A Tuning Fork Clock, With Discrete Logic

[Willem Koopman aka Secretbatcave] was looking at a master clock he has in his collection which was quite a noisy device, but wanted to use the matching solenoid slave clock mechanism he had to hand. Willem is a fan of old-school ‘sector’ clocks, so proceeded to build his ideal time piece — Vibrmatic — exactly the way he wanted. Now, since most time keeping devices utilise a crystal oscillator — which is little more than a lump of vibrating quartz — why not scale it up a bit and use the same principle, except with a metal tuning fork? (some profanity, just to warn you!)

Shock-mounted tuning force oscillator

A crystal oscillator operates in a simple manner; you put some electrical energy in, it resonates at its natural frequency, you sense that resonance, and feed it back into it to keep it sustaining. With a tuning fork oscillator, the vibration forcing and the feedback are both done via induction, coils act as the bridge between the electronic and mechanical worlds.

By mounting the tuning fork onto a shock mounting, the 257 Hz drone was kept from leaking out into the case and disturbing the household. This fork was specified to be 256 Hz, but [Willem] reckons the drag of the electromagnets pushed it off frequency a bit. Which make sense, since its a mechanical system, that has extra forces acting upon it.

The sector face was CNC cut from aluminium, the graphics engraved, then polished up a bit. Finally after a spot of paint, it looks pretty smart. Some nice chunks of upcycled wood taken from some building work spoils formed the exposed enclosure. On the electronics side, after totally ignoring the frequency error, and then tripping over a bunch of problems such as harmonics in the oscillation, and an incorrectly set-up divider, a solution which seemed to work was found, but like always, there are quite a few more details to the story to be found in the build log.

We’ve seen a tuning fork clock recently, like this 440 Hz device by [Kris Slyka] that the project above references, and whilst we’re talking about tuning forks, here’s a project log showing the insides of those ubiquitous 32.768 kHz crystal units.

Oliver Heaviside: Rags To Recognition, To Madness

Like any complex topic, electromagnetic theory has its own vocabulary. When speaking about dielectrics we may refer to their permittivity, and discussions on magnetic circuits might find terms like reluctance and inductance bandied about. At a more practical level, a ham radio operator might discuss the impedance of the coaxial cable used to send signals to an antenna that will then be bounced off the ionosphere for long-range communications.

It’s everyday stuff to most of us, but none of this vocabulary would exist if it hadn’t been for Oliver Heaviside, the brilliant but challenging self-taught British electrical engineer and researcher. He coined all these terms and many more in his life-long quest to understand the mysteries of the electromagnetic world, and gave us much of the theoretical basis for telecommunications.

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Visualization Of A Phased Array Antenna System

Phased array antenna systems are at the cusp of ubiquity. We now see Multiple-Input Multiple-Output (MIMO) antenna systems on WiFi routers. Soon phased array weather radar systems will help to predict the weather and keep air travel safe, and phased array base stations will be the backbone of 5G which is the next generation of wireless data communication.  But what is a phased array antenna system?  How do they work?  With the help of 1024 LEDs we’ll show you.

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