Yet another perpetual pendulum #Arduino

Michael Wiebusch on acidbourbon posts about building a self-exciting pendulum:

So I found people building perpetual self-exciting pendulums (pendula? pendulae?) and showing them off on youtube. Nice 🙂 So far the most elegant that I know of seems to be THIS ONE by youtube channel [TinselKoala] … which is in turn a “cover version” of some original circuit by David Williams, published in the magazine(?) “Nuts & Volts” in August 2012. The circuit is shown at the very end of TK’s video.

The basic idea is: You have a magnet on a string – the pendulum – which swings by a coil that acts both as a sensor (detecting the magnet is above) and an electromagnetic motor (giving the magnet a repulsive kick). Obviously the kicking has to occur at exactly the right time, i.e. when the magnet just barely swooshed past the center of the coil.

I decided to rely on an Arduino to control the behaviour. You might argue that an Arduino is overkill here, since we already know it can be done with two transistors only. But since a chinese Arduino leonardo clone (pro micro) costs me only 4€ and in return I get fine-tuning of the trigger threshold and FET switching timing and all that in software.

See the video below and the blog post here.

Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.

Join 35,000+ makers on Adafruit’s Discord channels and be part of the community!

Have an amazing project to share? The Electronics Show and Tell is every Wednesday at 7pm ET! To join, head over to YouTube and check out the show’s live chat – we’ll post the link there.

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Follow Adafruit on Instagram for top secret new products, behinds the scenes and more

CircuitPython – The easiest way to program microcontrollers –

Maker Business — Moving manufacturing out of China

Wearables — Zip it, zip it good

Electronics — When to opt for alkaline batteries

Python for Microcontrollers — Python on Microcontrollers Newsletter: Arduino 2.0, Podcasts and much more! #CircuitPython @micropython @ThePSF @Raspberry_Pi

Adafruit IoT Monthly — BBQ Smoker, Emoji Telegraph, and more!

Microsoft MakeCode — MakeCode Thank You!

EYE on NPI — Maxim’s Himalaya uSLIC Step-Down Power Module #EyeOnNPI @maximintegrated @digikey

New Products – Adafruit Industries – Makers, hackers, artists, designers and engineers! — New Products 9/21/2022 Featuring Adafruit ENS160 MOX Gas Sensor – Sciosense CCS811 Upgrade – STEMMA QT / Qwiic

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at !

No Comments

No comments yet.

Sorry, the comment form is closed at this time.