Electromechanical YouTube Sub Counter Trades Clicks For Clacks

April 28, 2019 by Kristina Panos 11 Comments

Acquiring a new YouTube subscriber is a blessed event that deserves far more fanfare than a phone notification. But maybe blinkenlights don’t really do it for you anymore, or you simply prefer to be soothed sonically rather than visually. Well, what could be more satisfying than the crisp clack of an electromechanical 7-segment display? Six of them, of course. These things look great, they sound great, and once they’re set, they don’t need power to stay that way.

These displays switch between black and white by reversing current flow through their electromagnets, so [Zack] turned to the H-bridge in order to use them with DC. One H-bridge for each segment of six displays adds up fast, though. To get around this, [Zack] tied one pole of each electromagnet together for a common signal input, and used the other pole to control each segment individually. Then, he was able to tie all the A segments together, all the B segments, and so on, and only needs 13 H-bridges to do it all.

There was just one thing [Zack] didn’t count on. Once he got the board soldered up and running, the displays started acting funny. The low impedance of the coils was causing them to influence each other over the common path, so he added diode arrays to keep them in line.

[Zack]’s using an ESP32 to get the 411 through the Google API, and four octal serial switches to drive the displays. Even more satisfying than all those clacks is the displays’ operational economy baked into [Zack]’s code—as they count up, any segments common to the first digit and the next digit remain on. Increment your way past the break to check out the build video.

Not focused on numbers, but still want to celebrate each new sub? Try a dancing robot or a Tetris twist.

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Flip Dot Displays Appear With Modernized Drivers

November 29, 2016 by Mike Szczys 52 Comments

Admit it, you’ve always wanted to have your own flip-dot display to play with. Along with split-flap displays, flip-dots have an addictive look and sound that hearkens back half a century but still feels like modern technology. They use a magnetic coil to actuate each pixel — physical discs painted contrasting colors on either side. It means that you really only need electricity when changing the pixel, and that each pixel makes a satisfyingly unobtrusive click when flipped. The only problem with the displays is that they’re notoriously difficult to get your hands on.

Breakfast, a Brooklyn-based hardware firm known for creative marketing installations, unveiled their Flip-Disc Display System this morning. Used displays have come up on the usual sites from time to time, but often without a controller. Traditional flip-dot manufacturers haven’t sought out the individual hacker or hackerspace, and a click-to-buy option has been difficult if not impossible to find.

Breakfast’s offering modernizes the driver used to manage all of those electro-mechanical pixels. Whether this will make the displays more accessible is a question that still needs to be answered.
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Controlling A Flip-Disc Display Using Android

October 20, 2014 by James Hobson 14 Comments

There’s just something about electro-mechanical displays that enthralls most people when they see them; and while you’ll be hard pressed to find a split-flap display for cheap, you can still easily buy flip-disc displays! That’s what [Scott] did, and he’s been having a blast messing around with his and building a system to control it via his Android phone.

He picked up the display from a company called Alfa-Zeta in Poland, a company that’s been making electromagnetic displays since 1988. No mention of price, but it looks like some pretty awesome hardware. The beauty with electromagnetic displays is they don’t consume any electricity in idle state, making them far more efficient than almost any other display technology – not to mention perfect contrast in any lighting conditions!

They work by using permanent magnets, electromagnets, and a material that can retain magnetization. A short pulse to the electromagnet causes the disc to flip into the second position, which will then hold in place due to the permanent magnet — no more electromagnet needed.

The display comes with all the necessary hardware to drive the electromagnets and interface with a microcontroller. But, it uses the RS-485 standard, which isn’t natively supported by most other microcontrollers. [Scott’s] using an Arduino which does have an RS-485 shield, but he decided he wanted to challenge himself and build a circuit to drive them himself!

All the info is on his blog if you’re looking to try something similar. Once he had it interfaced with the Arduino it was just a simple matter of writing an Android app to transmit controls over Bluetooth for the display. Take a look:

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