Bulbdial clock

3423012113 081C55A4Be
3423014055 5Ef2C1A03F
Evil Mad Scientist Laboratories made an amazing Bulbdial clock

Last year David Friedman published on his blog Ironic Sans an interesting design concept for something that he called The Bulbdial Clock. That’s like a sundial, but with better resolution– not just an hour hand, but a minute and second hand as well, each given as a shadow from moving artificial light sources (bulbs).

We’ve recently put together a working bulbdial clock, with an implementation somewhat different from that of the original concept.

Rather than using three physically moving light sources at different heights, we use three rings of LEDs at different heights. Within each ring, we only turn on one LED at a time, so that we only have a single effective light source, it can light up at different places from within the ring. The three rings are located above one another so that they each project light onto the rod in the middle, making shadows of different lengths.

Additionally, for fun and clarity, we used red, green, and blue LEDs for the three rings, making each shadow hand of the clock a different color. Each ring has 12 LEDs, and the 36 LEDs are efficiently multiplexed by an AVR microcontroller that also handles the timekeeping part of the project.

This clock is mostly built out of laser-cut plywood.


Adafruit publishes a wide range of writing and video content, including interviews and reporting on the maker market and the wider technology world. Our standards page is intended as a guide to best practices that Adafruit uses, as well as an outline of the ethical standards Adafruit aspires to. While Adafruit is not an independent journalistic institution, Adafruit strives to be a fair, informative, and positive voice within the community – check it out here: adafruit.com/editorialstandards

Join Adafruit on Mastodon

Adafruit is on Mastodon, join in! adafruit.com/mastodon

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 code.org, 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.

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!

Join over 36,000+ makers on Adafruit’s Discord channels and be part of the community! http://adafru.it/discord

CircuitPython – The easiest way to program microcontrollers – CircuitPython.org


Maker Business — “Packaging” chips in the US

Wearables — Enclosures help fight body humidity in costumes

Electronics — Transformers: More than meets the eye!

Python for Microcontrollers — Python on Microcontrollers Newsletter: Silicon Labs introduces CircuitPython support, and more! #CircuitPython #Python #micropython @ThePSF @Raspberry_Pi

Adafruit IoT Monthly — Guardian Robot, Weather-wise Umbrella Stand, 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! — #NewProds 7/19/23 Feat. Adafruit Matrix Portal S3 CircuitPython Powered Internet Display!

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



1 Comment

  1. Wow, those folks at EMS make some really cool projects !

Sorry, the comment form is closed at this time.