Simply looking at a traditional analog clock sitting on a wall somewhere got pretty boring for one Instructables user who goes by saulemmetquinn, which is partially why they wanted to create a novel design instead. Their device uses almost entirely 3D-printed components that come together to form the “Holo Clock,” since it seems holographic with its floating minute and hour hands.
The Holo Clock project started with a surprisingly complex design in CAD software. There are two rings that are lined with teeth that sit stacked horizontally. The back ring is the minute hand, and because it is moved almost directly by the stepper motor, it spins more quickly. The hour hand is driven by a set of gears that reduce the output of the minute hand’s cogs by a factor of 60, thus making it turn at the correct rate.
The electronics for the clock are extremely simple. It uses an Arduino Uno with a set of four output wires, along with power and ground, to control a ULN2003 stepper motor driver. This in turn outputs current to a generic 5V stepper motor that spins the first drive gear at a known, precise rate for consistent timing. Likewise, the code is also straightforward, as all it must do is step the motor a certain amount depending on how many steps are left within the loop.
Wheeled robots normally have wheels that move in a single axis and steer by using either differential speeds or by pivoting some kind of guide wheel. However, this leads to some drawbacks, the most obvious being an inability to move in really tight spaces. When presented with this challenge, YouTuber James Bruton came up with a great design for a highly mobile robot platform that employs a novel setup to move in any direction. Inspired by the work of researchers at Osaka University in Japan, the omni wheel uses a single drive shaft to spin, yet nearly every surface has a way to move along the ground.
After designing his robot in Fusion 360 and 3D printing each part, Bruton assembled the wheels and added a pulley to each drive shaft which could be spun by a motor sitting directly above. An Arduino Mega is tasked with controlling each of the three BTS7960 motor drivers and it receives commands via an nRF24L01 radio module. All of the drive components are powered by a single 3-cell LiPo battery pack, while the main board is supplied current by a USB battery bank.
By spinning certain wheels at the correct speed, straight line motion can be produced, as shown in the video below. Bruton tested his robot by driving over carpet, tile, aluminum extrusions, and even a plastic lid, which did very well across everything except the lid. This robot has countless potential uses, such as a garbage collection device for around the house.
It seems like everyone who has a substantial net worth carries around a few luxury watches, but none are perhaps as mechanically enthralling as the Twin Turbo Furious watch from Jacob & Co., which houses a pair of spinning orbs called tourbillons that increase the watch’s accuracy. However, they’re quite small and intricate, so seeing exactly how they work is difficult. This is why mcmaven on Instructables wanted to create a huge 3D-printed version that shows every detailed component.
At the heart is the balance wheel and spring which tick along and keep the time. Further up, the escape wheel works in a ratchet mechanism to slowly load and release the spring as the tourbillon spins. These core components are then placed into the two halves of the body that spins around on the base.
To produce movement, a single 28BYJ-48 stepper motor turns a gear underneath the base to spin the tourbillon. One nice feature of this project is the assembly’s ability to keep a consistent speed through the use of a rotary encoder, as the previous speed is stored within EEPROM and loaded upon boot. A single Arduino Nano is responsible for controlling the entire system, and as seen in the video, it looks incredible.
In the fictional Marvel Universe, Wolverine has sets of claws that pop out of his hands as if they were natural parts of his body. While a seemingly fantastic concept, myoelectric sensors are able to pick up on muscle movements in order to illicit a response. YouTuber MERT Arduino & Tech decided to take this concept and build a pair of forearm-mounted claws.
The wearable device senses muscle activation via a MyoWare muscle sensor, which sends information on to an Arduino Nano on a custom carrier board. Depending on the signal, it’s able to extend or retract claws, with the help of a servo motor and linkage system.
After being inspired by a beautiful, if rather expensive timepiece, Ira Hart decided to make a 3D-printed clock with 24 analog faces that combine to form a single digital display. The overall device is controlled by a single Arduino Nano, which keeps track of the time using a RTC module. This unit coordinates 24 other Nanos on custom carrier boards, which in turn drive their own little clock face via a pair of steppers and a gear system.
When working together, these 24 clocks can tell the time in very large characters, and even show a variety of kinetic art as it changes from one minute to the next. It looks awesome in the video below, and build info is available in Hart’s project write-up.
LiDAR (or “light detection and ranging”) sensors are all the rage these days, from their potential uses in autonomous vehicles, to their implementation on the iPhone 12. As cool as they are, these (traditionally) spinning sensors tend to be quite expensive, well out of reach for most amateur experimenters. Daniel Hingston, however, has managed to build his own unit for under $40, using an Arduino Uno and a pair of VL53L0X time-of-flight (ToF) sensors.
The lighthouse employs a small gearmotor to rotate the two sensors on top of its cylindrical 3D-printed housing, passing signals to the Arduino via a slip ring. Data can then be visualized using a Processing sketch running on a nearby computer.
As seen at around the 10:00 mark in the video, the setup has been utilized to map out different test enclosures, and could be excellent for use in small robotic applications. More details can be found in Hingston’s tutorial here.