Planetary Gears Tell Time In This Ornamental Clock

A clock is perhaps one of the the most popular projects among makers. Most designs we see are purely electronic and do not bother with the often more complicated mechanical part. Instructables user [Looman_projects] though was not afraid of calculating gear ratios and tooth counts for his planetary gear clock.

As shown in the picture, a planetary gear, also known as epicyclic gear, consists of three parts: a central sun gear, planetary gears moving around the sun gear and an outer ring with inward-facing teeth holding it all together. The mechanism dates back to ancient Greece but is still being used in car transmissions and has become quite popular in 3D printing. In his instructable [Looman_projects] has some useful inlinks including an explanation video of how planetary gear sets work and a website helping you to calculate the tooth counts for specific gear ratios. It is also noteworthy that he tried to cut the gears from aluminum with a waterjet which unfortunately failed because the parts were too small. What makes the clock visually stand out is the beautiful ornamental see-through design of the dial plate and hands made from laser-cut wood. Despite the mechanical gearbox, it is not surprising that the driving mechanism is based on ubiquitous pieces of digital electronics including an Arduino Nano, DS3231 RTC module, and a stepper motor. To avoid a cabling mess [Looman_projects] designed a custom PCB that interconnects all the electronics and says he even got some spare PCBs left for people interested in rebuilding the clock.

Actually, this is not the first laser-cut planetary gear clock that we have seen. In case you are wondering about the advantages of planetary gearboxes, you might want to check out how a 3D printed version is lifting an anvil.

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Pushing 3D Printed Wheels And Transmissions To The Limit

What do you do if you want a robot with great mobility? Walking is hard, and wheels are good enough, especially if you use the ‘wheels within wheels’ Mecanum setup. But you need torque, too. That’s what makes this entry into the Hackaday Prize so fantastic. It’s a Mecanum wheel of sorts, with an integrated gear set that produces a phenomenal amount of torque using a small, cheap stepper motor.

The wheel itself if 3D printed and fully parametric, using nylon weed wacker filament for the treads. This allows the wheel to scoot back and forth like a Mecanum wheel, or at the very least like one of those hyper mobile wheeled robots you see from time to time. It goes backwards, forwards, and side to side, and also has a zero turn radius.

A 3D printed Mecanum wheel is great, but how on earth do you drive it? That problem is solved with this hybrid planetary/strain-wave  3D-printed gear set. [Daren] has created a very compact ‘single’ stage gear set that fits right on top of a stepper motor. It’s thin, flat, and has a gear reduction of about 66:1. That’s a lot of torque in a very small package. Both of these projects are combined, and together they represent a freaky wheel with a lot of torque.

Even though [Daren] doesn’t have a robot in mind for this build, these are most certainly the building blocks of a fantastic robot, and a great entry in the Hackaday Prize.

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Gorgeous Engineering Inside Wheels Of A Robotic Trail Buddy

Robots are great in general, and [taylor] is currently working on something a bit unusual: a 3D printed explorer robot to autonomously follow outdoor trails, named Rover. Rover is still under development, and [taylor] recently completed the drive system and body designs, all shared via OnShape.

Rover has 3D printed 4.3:1 reduction planetary gearboxes embedded into each wheel, with off the shelf bearings and brushless motors. A Raspberry Pi sits in the driver’s seat, and the goal is to use a version of NVIDA’s TrailNet framework for GPS-free navigation of paths. As a result, [taylor] hopes to end up with a robotic “trail buddy” that can be made with off-the-shelf components and 3D printed parts.

Moving the motors and gearboxes into the wheels themselves makes for a very small main body to the robot, and it’s more than a bit strange to see the wheel spinning opposite to the wheel’s hub. Check out the video showcasing the latest development of the wheels, embedded below.

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3D Printed Gearbox Lifts An Anvil With Ease

How strong can you make a 3D-printed gearbox. Would you believe strong enough to lift an anvil? [Gear Down For What?] likes testing the limits of 3D printed gearboxes. Honestly, we’re amazed.

3D printing has revolutionized DIY fabrication. But one problem normally associated with 3D printed parts is they can be quite weak unless designed and printed carefully.

Using a whole roll of filament, minus a few grams, [Gear Down For What?] printed out a big planetary gear box with a ratio of 160:1 and added some ball bearings and using a drill as a crank. Setting it up on a hoist, he started testing what it could lift. First it lifted a 70 lb truck tire and then another without any issues. It then went on to lift a 120 lb anvil. So then the truck tires were added back on, lifting a combined weight of 260 lb without the gearbox breaking a sweat.

This is pretty amazing! There have been things like functional 3D-printed car jacks made in the past, however 3D-printed gear teeth are notoriously easily broken unless designed properly. We wonder what it would take to bring this gearbox to the breaking point. If you have a spare roll of filament and some ball bearings, why not give it go yourself? STL files can be found here on Thingiverse.

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Laser-cut Cardboard Planetary Gearset Is Pretty, But Useless

[Shane] made a project that speaks directly to our heart — combining laser cutting, cardboard, and gears. How could it be any better? Well, it could do anything. But that’s quibbling. It’s fun enough just to watch the laser-cut cardboard planetary gears turn. (Video after the break.)

It was made on a laser cutter using the gear extensions for generating gears in Inkscape, everybody’s favorite free SVG editor.

In his writeup, [Shane] touches on all of the relevant details: all of the gear pitches need to be the same, and the number of teeth in the sun gear (in the center) needs to equal the number of teeth in the ring (outside) divided by the number of planets (orbiting, in the middle). So far so good.

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