Hackaday Links: October 11, 2015

[Kratz] just turned into a rock hound and has a bunch of rocks from Montana that need tumbling. This requires a rock tumbler, and why build a rock tumbler when you can just rip apart an old inkjet printer? It’s one of those builds that document themselves, with the only other necessary parts being a Pizza Hut thermos from the 80s and a bunch of grit.

Boot a Raspberry Pi from a USB stick. You can’t actually do that. On every Raspberry Pi, there needs to be a boot partition on the SD card. However, there’s no limitation on where the OS resides,  and [Jonathan] has all the steps to replicate this build spelled out.

Some guys in Norway built a 3D printer controller based on the BeagleBone. The Replicape is now in its second hardware revision, and they’re doing some interesting things this time around. The stepper drivers are the ‘quiet’ Trinamic chips, and there’s support for inductive sensors, more fans, and servo control.

Looking for one of those ‘router chipsets on a single board’? Here you go. It’s the NixCoreX1, and it’s pretty much a small WiFi router on a single board.

[Mowry] designed a synthesizer. This synth has four-voice polyphony, 12 waveforms, ADSR envelopes, a rudimentary sequencer, and fits inside an Altoids tin. The software is based on The Synth, but [Mowry] did come up with a pretty cool project here.

Hackaday Links: September 20, 2015

Here’s an offer from Intel and the guy behind all of reality TV [Mark Burnett]: win a million dollars for making something. Pitch an idea for wearable electronics to the producers by October 2, and you might be on a reality TV show about building electronics which they’re calling America’s Greatest Makers. With this, Intel is promoting the Curie module a tiny, tiny SoC with Bluetooth, IMU, and DSP functions. We’re of the opinion that a Hackaday reader should win this contest, or at the very least be featured prominently in the show. No, it’s not Junkyard Wars, but it’s still a million dollar prize.

[Jeremy] builds bombs clocks, and he has a Kickstarter for an interesting Nixie clock. Most Nixie tubes have digits, but [Jeremy] is using the IN-9 ‘bar’ tubes for the hour and minute hand.

The Luka EV is a semifinalist for the Hackaday Prize, and a completely open, road legal electric vehicle powered by hub motors. It also looks really, really cool.  Now, they’re selling them. It’s €20,000 for a complete car. Did I mention how cool it looks?

Boca Bearings is having a ‘Show Us Your Workshop’ contest, with the best (or should it be worst?) workshop winning tool cabinets, tool kits, a work mat, and calipers.

The EMU Drumulator is a classic drum machine that featured dirty 12-bit drum sounds in ROM. Now, it’s a single chip thanks to [Jan]. He’s done a lot of great work putting synths in single chips, and it’s great to see him move on to classic drum machines.

Offered without comment, here’s a ride through a PCB.

The Ubiquitous Atari Punk Console

The Atari Punk Console (APC) is a dual 555 (or single 556) based synth. Designed by the famous (and somewhat infamous) Forrest Mims in 1980 and originally simply named “Sound Synthesizer”, the circuit gained it’s more recent popularity when re-dubbed the “Atari Punk Console” by Kaustic Machines. The circuit however doesn’t bear much relation to the Atari 2600 which didn’t contain a 555 timer chip. However we assume the 2600 produced a similarly glitchy square wave audio output.

a2The circuits operation is easy to grasp and uses only 9 components. This ease of design and construction has allowed builders to focus more on the aesthetics of its construction, hacking it into interesting, and often unlikely enclosures and systems. One such hack is the “Atari Punk Bucket” (shown here) where the APC along with a simple amp was hacked into an old rusted bucket. The APC was built up on strip-board along with a simple amp and reclaimed speakers. [Farmer glitch] has used this as a prop in live sets and it both looks and sounds awesome. Continue reading “The Ubiquitous Atari Punk Console”

The Kraakdoos — Musical Abuser of an Ancient OpAmp

A friend from the newly founded Yeovil Hackerspace introduced me to a device known as “The Kraakdoos” or cracklebox.

The cracklebox is an early electronic instrument produced by STEIM in the 1970s. The instrument consists of a single PCB with a number of copper pads exposed on one side. The player touches the pads and the instrument emits… sounds which can perhaps best be described as squeeze and squeals.

While the cracklebox was original sold as a complete instrument, the device has been reverse engineered, and the schematic documented. What lies inside is quite fascinating.

The heart of the cracklebox is an ancient opamp, the LM709. The LM709 is the predecessor to the famous LM741. Unlike the 741 the 709 had no internal frequency compensation. Frequency compensation is used to intentionally limit the bandwidth of an opamp. As input frequency increases, the phase shift of the opamp also increases. This can result in undesirable oscillation, as the feedback network forms an unintentional phase-shift oscillator.

Most modern opamps have internal frequency compensation, but the 709 doesn’t. Let’s see how this is used in the cracklebox:

krackdoos_schRather than using the frequency compensation pins as intended the cracklebox just routes them out to pads. In fact the cracklebox routes almost all the pins on the opamp out to pads, including the inverting and non-inverting inputs. A single 1MOhm feedback resistor is used in a non-inverting configuration. However reports suggest the instrument can work without a feedback resistor at all!

Continue reading “The Kraakdoos — Musical Abuser of an Ancient OpAmp”

Hackaday Links: July 19, 2015

Everybody needs an external USB drive at some time or another. If you’re looking for something with the nerd cred you so desperately need, build a 5 1/4″ half height external drive. That’s a mod to an old Quantum Bigfoot drive, and also serves as a pretty good teardown video for this piece of old tech.

The Woxun KG-UV2D and KG-UV3D are pretty good radios, but a lot of amateur radio operators have found these little handheld radios eventually wear out. The faulty part is always a 24C64 Flash chip, and [Shane] is here to show you the repair.

Last year there was a hackathon to build a breast pump that doesn’t suck in both the literal and figurative sense. The winner of the hackathon created a compression-based pump that is completely different from the traditional suction-based mechanism. Now they’re ready for clinical trials, and that means money. A lot of money. For that, they’re turning to Kickstarter.

What you really need is head mounted controls for Battlefield 4. According to [outgoingbot] it’s a hacked Dualshock 4 controller taped to a bike helmet. The helmet-mounted controller has a few leads going to another Dualshock 4 controller with analog sticks. This video starts off by showing the setup.

[Jan] built a modeling MIDI synth around a tiny 8-pin ARM microcontroller.  Despite the low part count, it sounds pretty good. Now he’s turned his attention to the Arduino. This is a much harder programming problem, but it’s still possible to build a good synth with no DAC or PWM.

Hackaday Prize Entry: 3D Printed Modular Keyboard

There is a big community of people creating all kinds of synthesizers, but until now no one has attempted to make a keyboard controller like the one [Tim] created. Not only has he created the keyboard synthesizer, but he’s developed one that is modular and 3D printed so you can just expand on the synth you have rather than go out and buy or build a new one.

The design has a lot useful features. Since the design is modular, you can 3D print extra octaves of keys if you need, and simply build off of the existing keyboard. The interior has mounts that allow circuit boards to be screwed down, and the exterior has plenty of available places to put knobs or sliders. Anything that could possibly be built into a synthesizer is possible with this system, and if you decide you want to start small, that’s possible too!

All of the design files are available from Pinshape if you want to get started. The great thing about this controller is that you could use a 555-based synth in this keyboard controller, or a SID synth, or any other synth you could think of!

The 2015 Hackaday Prize is sponsored by:

Busted Wah Pedal Becomes New Synth Tool

Sometimes we get lucky and find a part we need for a project in our parts drawer. [Scissorfeind] got even luckier and found a part for his project lying around in the street. It was a Crybaby Wah pedal, a classic effects pedal typically used for a guitar. Since it was somewhat damaged, [Scissorfeind] got to work creating a control voltage (CV) and volume circuit for his Korg synthesizer.

For those who aren’t synthesizer aficionados, CV is a method of controlling the pitch of a tone. A higher voltage creates a higher tone and vice-versa. The wah pedal has a rocker on it that allows one’s foot to control the effect, but this particular one has been modified for CV instead of the wah-wah sound these pedals normally make. [Scissorfeind] built in a switch that will allow it to control volume as well, which makes this pedal quite unique in the effects world.

[Scissorfeind] built the custom circuit out of other parts he had lying around (presumably not in the street) and put the entire thing together on perfboard, then fit it all back together in the pedal. Now he has a great control voltage pedal for the vintage Korg synthesizer he recently restored! [Scissorfeind] knows his way around a synth, but if you’re looking to get started on a synthesizer project we have a great tutorial for you!