classic hacks

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A Fruity Approach To CNC Design

July 17, 2019 by 8 Comments

[Frank Howarth] found himself in need of a lamp for his dining room. Being of the maker persuasion, store-bought simply wouldn’t do. With a serious wood shop at his disposal, [Frank] took a trip down to the supermarket for inspiration.

Having picked out a particularly well-formed starfruit for his project, [Frank] didn’t want to spend an inordinately long time attempting to recreate the organic lumps and bumps in modelling software, Instead, Meshroom was used to create a model through photogrammetry. After several failed attempts, success was achieved by using a textured rotating table as a background, with the starfruit painted in matte grey and a final dusting of black speckle. This gave the software enough visual cues to accurately model the fruit’s geometry.

With a 3D model to hand, Fusion Slicer was then used to generate a model that could be constructed out of flat lasercut pieces. The cutting outlines were then generated and passed to Rhino for final tweaking. With everything ready, parts were cut out of plywood and a small mockup of a potential lamp design was created. [Frank] is currently workshopping the design with the inhabitants of the dining room, prior to the final build.

Photogrammetry and modern CAD tools make working with natural forms quick and easy. We’ve also seen the technology used for other purposes too, with [Eric Strebel] providing a great example on how to use it for reverse engineering.

The starfruit tag on Hackaday is pretty sparse, so if you’ve got a project, let us know. Video after the break.

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Pushing Pixels To A Display With VGA Without A PC

July 17, 2019 by 17 Comments

[Ben Eater] is back with the second part of his video series on building a simple video card that can output 200×600 pixels to a display with nothing but a VGA connection, a handful of 74-logic chips and a 10 MHz crystal. In this installment we see how he uses nothing but an EEPROM and a handful of resistors to get an image onto the screen.

The interesting part is in how the image data is encoded into the EEPROM, since it has to be addressable by the same timing circuit as what is being used for the horizontal and vertical timing. By selecting the relevant inputs that’d make a valid address, and by doubling the size of each pixel a few times, a 100 x 75 pixel image can be encoded into the EEPROM and directly addressed using this timing circuit.

The output from the EEPROM itself not fed directly into the monitor, as the VGA interface expects a 0 V to 0.7 V signal on each RGB pin, indicating the brightness. To get more than three colors out of this setup, [Ben] builds up a simple 2-bit DAC that allows for two bits per channel, meaning four brightness levels per color channel or 64 colors effectively.

See the video after the link for the full details. While pretty close to perfect, a small issue remains at the end in the forms of black vertical lines. These are caused by a timing issue in the circuit, with comments on the YouTube video suggesting various other potential fixes. Have you breadboarded your own version yet to debug this issue before [Ben]’s next video comes out?
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The Trials And Tribulations Of Building An IOT Garage Door Opener

July 15, 2019 by 18 Comments

Garage doors can be frustrating things, being a chore to open manually and all. Many people opt to install a motorized opener, but for some, even this isn’t enough. Hooking up a garage door to the Internet of Things has long been a popular project, and [Simon Ludborzs] decided to give it a shot. Naturally, there were some obstacles to be overcome along the way.

[Simon]’s build is relatively straight down the lines, using an ESP-12 as the brains of the operation, which connects to the internet over WiFi. However, robustness was a major goal of the project, and being reliant on shaky cloud-based services wouldn’t do. This opener is set up to work independently of an internet connection, too. There’s a nifty control panel with glowing buttons to operate the opener, in addition to the webpage served up on the network.

During the development, [Simon] ran into several roadblocks. A set of roller door motors were inadvertently killed, and there were issues in getting the web interface working as expected. None of these were showstoppers, though, and with a little work and some new parts, everything came together in the end. The project was then given a proper commercial-grade case, sourced from AliBaba. This is a great step to take for a project expected to hold up to daily use for years on end. He also took the time to document his tips for easier ESP8266 development, which may prove useful to those just getting started with the platform.

Garage door openers remain a common theme around here, but every project has its own story to tell. If you’ve developed a particularly unique solution to your garage access problems, you know who to call.

Minivac 601 Replica Gets A Custom Motorized Rotary Switch

July 13, 2019 by 2 Comments

One of the joys of electronics as a hobby is how easy it is to get parts. Literally millions of parts are available from thousands of suppliers and hundreds of distributors, and everyone competes with each other to make it as easy as possible to put together an order from a BoM. If you need it, somebody probably has it.

But what do you do when you need a part that doesn’t exist anymore, and even when it did was only produced in small numbers? Easy – you create it yourself. That’s just what [Mike Gardi] did with this unique motorized rotary switch he needed to complete his replica of a 1960s computer trainer. We covered his build of the Minivac 601, a trainer from the early computer age that let experimenters learn the ropes of basic digital logic. It used mostly relays, lamps, and switches connected by jumpers, but it had one critical component – a rotary control that was used for input and, with the help of a motor, as an output indicator.

[Mike]’s version of the switch is as faithful to the original as possible, at least in terms of looks. The parts are mostly 3D-printed, with 16 reed switches embedded in the walls and magnets placed in the rotor. The motor to operate the rotor is a simple gear motor mounted to a hinged bracket; when the rotor needs to move, a solenoid pulls the motor’s friction drive wheel up against the rotor.

The unique control slots right into the Minivac replica and really completes the look and feel. Hats off to [Mike] for a delightful replica of a lost bit of computer history and the dedication to see it through to completion.

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Simple Simon Says Looks Sharp

July 12, 2019 by 4 Comments

Simon was a popular toy, launching at the very end of the 1970s, and cribbed from earlier work by Atari with their game Touch Me. The gameplay is simple, and while we suspect it won’t last quite as long as the several thousand years we’ve so far had chess, it’s still around today. [DIY Machines] decided to bust out the 3D printer and whip up their own version.

Simon has long served as a great test project to get to grips with various maker skills, and this build is no exception. An Arduino Nano runs the show, and gets an OLED display to display the current level. Large glowing arcade buttons serve as the control, with their lights flashed as per the original game. Sound is courtesy of a simple buzzer.

It’s a build that doesn’t do anything wild, but presents very well. This is down to the smoothly finished and nicely designed case, as well as the choice of quality human interface components. Everyone loves mashing arcade buttons, and that’s what they’re built for – so they’re always a safe choice.

We’ve seen a lot of straight-down-the-lines Simon projects, but this DDR-ified version is a fun twist on the standard form. Video after the break.

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Motorized Lens Controller Techs Up Your Webcam

July 11, 2019 by 13 Comments

If you’re familiar with the DSLR camera market, you’d know that modern lenses are works of technological art. Crammed full of motors and delicate electronic assemblies, they’re bursting with features such as autofocus, optical stabilization and zoom. [Saulius Lukse] has been experimenting with motorized lenses for webcam applications, and has built a controller to make working with them a snap.

The controller is capable of controlling up to 3 stepper motors, as well as a voice coil, which should be enough for the vast majority of lenses out there. Microstepping is supported, which is key for optical systems in which tiny adjustments can make a big difference. The controller speaks USB and I2C, and is now based on an STM32 chip, having been upgraded from an earlier version which used the venerable ATmega328. The board is designed to be as compact as possible, to enable it to neatly fit inside camera and lens assemblies.

The board has been used to successfully control an 18x zoom lens, among others. Combining such a lens with a webcam and a good pan and tilt mechanism would create a highly capable surveillance package, or an excellent vision system for a robot.

It’s not the first time we’ve seen work from [Kurokesu] in these parts – they’ve done work on pedestrian detection before, too.

Four Chips To Retro Perfection

July 10, 2019 by 24 Comments

Over the years, we’ve seen many people build a computer from the ground up. It’s always great, but this one takes the cake. I’m not just saying that because there’s a cute little ‘Z80 Inside’ logo on the silk screen, either. It’s a four IC Z80 computer, a tiny board, and [Just4Fun]’s entry into this year’s Hackaday Prize.

This single board computer is only four chips, the most important being the CMOS Z80 CPU. This is the same CPU as was found in the TRS-80 and the ZX Spectrum, both classics from the early days of computing. In addition to the PCU, there’s a Toshiba SRAM with 128 whole kilobytes of random access memories. A 74HC00 is thrown into the mix for glue logic, and everything else happens through a specially-programmed ATMega32A. This last chip provides a universal I/O subsystem, the EEPROM, and the 4/8MHz clock for the CPU.

Those four chips are really all you need for a fully functional computer, but you can do so much more with this little board. There’s a uCom board, or basically a ‘transparent’ USB-to-serial emulator that will allow you to upload a hex file to the board. Of course this means you can also connect it to a terminal, and with FuzixOS, there’s Unix for the Z80. It’s a wonderment of retrocomputing, and one of the best ways to build an old computer today.

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