Sequino

3D Printer (generic)

Soldering iron (generic)

24byj48 1:64 stepper motors

stepstick a4982

ir reflective sensor

nano cnc shield

Arduino Nano R3

3mm 2gt belt

hall sensor

602 bearings

<h3 >Description</h3>This project is a continuation of my quest to build a robotic clock which can write and rewrite the time continuously day in and day out and keep going doing it. My first attempt with doodle clock was a failure due to the marker drying up and the second attempt with doodle#2 failed as the display got scratched very soon .This clock was inspired by my daughters t shirt with the pattern changing sequin cloth glued to it. After getting some stock fabric from a vendor i figured out the size of the clock based on the minimum resolution of the cloth . The fabric has circles of 5mm stitched 3 mm apart. Also another limit of the clock was my printer bed size of 245x170mm . <h3 >Details</h3><div class="se-component se-video-container __se__float-none" contenteditable="false" style="width: 100%;"><figure style="width: 100%; height: 56.25%; padding-bottom: 56.25%; margin: 0px;"><iframe frameborder="0" allowfullscreen="" src="https://www.youtube.com/embed/6jpsiIsMG8U" data-proportion="true" data-percentage="100%,56.25%" data-size="100%,56.25%" data-align="none" style="width: 100%; height: 100%;" data-index="0" data-file-size="0" data-origin="100%,56.25%"></iframe></figure></div><figure><img src=https://projects.arduinocontent.cc/5d1adaf2-b266-43c3-9180-db16dc87bfe5.jpeg /><figcaption> </figcaption></figure><figure><img src=https://projects.arduinocontent.cc/3482ee43-7505-4290-9535-da0467acad1e.jpeg /><figcaption> </figcaption></figure><figure><img src=https://projects.arduinocontent.cc/7c04ee33-a613-4450-b2ef-a24f91d3e9c6.jpeg /><figcaption> </figcaption></figure><figure><img src=https://projects.arduinocontent.cc/8c630f2a-66ce-407d-8fdd-157b641f9762.jpeg /><figcaption> </figcaption></figure>The kinematicsThe kinematics of the clock consists of a mix of h-bot and Cartesian system. The y axis consists of the two rings on the extreme ends of the clock driven by 2 24byj48 motors . The rings are basically gears constrained in outer rings similar to a hubless wheel. The x-axis consists of a strut holding the two rings together and driving a belt routed on a h-bot based path. The belt is driven by two motors. The motors when moving in the same direction move the pen carriage left or right on the x-axis while when then move in the opposite direction move the pen up or down. <figure><img src=https://projects.arduinocontent.cc/4e7737f5-2325-4c35-b5e2-65f6a0f16ece.jpg /><figcaption> </figcaption></figure>Figuring out the cloth backing The Sequin cloth consists of disks which are stitched to a a fabric backing. The Disks flip easily with a finger as they are mounted on a t-shirt or a bag which has a soft backing .But the moment i mounted it on cylinder it stopped flipping as the disks got over constrained by the hard backing . First i tried a ribbed structure as a backing with the fabric stretched on it. It worked but made it very complicated to construct. Finally i figured it out that a simpler way was to just add a 3 mm sponge as a backing to the cloth to give the disks the freedom to flip.<figure><img src=https://projects.arduinocontent.cc/10f4c440-7dda-494d-b7d9-deebd95be886.jpg /><figcaption> </figcaption></figure>The tip of the penThe tip of the pen was very tricky to figure out. Getting a material to act like the tip of a human finger is not very simple. The disks are very slipper and need just the right friction to flip them.  The final solution was tip make of Tpu with a split hook. <figure><img src=https://projects.arduinocontent.cc/15723b8d-6c15-472a-844c-4a22451fac1f.jpg /><figcaption> </figcaption></figure>

Sequino

A clock which rewrites time again and again.