reliably detect the pressure of a passenger gripping a handrail and produce a signal the ESP32 can read. | + | The results confirm that velostat produces consistent, repeatable signals across multiple loading cycles, and that it can be implemented using a simple electrode pair [(polym12122905)]. These properties make it well suited for CONNECT and share, where the sensor must reliably detect the pressure of a passenger gripping a handrail and produce a signal the ESP32 can read. |
| A practical advantage of velostat for this application is its flexibility. The material is thin and can conform to curved surfaces such as a handrail without requiring rigid mounting. One limitation noted in the research is that velostat' | A practical advantage of velostat for this application is its flexibility. The material is thin and can conform to curved surfaces such as a handrail without requiring rigid mounting. One limitation noted in the research is that velostat' | ||
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| Velostat is not perfectly linear and its sensitivity shifts with repeated use, as Dzedzickis et al. documented under cyclic loading conditions. The Sensor Node PCB addresses this directly: a 10 kΩ potentiometer on the board lets the sensitivity threshold be tuned physically during installation, | Velostat is not perfectly linear and its sensitivity shifts with repeated use, as Dzedzickis et al. documented under cyclic loading conditions. The Sensor Node PCB addresses this directly: a 10 kΩ potentiometer on the board lets the sensitivity threshold be tuned physically during installation, | ||
| - | === 2.3.4 CAN Bus and MCP2551 transceiver | + | == 2.3.4 CAN Bus and MCP2551 transceiver == |
| - | Connect | + | CONNECT and share uses a distributed node architecture: |
| CAN (Controller Area Network) is a serial communication protocol originally developed for automotive applications, | CAN (Controller Area Network) is a serial communication protocol originally developed for automotive applications, | ||
| - | The MCP2551 is a high-speed CAN transceiver developed by Microchip Technology that implements the physical layer of the ISO 11898 standard [(MCP2551)]. It acts as the interface between the microcontroller' | + | The MCP2551 is a high-speed CAN transceiver developed by Microchip Technology that implements the physical layer of the ISO 11898 standard [(MCP2551)]. It acts as the interface between the microcontroller' |
| - | A metro carriage is electrically hostile. Traction motors and power converters produce continuous EMI that would corrupt single-ended protocols like I2C or UART. Bozdal et al. document exactly this weakness in non-differential bus architectures, | + | A metro carriage is electrically hostile. Traction motors and power converters produce continuous EMI that would corrupt single-ended protocols like Inter-Integrated Circuit (I2C) or Universal Asynchronous Receiver-Transmitter (UART). Bozdal et al. document exactly this weakness in non-differential bus architectures, |
| - | === 2.3.5 WS2812B addressable LED strip === | + | == 2.3.5 WS2812B addressable LED strip == |
| The WS2812B is an individually addressable RGB LED component that integrates the control circuit and the RGB emitter into a single 5050-format package [(WORLDSEMI_WS2812B)]. Each unit contains a built-in driver IC that receives colour data, applies it to its own output, and passes the remaining data to the next unit in the chain via a single data line. This daisy-chain architecture | The WS2812B is an individually addressable RGB LED component that integrates the control circuit and the RGB emitter into a single 5050-format package [(WORLDSEMI_WS2812B)]. Each unit contains a built-in driver IC that receives colour data, applies it to its own output, and passes the remaining data to the next unit in the chain via a single data line. This daisy-chain architecture | ||
| means the entire ceiling strip can be controlled from one digital output pin on the microcontroller [(WORLDSEMI_WS2812B)]. | means the entire ceiling strip can be controlled from one digital output pin on the microcontroller [(WORLDSEMI_WS2812B)]. | ||
| - | Individual addressability is essential for Connect's core interaction: | + | Individual addressability is essential for CONNECT and share's core interaction: |
| The strip is compatible with the FastLED library available in the Arduino development environment, | The strip is compatible with the FastLED library available in the Arduino development environment, | ||
| + | CONNECT and share consists of multiple distributed sensor nodes embedded in handrails, each detecting passenger interaction through velostat sensors. These nodes communicate via a CAN bus network to a central controller located in the ceiling, which drives an addressable LED strip to visualise collective interaction. | ||
| - | Connect consists of multiple distributed sensor nodes embedded in handrails, each detecting passenger interaction through velostat sensors. These nodes communicate via a CAN bus network to a central controller located in the ceiling, which drives | + | The component review above evaluated the WS2812B. During implementation, |
| ==== 2.4 Comparative analysis ==== | ==== 2.4 Comparative analysis ==== | ||
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| <table tab_products-table>< | <table tab_products-table>< | ||
| + | <WRAP center round box 1200px> | ||
| ^ Category ^ Technology/ | ^ Category ^ Technology/ | ||
| | Kinetic Particles | Cameras, deep learning, digital projections | Real-time physical movement | Connecting physical movement with a digital environment | Proves that real-time visual feedback pulls people out of their digital bubbles | | | Kinetic Particles | Cameras, deep learning, digital projections | Real-time physical movement | Connecting physical movement with a digital environment | Proves that real-time visual feedback pulls people out of their digital bubbles | | ||
| | Keitai Trail | Mobile phones, large projection screens | Asynchronous (recording Q&A videos) | Collecting and linking personal stories | Supports the use of everyday devices to foster a sense of community | | | Keitai Trail | Mobile phones, large projection screens | Asynchronous (recording Q&A videos) | Collecting and linking personal stories | Supports the use of everyday devices to foster a sense of community | | ||
| | Participatory Installations (Strijp-T-ogether) | Mobile apps, projection mapping, live camera feeds | Real-time and asynchronous digital co-creation | Stimulating social interaction through a shared platform | Provides a theoretical framework for passengers co-creating their metro environment | | | Participatory Installations (Strijp-T-ogether) | Mobile apps, projection mapping, live camera feeds | Real-time and asynchronous digital co-creation | Stimulating social interaction through a shared platform | Provides a theoretical framework for passengers co-creating their metro environment | | ||
| + | </ | ||
| </ | </ | ||
| <table tab_research-table>< | <table tab_research-table>< | ||
| + | <WRAP center round box 1200px> | ||
| ^ Category ^ Method ^ Key Finding ^ Relevance to Connect ^ | ^ Category ^ Method ^ Key Finding ^ Relevance to Connect ^ | ||
| | Hammoud et al. – Lonely in a Crowd | Smartphone-based ecological momentary assessment | Overcrowding increases loneliness; perceived inclusivity reduces it | Confirms the problem Connect aims to address | | | Hammoud et al. – Lonely in a Crowd | Smartphone-based ecological momentary assessment | Overcrowding increases loneliness; perceived inclusivity reduces it | Confirms the problem Connect aims to address | | ||
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| | Microchip Technology – MCP2551 | Component datasheet | Implements the ISO 11898 physical layer, acting as the interface between microcontroller and CAN bus | Justifies the choice of transceiver for each node in the system | | | Microchip Technology – MCP2551 | Component datasheet | Implements the ISO 11898 physical layer, acting as the interface between microcontroller and CAN bus | Justifies the choice of transceiver for each node in the system | | ||
| | WorldSemi – WS2812B | Component datasheet | Individually addressable RGB LED with integrated driver, controllable via a single data line | Justifies the choice of LED component for producing distinct, blendable colours on the ceiling | | | WorldSemi – WS2812B | Component datasheet | Individually addressable RGB LED with integrated driver, controllable via a single data line | Justifies the choice of LED component for producing distinct, blendable colours on the ceiling | | ||
| + | </ | ||
| </ | </ | ||
| ==== 2.5 Summary ==== | ==== 2.5 Summary ==== | ||
| - | This chapter has reviewed existing installations, | + | This chapter has reviewed existing installations, |
| - | literature relevant to Connect. Interactive installations such as Kinetic | + | |
| - | Particles and Strijp-T-ogether demonstrate that real-time visual feedback | + | |
| - | based on physical interaction | + | |
| - | between strangers. Keitai Trail shows that everyday devices can lower the | + | |
| - | threshold for participation | + | |
| - | The research by Hammoud et al. provides | + | Hammoud et al. establish |
| - | the project: overcrowding alone does not reduce loneliness, | + | |
| - | whether people feel acknowledged | + | |
| - | the design goal of Connect. | + | |
| - | On the technical | + | The technical |
| - | use of velostat sheets for pressure detection in the handrails, the WEMOS C3 | + | |
| - | mini as a low-power microcontroller suited to single-task embedded nodes, | + | |
| - | bus as a noise-resistant | + | |
| - | system, | + | |
| - | individually controlled colours across the ceiling | + | |
| - | Together, these sources establish both the problem Connect aims to address and | + | In the next chapter |
| - | the technical foundation | + | |