Project :: ECE 445 - Senior Design Laboratory

#	Title	Team Members	TA	Documents	Sponsor
17	LED Persistence of Vision Globe	Gavi Campbell Melvin Alpizar Arrieta Owen Bowers	Gayatri Chandran	other1.pdf
	# Team: Globetrotters (WIP) # Team Members: - Owen Bowers (obowers2) - Melvin Alpizar Arrieta (malpi2) - Gavriel Campbell (gcampb7) # Problem LabEscape at UIUC is a popular attraction during events such as Engineering Open House and as such is constantly looking for ways to improve their exhibit. One such improvement they are looking to make is the implementation of a LED Globe capable of displaying messages and images via the utilization of something called persistence of vision. However, many issues can arise when trying to construct a functional system to utilize this phenomenon including mechanical, timing, and electrical restrictions. A couple examples of the problems that may be encountered are as follows: Difficulty in the creation of an electrical system that functions within a rapidly spinning environment. Difficulty acquiring proper live measurements of the systems spin rate. Difficulty translating spin rate into signals at proper time intervals for the entirety of the LED strip across the arch. Difficulty ensuring proper resolution for crisp imaging. Difficulty ensuring stability of the structure due to weights of parts. This problem is emphasized when applied to spinning objects. Additionally to all the above mentioned crucial issues to consider, there are a number of aesthetic issues that should be addressed. Namely, the noise of such a device should ideally be as little as possible and the color spectrum be as large as able. # Solution In order to address the many problems one could encounter when trying to build a system of this kind we plan to take the following measures. We will implement systems capable of acquiring the correct spin rate of the device, taking into account information from accelerometers, optical sensors, and the assumed spin rate of components. We will include a number of LED’s sufficient to provide clear and crisp images across the entirety of the spin radius. We will strive to manage external wiring and focus on keeping all relevant wiring components contained to the PCB board to ensure that wires will not tangle the device and result in catastrophic failure. To solve balancing issues we intend to create a tri-pylon approach where there will be three identical arches spaced around the structure to ensure that balance is maintained. Additionally we will ensure that PCB are spaced properly to distribute weight evenly. This design could be expanded to make use of an RGB coloring system to allow for multicolored display. ## Subsystem 1 - Power Unit A 5 volt power unit will allow for the safe operation of our LED’s avoiding risk of burnout. A wired power source system (DC 12V) and conversion to lower voltage for when it is desired for the device to run for extended periods of time. A mobile battery pack that can be utilized when mobility is desired. ## Subsystem 2 - Motor A DC motor capable of rotating at least 600 rpm should be more than satisfactory for the goal we wish to achieve in this project. WIll be able to rotate the mass of our globe for extended periods of time without wearing out. ## Subsystem 3 - Microprocessor Room for additional features should we wish to expand the scope of our project (such as perhaps the addition of a speaker). Capability to route all our necessary components with ease and the ability to accommodate additional power if needed. Our Microprocessor will allow for WIFI and bluetooth connectivity capabilities. ## Subsystem 4 - Accelerometer/Rotational Sensors An accelerometer to gather experimental data of the current rotational speed of the LED globe An optical sensor will be used with a reference point to verify the correct rotational speed of the globe. Alternatively a hall-effect sensor can be used to magnetically detect rotations and adjust light timing accordingly. ## Subsystem 5 - Multi-Colored LED Band(s) Balanced LED spacing around the PCB core to ensure the smooth rotation of our globe and avoiding turbulence. Reliable and fast acting LED’s not prone to burnout when activated actively and continuously. Bands of interconnected LED’s capable of a single or multiple colors. ## Subsystem 6 - Data Input An SD card reader or item of a similar nature that can accept physical information and display in a sequential order. Support for wireless data transfers to accomplish data displays without the necessity to stop and load the device. Support for an approachable user interface in which displays can be freely edited and changed wirelessly. ## Subsystem 7 - Web Application Will provide a user-friendly method to control the LED Globe Will allow users to upload media files (images, videos, gifs) directly from their device to the globe The web interface will connect to the globe via onboard WiFi/Bluetooth for seamless control. Password protection or local hosting will restrict access so only authorized users can make changes. # Criterion For Success This project will be successful if we meet the following criteria: High resolution displayable text and imaging. Continuous correct functioning for 12 hours when on battery power. Wireless Customizable Graphics.

Featured Project

# Oxygen Delivery Robot

Team Members:

- Rutvik Sayankar (rutviks2)

- Aidan Dunican (dunican2)

- Nazar Kalyniouk (nazark2)

# Problem

Children's interstitial and diffuse lung disease (ChILD) is a collection of diseases or disorders. These diseases cause a thickening of the interstitium (the tissue that extends throughout the lungs) due to scarring, inflammation, or fluid buildup. This eventually affects a patient’s ability to breathe and distribute enough oxygen to the blood.

Numerous children experience the impact of this situation, requiring supplemental oxygen for their daily activities. It hampers the mobility and freedom of young infants, diminishing their growth and confidence. Moreover, parents face an increased burden, not only caring for their child but also having to be directly involved in managing the oxygen tank as their child moves around.

# Solution

Given the absence of relevant solutions in the current market, our project aims to ease the challenges faced by parents and provide the freedom for young children to explore their surroundings. As a proof of concept for an affordable solution, we propose a three-wheeled omnidirectional mobile robot capable of supporting filled oxygen tanks in the size range of M-2 to M-9, weighing 1 - 6kg (2.2 - 13.2 lbs) respectively (when full). Due to time constraints in the class and the objective to demonstrate the feasibility of a low-cost device, we plan to construct a robot at a ~50% scale of the proposed solution. Consequently, our robot will handle simulated weights/tanks with weights ranging from 0.5 - 3 kg (1.1 - 6.6 lbs).

The robot will have a three-wheeled omni-wheel drive train, incorporating two localization subsystems to ensure redundancy and enhance child safety. The first subsystem focuses on the drivetrain and chassis of the robot, while the second subsystem utilizes ultra-wideband (UWB) transceivers for triangulating the child's location relative to the robot in indoor environments. As for the final subsystem, we intend to use a camera connected to a Raspberry Pi and leverage OpenCV to improve directional accuracy in tracking the child.

As part of the design, we intend to create a PCB in the form of a Raspberry Pi hat, facilitating convenient access to information generated by our computer vision system. The PCB will incorporate essential components for motor control, with an STM microcontroller serving as the project's central processing unit. This microcontroller will manage the drivetrain, analyze UWB localization data, and execute corresponding actions based on the information obtained.

# Solution Components

## Subsystem 1: Drivetrain and Chassis

This subsystem encompasses the drive train for the 3 omni-wheel robot, featuring the use of 3 H-Bridges (L298N - each IC has two H-bridges therefore we plan to incorporate all the hardware such that we may switch to a 4 omni-wheel based drive train if need be) and 3 AndyMark 245 RPM 12V Gearmotors equipped with 2 Channel Encoders. The microcontroller will control the H-bridges. The 3 omni-wheel drive system facilitates zero-degree turning, simplifying the robot's design and reducing costs by minimizing the number of wheels. An omni-wheel is characterized by outer rollers that spin freely about axes in the plane of the wheel, enabling sideways sliding while the wheel propels forward or backward without slip. Alongside the drivetrain, the chassis will incorporate 3 HC-SR04 Ultrasonic sensors (or three bumper-style limit switches - like a Roomba), providing a redundant system to detect potential obstacles in the robot's path.

## Subsystem 2: UWB Localization

This subsystem suggests implementing a module based on the DW1000 Ultra-Wideband (UWB) transceiver IC, similar to the technology found in Apple AirTags. We opt for UWB over Bluetooth due to its significantly superior accuracy, attributed to UWB's precise distance-based approach using time-of-flight (ToF) rather than meer signal strength as in Bluetooth.

This project will require three transceiver ICs, with two acting as "anchors" fixed on the robot. The distance to the third transceiver (referred to as the "tag") will always be calculated relative to the anchors. With the transceivers we are currently considering, at full transmit power, they have to be at least 18" apart to report the range. At minimum power, they work when they are at least 10 inches. For the "tag," we plan to create a compact PCB containing the transceiver, a small coin battery, and other essential components to ensure proper transceiver operation. This device can be attached to a child's shirt using Velcro.

## Subsystem 3: Computer Vision

This subsystem involves using the OpenCV library on a Raspberry Pi equipped with a camera. By employing pre-trained models, we aim to enhance the reliability and directional accuracy of tracking a young child. The plan is to perform all camera-related processing on the Raspberry Pi and subsequently translate the information into a directional command for the robot if necessary. Given that most common STM chips feature I2C buses, we plan to communicate between the Raspberry Pi and our microcontroller through this bus.

## Division of Work:

Given that we already have a 3 omni wheel robot, it is a little bit smaller than our 50% scale but it allows us to immediately begin work on UWB localization and computer vision until a new iteration can be made. Simultaneously, we'll reconfigure the drive train to ensure compatibility with the additional systems we plan to implement, and the ability to move the desired weight. To streamline the process, we'll allocate specific tasks to individual group members – one focusing on UWB, another on Computer Vision, and the third on the drivetrain. This division of work will allow parallel progress on the different aspects of the project.

# Criterion For Success

Omni-wheel drivetrain that can drive in a specified direction.

Close-range object detection system working (can detect objects inside the path of travel).

UWB Localization down to an accuracy of < 1m.

## Current considerations

We are currently in discussion with Greg at the machine shop about switching to a four-wheeled omni-wheel drivetrain due to the increased weight capacity and integrity of the chassis. To address the safety concerns of this particular project, we are planning to implement the following safety measures:

- Limit robot max speed to <5 MPH

- Using Empty Tanks/ simulated weights. At NO point ever will we be working with compressed oxygen. Our goal is just to prove that we can build a robot that can follow a small human.

- We are planning to work extensively to design the base of the robot to be bottom-heavy & wide to prevent the tipping hazard.