Flashing An LED The Widlar Way

Regular Hackaday readers will be familiar with the work of Boldport’s [Saar Drimer] in creating beauty in printed circuit board design. A recent work of his is the Widlar, a tribute to the legendary integrated circuit designer [Bob Widlar] in the form of a development board for his μA723 voltage regulator chip.

The μA723 is a kit of parts from which almost any regulator configuration can be made, but for [tardate]  it represented a challenge. The μA723 is so versatile that what you can create is only limited by the imagination of the builder. Having done the ordinary before, [tardate] looked toward something unconventional.

The result is modest, a simple LED flasher using the error amplifier as a not-very-good op-amp, building an oscillator at a frequency of about 2 Hz. This is pretty neat and if you are used to the NE555 as the universal integrated circuit, perhaps it’s time to set it aside for the obviously far-more-useful μA723.

Here at Hackaday we harbour at least one fan of the μA723, not to mention also of artful PCBs. If the Widlar looks familiar, we featured the switch mode regulator from the μA723 data sheet on it a few months ago.

Disclosure: [Jenny List] wrote the documentation for Boldport’s Widlar kit.

Pic16maze secret maze game

PIC16Maze Upgrades Secret Maze Game

We really like it when a reader is inspired by something they see on Hackaday, build on it, and let us know so we can pass it on. In this case, [Vegipete] made a secret maze game using a minimal number of parts and some neat software trickery.

It’s built around an 8-pin PIC16F18313 microcontroller, uses a joystick for input, and nine WS2812 LEDs to display the player and the surrounding maze walls. His inspiration was [David Johnson-Davies’] minimalist secret maze game built around the 8-pin ATTiny85. In that one, [David] cleverly used charlieplexing to get four pins to control four LEDs and four pushbuttons. [Vegipete’s] use of the WS2812 LEDs allowed him to control the LEDs with just one pin, and also get color while using three pins for the joystick and its button. He may use another pin in the future for sound and vibration.

He goes into some detail on the WS2812 protocol, how communication is done with the LEDs using just one pin and different pulse-lengths to represent 0 and 1. We’ll leave you to see his post for more depth but basically, he introduces a module on the PIC called the Configurable Logic Cell (CLC) which makes this easy and frees up processor cycles for the user’s code to do other things.

Secret maze wall bitsHis source code is available on request but he does detail a neat software trick he uses for rotating the view. It may be confusing for some but as you move through the maze, your viewpoint rotates so that up is always the direction you’re facing. Luckily, the walls surrounding the user can be represented using 8-bits, four for east, west, north, and south, and four more for the corners. The maze is stored as a bitmap and from it, 8-bit values are extracted for the current position, each bit representing a wall around the position. To rotate the walls to match the user’s current orientation, the bits are simply shifted as needed. Then they’re shifted out to set each LED. Check it out in the video below.

It works very well despite the minimal interface and part count.

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Broken Screen Becomes Polarizing Art Lamp

Got a broken laptop screen sitting around? If you haven’t already pilfered the LEDs and used the polarizing sheets for screen privacy filters, why not turn it into a unique table lamp? See if you can use more parts of the screen than [alexmaree-ross] did.

This is a simple idea with great-looking results, but the process is a bit fiddly. After all the layers are separated and the LEDs extracted, there’s still the matter of figuring out how they’re wired up. [alexmaree] tested them in pairs to see how they’re grouped together and ultimately powered them with a transformer from an old printer. To build the case, [alexmaree] carefully scored and snapped the pieces from the plastic layer and carefully glued pieces of the polarizing layer on top to give it that underwater infinity mirror look. The finishing touch comes from edging the shade with thin metal from the bezel.

The case could be in any shape you want, but we think the prism is quite appropriate considering the polarizing effects. And it looks really cool when you walk around it, which you can do vicariously after the break.

If the screen still works but laptop doesn’t, why not drive it with an FPGA?

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Is That A Tweet On Your Belt Buckle Or Are You Just Happy To See Me?

What a time to be alive! The range of things you never knew you needed but absolutely must have expands at a breakneck pace, such that it’s now possible to pick up a belt buckle with an embedded LED matrix to scroll messages. We have no idea what the use case for something like this is, but some people will buy anything.

One such person was a friend of [Brian Moreau], who doubled down after being gifted the glowing bauble by turning it into a WiFi enabled Tweet-scrolling belt buckle. It appears to be a just for fun project, and to be honest one would need a heck of a belt for the buckle after his mods. He added an ESP8266 to take care of monitoring his Twitter account and driving the display on the belt buckle, a non-trivial task given that the thing is programmed with only two buttons that scroll through characters to compose a message. The microcontroller might have fit inside the original buckle or only added a little to its bulk, but [Brian] decided to replace the two coin cells powering it with an external 6-volt battery pack. That required a buck converter to power the ESP, so the whole thing ended up being thrown in a case and acting more like a neat display than a flashy fashion statement.

We’d bet some tradeoffs could be made to reduce the bulk and get that buckle back where it belongs, though. Once it does, maybe it’ll be part of a complete LED-laden ensemble, from head to toe.

Glow In The Dark Globe On A Spherical Screen

Terrestrial globes are almost a thing of the past in an era of Google Earth, but they can still be an exciting object worth hacking together, as [Ivan Miranda] shows with his glow-in-the-dark globe. It’s a globe, it’s a display, and it’s a great use of glow in the dark filament.

For the mechanical part of this build, [Miranda] used glow in the dark filament to 3D print a sphere and a reinforcing ring that hides inside. A threaded rod through the middle secured with screws and bearings make an appropriate spindle, and is attached to a stepper motor in the 3D printed stand. So far, it’s a sphere made of glowey plastic. Where’s the ‘globe’ part coming from?

To project a globe onto this sphere, [Miranda] used a strip of WS2812B LEDs stuck to the inside of the stand’s arc are programmed to selectively illuminate the globe as it rotates on its axis. After a brief hiccup with getting the proper power supply, he was ready to test out his new….. giant light ball.

It turns out, the filament was a bit more transparent than he was expecting so he had to pull it all apart and cover the interior with aluminium tape. [Miranda] also took the chance to clean up the wiring, code, and upgrade to a Teensy 3.1 before another test.

Despite the resulting continental projection being upside-down, it worked! [Miranda] added a USB cable before he closed it up again in case he wanted to reprogram it and display any number of images down the line.

[Thanks for the tip, olivekrystal!]

Crawling A Dungeon, 64 Pixels At A Time

The trend in video games is toward not being able to differentiate them from live-action theatrical releases, and games studios are getting hard to tell from movie studios. But quality graphics don’t always translate into quality gameplay, and a lot can be accomplished with minimalist graphics. Turn the clock back a few decades and think about the quarters sucked up by classics like Pac-Man, Space Invaders, and even Pong if you have any doubts about that.

But even Pong had more than 64 pixels to work with, which is why this dungeon-crawler game on an 8×8 RGB matrix is so intriguing. You might think [Stolistic]’s game would be as simple as possible but think again. The video below shows it in action, and while new users will need a little help figuring out what the various colors mean, the game is remarkably engaging. The structure of the dungeon is random with multiple levels to unlock via the contents of power-up chests, and there are mobs to battle in a zoomed-in display. The game runs on an Arduino Uno and the matrix is driven by a bunch of 74HC595 shift registers.

It’s fun to see what can be accomplished with as little as possible. Looking for more low-res goodness? Check out this minimalist animated display, or a Geiger counter with a matrix display.

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Simple Home-built Projection Clock Projects Time

There are plenty of cheap projection clocks available, but as [Thomas Pototschnig] points out in this project, where’s the fun in just buying something? He set out to build a cheap projection clock using a small LCD screen, a cheap LED backlight, and a cheap lens. Cheap is the order of the day here, and [Thomas] succeeded admirably, creating a design that can be made with a couple of cheap PCBs, a 3D printer and the other parts mentioned above. He does a nice job of laying out his thinking in this design, showing how he calculated the projection path and made other decisions. His project has room to grow as well: it runs from an Arduino compatible STM32 that could handle many things other than showing the time if you were inclined to expand the project further.

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