NightRydazz

The device is designed to be mounted on the back wheel of a bicycle. It operates using a lithium-ion battery, allowing it to function independently while being attached to the spokes of the rear wheel. All components, with the exception of the magnets that activate the Hall effect sensor, are positioned on the spokes. The battery, Arduino, and LED assembly are all mounted on the spokes, enabling them to spin freely. Prior to determining how the components would be arranged, a circuit schematic was created to ensure proper wiring and connections. The schematic shows that components labeled "D" are connected to various pins on the Arduino, with the pins interfacing with the LEDs via transistors and 1.5K resistors. The component labeled "S" represents the Hall effect sensor.

To secure the components to the wheel, a housing was designed from clear acrylic to fit onto the spokes. A clear acrylic sheet was utilized to create a finger-joint box, with certain joints glued for added strength, although the assembly was stable without adhesive. A laser cutter was employed to fabricate the housing components, which were then assembled. Due to challenges accessing the laser cutter and time constraints, a simpler wooden box was constructed to house the Arduino circuit boards and battery, featuring drilled holes for ventilation and access. This box was secured to the spokes using zip ties for a quick and effective attachment.

As the wheel rotates, the Hall effect sensor passes beneath two magnets, causing a momentary change in output. The time interval between consecutive activations is used to calculate the wheel's speed. This speed, combined with the time elapsed since the last activation, allows for determining the position of the LED display on the wheel. By identifying which pixels should be illuminated based on the wheel's current position, a continuous light pattern is created, leveraging the persistence of vision effect. After finalizing the design and preparing the component housings, the next step involved assembling the prototype and attaching it to the bicycle, followed by programming and functionality implementation. The initial task was to solder all components within the LED mounting container. The clear box features a central panel with holes for each LED, transistor, and resistor, facilitating easy insertion and soldering of the components, despite the limited space available.

The circuit schematic for this bicycle-mounted device incorporates a lithium-ion battery as the primary power source, providing energy to the Arduino microcontroller and the LED display. The Hall effect sensor, positioned strategically on the wheel, detects the rotational speed through the magnetic field created by the magnets mounted on the spokes. The Arduino processes the signals from the Hall effect sensor, calculating the speed by measuring the time intervals between activations.

The transistors act as switches, allowing the Arduino to control the LEDs based on the calculated position and speed of the wheel. The 1.5K resistors limit the current flowing through the LEDs, ensuring they operate within safe limits and prolonging their lifespan. The housing design, crafted from clear acrylic, provides a protective enclosure for the components while allowing visibility of the LEDs. This design not only enhances the aesthetic appeal but also ensures durability against environmental factors.

The wooden box serves as a functional alternative for housing the Arduino and battery, designed for quick assembly and easy access. The use of zip ties for mounting provides a reliable method for securing the device to the spokes, allowing for straightforward maintenance and adjustments. Overall, the integration of these components and the thoughtful design of the housing contribute to a robust and efficient system that enhances visibility and safety for cyclists during nighttime rides.The device will be placed on the back wheel of the bicycle. Since the LED`s and other components run off of a lithium-ion battery, it stands independently, attached to the spokes of the rear wheel. In the design, all components are placed on the spokes of the wheel, with the exception of the magnets activating the hall effect sensor.

The battery, Arduino, LED construction, are all placed on the spokes and spin freely. Before designing how the components would fit together, it was imperative to draw out a circuit schematic. If we don`t know how the components will be wired together, where the wires will be, and which components are connected to each other, then how should we design the components` housing We came up with the following schematic as the best solution: The components labeled "D" are wired to the different pins on the Arduino.

The pins are connected to the LED`s through transistors and 1. 5K resistors. The component labelled "S" is the Hall Effect Sensor. In order to attach the components to the wheel, we created housing for the components to fit into and mount onto the spokes of the wheel, made out of clear acrylic. We bought a clear sheet of acrylic, designed a finger joint box that fits together, then glued the parts of the box that received more stress, although it worked pretty well without the glue as well.

We used a laser cutter to cut the pieces out of the acrylic and then snapped them together. The design was as follows: Due to difficultly getting into the lab with the laser cutter and limited time, we didn`t create the same sort of housing for the Arduino circuit boards and battery as we did for the LED`s, but if we had more time, we would have. Instead, we made a rough and quick wooden box, glued together with holes drilled into it to house the boards.

A panel slides in and out to allow for the removal of the boards and battery. We then strapped this to the spokes using zip ties for a fast but durable attachment. It did the job just as we needed it to. As the wheel spins, the hall effect sensor passes under the two magnets, momentarily switching it`s output. Using the time between two consecutive switches, we determine the wheel`s speed. Based on this speed and the time since the last switch, we determine the position of the LED display on the wheel.

Once the position is determined, we merely have to determine which pixels are on at the wheel`s current position and light them up. Lighting the pixels at each location on a quickly moving wheel gives the impression of a constantly lighted pattern - a phenomenon known as persistance of vision.

Once we planned everything and got the component housing ready to put together, it was only a matter of building the prototype and mounting it onto the bike before we could start programming and implementing functionality. The first step was to solder all of the components together within the LED mounting container. The clear box has a center panel with holes cut into it for each LED, transistor, and resistor. The components could be easily inserted into their correct holes and then soldered together. With such a small space for all of the components 🔗 External reference