Synth Gains Plug And Play Analog MUX

May 4, 2021 by 3 Comments

High school computer engineering teacher [Andy Birch] kept losing track of I/O pins on his home-built synth, so he made a custom plug and play addressable MUX system to solve the problem. [Andy]’s synth is based on the Teensy microcontroller, and he was already using CMOS analog 8:1 multiplexer chips (CD4051) to give him more I/O pins. But I/O pin expansion means that now there are more I/O pins to forget. Did I hook up that pitch potentiometer on U3 pin 13 or was it U10 pin 2?

He proceeds to design an addressing system for each I/O card using three bits (expandable to four) supporting eight cards, with a maximum of 16 possible in the future. Since each card may not use all eight signals, each card can tell the Teensy how many signals it has. [Andy] does his address decoding on each card using OR and XOR gates. We would have considered using a single 74HC85 four-bit magnitude comparator instead. That would require only one chip instead of two, but would deprive his students of the opportunity to learn gate level address decoding.

When seeing the term “I/O card”, you may be fooled like we were into thinking this was using PCBs and some kind of motherboard. [Andy]’s I/O cards are actually solderless breadboards mounted on the back of the synth control panel. We really like his bus technique — he removes the power strip sections from several breadboards and repurposes them as address and data buses. Check out the thorough documentation that [Andy] has prepared, and let us know if you have ever designed your own plug and play method for a project in the comments below.

[Ed Note: We love us some muxes!]

I/O Cards — Note the use of Power Strip Bars as Data / Address Buses

 

Linux Fu: Mixing Bash And Python

May 4, 2021 by 24 Comments

Although bash scripts are regularly maligned, they do have a certain simplicity and ease of creation that makes them hard to resist. But sometimes you really need to do some heavy lifting in another language. I’ll talk about Python, but actually, you can use many different languages with this technique, although you might need a little adaptation, depending on your language of choice.

Of course, you don’t have to do anything special to call another program from a bash script. After all, that’s what it’s mainly used for: calling other programs. However, it isn’t very handy to have your script spread out over multiple files. They can get out of sync and if you want to send it to someone or another machine, you have to remember what to get. It is nicer to have everything in one file.

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New Contest: Reinvented Retro

May 4, 2021 by 22 Comments

There are so many ways to make things look awesome by pulling inspiration from great retro hardware. And combining today’s futuristic functionality with yesterday’s lines, colors, and kitsch is the quick path to a winning combination. So why not give it a try and show us what you got? That’s the gist of Hackaday’s Reinvented Retro Contest which begins right now and runs through June.

The is a very cool Roku

This smart TV should help get you thinking in a retro-modern way. You’d never know it wasn’t stock… except when it starts streaming The Falcon and the Winter Soldier via the Roku hidden inside. Fit and finish on this one is spectacular and that woodgrain remote is a piece of artwork!

So what will it be? Keurig in a 1960’s Perculator? Desk lamp in a rotary telephone? GHz oscilloscope where a CRT used to live? Perhaps a Raspberry Pi laptop in a 1990’s form-factor? You get to decide what “Retro” means, just make sure you thoroughly show off the build!

Digi-Key is sponsoring this contest and there are $200 shopping sprees from their warehouse up for grabs for each of three top winners. Make a project page over on Hackaday.io and use the “Submit project to…” dropdown in the left side bar to enter it in the Reinventing Retro Contest.

Feel What The Temperature Is Like Outside Without Leaving Your Bed

May 4, 2021 by 17 Comments

Your smartphone might be able to tell you what the weather is like outside, but you’d have to go outside yourself to really feel it. To do this from the comfort of your own bed, [Sagarrabanana] built a clock that lets you really feel the temperature. Video below with English subtitles.

It is basically a box with a solenoid inside to knock out the time, and a Peltier plate on top. Give the box two knocks, which are detected by a piezo element,  and it will tell you the current time down to 15 minute increments in “bell tower” format. Give it three knocks, and the ESP8266 will fetch the ambient outside temperature from a cloud service and cool or heat the Peltier element to that temperature, using a H-bridge motor driver module. The code and design files are available on GitHub if you want to build your own.

All the components are housed inside an attractive 3D printed box with a machined wood top. Although we think this is a very interesting idea, we can’t help but suspect that it might be counterproductive for getting you out of bed on those cold winter mornings.

While alarm clocks are falling out of favor, they are still a popular build for hackers. We’ve covered one that looks like it came from a fallout shelter, and another with a very cool looking VFD display. Continue reading “Feel What The Temperature Is Like Outside Without Leaving Your Bed” →

TypeMatrix EZ-Reach 2030 Is Better Than Your Laptop Keyboard

May 4, 2021 by 38 Comments

Maybe you’re not ready to take the leap into a full-on ergonomic split keyboard. That’s okay, that’s cool, that’s understandable. They’re weird! Especially ones like my Kinesis Advantage with the key bowls and such. But maybe your poor pinkies are starting to get tired and you’re ready to start using your thumbs for more than just the space bar. Or you want to be able to type ‘c’ properly, with your middle finger.

In that case, the TypeMatrix could be the keyboard for you. Or maybe for travel you, because it’s designed as a quasi-ergonomic, orthonormal layout travel keyboard to pair with your laptop, and as such it sits directly over a laptop keyboard without blocking the track pad. (How do people use those things, anyway?)

Of course, you could use this as a desktop keyboard as well, although it’s unfortunate that Control and Shift are stuck on the pinkies. More about that later.

First Impressions

When I saw this keyboard on eBay, I was attracted by two things: the layout, and the dedicated Dvorak light. (And, let’s be honest — the price was right.) I’ve always found myself generally turned off by chocolate bar-style ortholinear keebs because they’re so incredibly cramped, but this one seemed a more acceptable because of the slight split.

The first thing I noticed was the fantastic number pad integration. The different colored keycaps are a nice touch, because the gray makes the number pad stand out, and the red Delete is easy to find since Num Lock is squatting in the upper right corner. Why does Delete always feel like an afterthought on compact keebs? I also like the location of the arrows, and it makes me think of the AlphaSmart NEO layout. Unfortunately, it comes at the cost of burying the right hand Enter down in no-man’s land where you can’t exactly hit it blindly with great accuracy right away. If only you could swap Shift and Enter without messing up the number pad!

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Soviet Super 8 Camera Hides Raspberry Pi Zero

May 4, 2021 by 14 Comments

A few years ago [Xabier Zubizarreta] got it into his head that he wanted to put a modern digital image sensor into a classic Super 8 camera, but he didn’t want to ruin a gorgeous piece of vintage hardware in the process. After a bit of research, he discovered an export version of the Avrora camera made for the 1980 Summer Olympic Games in Moscow that could be had for cheap. Figuring nobody would miss a camera built with the utilitarian aesthetics you’d expect of a Soviet-era piece of consumer tech, he set off to cram a Raspberry Pi into its film compartment.

On the Hackaday.io page for this project, [Xabier] explains a bit about the optical properties that make this project challenging. Specifically, the miniature sensor used by the official Raspberry Pi camera module is far smaller than the 8 mm film the camera was designed for. So when the sensor placed at the appropriate focal length for the original film, the image will be cropped considerably. As you can see in the video below, this gives the impression of everything being filmed with a fairly tight zoom.

To perform this modification, [Xabier] first had to liberate the sensor of the Pi Camera from the original optics, and then carefully install it in proper position on the Avrora. To make sure he had it aligned, he watched a live feed from the camera while the epoxy holding the sensor down was curing. This allowed him to make slight adjustments before everything was solidified. With the sensor in place, he only had to stuff the Pi Zero and battery pack into the film compartment, and wire the original camera trigger to the GPIO pins so he could read it in software.

Considering the incredible amount of effort some photographers have put in to adapt their vintage cameras to digital, it’s refreshing to see such a straightforward approach. The resulting video might not be up to modern standards, but with projects like this, that’s sort of the point.

Continue reading “Soviet Super 8 Camera Hides Raspberry Pi Zero” →

Enjoy An ASCII Version Of Star Wars In The Palm Of Your Hand For May The 4th

May 4, 2021 by 13 Comments

Everyone by now has probably seen the original — and best; fight us — installment of the Star Wars franchise, and likely the ASCII-art animation version of it that improves greatly on the film by eliminating all those distracting special effects, human actors, and the soundtrack. But what we haven’t had until now is a portable player for ASCIIWars, to enjoy the film in all its character-based glory while you’re on the go.

While this tribute to [Simon Jansen]’s amazing ASCII-art achievement might seem like a simple repackaging of the original, [Frank] actually had to go to some lengths to make this work. After getting [Simon]’s blessing, the build started with a WEMOS D1 Mini, a good platform for the project less for its wireless capabilities and more for its 4 MB of flash memory. A 240×360 TFT LCD display was selected to show the film; the scale of the display made most fonts hard to read, so [Frank] used Picopixel, a font designed for legibility on small screens. The animation file is stored on the SPIFFS file system on the D1’s flash memory, and a few lines of code parse it and send it to the display. The final touch is mounting the whole thing is an old slide viewer, which magnifies the display to make it a little easier to see.

As much as we applaud [Frank]’s tribute to [Simon]’s effort, there’s no reason to confine this to the Star Wars universe. If you read up on the history of ASCII art, which goes surprisingly far back, you might be inspired to render another classic film in ASCIImation and put it on a viewer like this. ASCII-Metropolis, anyone?

Continue reading “Enjoy An ASCII Version Of Star Wars In The Palm Of Your Hand For May The 4th” →