Oh Baby, Baby10 – Build A Classic Analog Music Sequencer

January 14, 2016 by Nava Whiteford 20 Comments

Recently I’ve been learning more about classic analog music synthesizers and sequencers. This has led me to the Baby10, a classic and simple analog sequencer design. In this article I’ll introduce its basic operation, and the builds of some awesome hackers based on this design.

Sequencers produce, a sequence of varying voltages. These control voltages (CV) can then be use to control other components. Often this is a simple tone generator. While the concept is simple, it can produce awesome results:

A basic sequencer is a great beginners project. It’s easy to understand the basic operation of the circuit and produces a satisfyingly entertaining result. The Baby 10 was originally published in a column called “Captain’s Analog”, but has now been widely shared online.

The circuit uses the 4017, a simple CMOS decade counter. The 4017 takes an input clock signal then sequentially outputs a high pulse on each of 10 output pins. As such, the 4017 does almost everything we need from a sequencer in a single IC! However, we want our sequencer to output a varying voltage which we can then use to generate differing tones.

To accomplish this variable resistors are connected to each of the output pins. A diode in series with the variable resistor stops the outputs fighting against each other (in layman’s terms).

To make the sequencer more visually attractive (and give some feedback) LEDs are often also added to the output of the 4017. A complete Baby 10 sequencer is shown in the schematic below. The original circuit used 1N917s, these are no longer available but the part has been replaced by the 1N4148.

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PS/2 Keyboard For Raspberry Pi

January 14, 2016 by Al Williams 29 Comments

A lot of people can bake a cake. Sort of. Most of us can bake a cake if we have a cake mix. Making a cake from scratch is a different proposition. Sure, you know it is possible, but in real life, most of us just get a box of cake mix. The Raspberry Pi isn’t a cake (or even a pie), but you could make the same observation about it. You know the Raspberry Pi is just an ARM computer, you could program it without running an available operating system, but realistically you won’t. This is what makes it fun to watch those that are taking on this challenge.

[Deater] is writing his own Pi operating system and he faced a daunting problem: keyboard input. Usually, you plug a USB keyboard into the Pi (or a hub connected to the Pi). But this only works because of the Linux USB stack and drivers exist. That’s a lot of code to get working just to get simple keyboard input working for testing and debugging. That’s why [Deater] created a PS/2 keyboard interface for the Pi.

Even if you aren’t writing your own OS, you might find it useful to use a PS/2 keyboard to free up a USB port, or maybe you want to connect that beautiful Model-M keyboard without a USB adapter. The PS/2 keyboard uses a relatively simple clock and data protocol that is well-understood. The only real issue is converting the 5V PS/2 signals to 3.3V for the Pi (and vice versa, of course).

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3D Printing Metal From Rust

January 14, 2016 by Elliot Williams 25 Comments

It seems backwards, but engineers from Northwestern University have made 3D printing metal easier (and eventually cheaper) by adding extra production steps to the procedure. (Paper available in PDF).

Laser sintering works by laying down a thin layer of metal powder and then hitting it with a strong enough laser to sinter the particles together. (Sintering sticks the grains together without getting the metal hot enough to melt it.) The rapid local heating and cooling required to build up 3D objects expands and cools the metal, and can result in stresses inside the resulting object.

The Northwestern team still lays down layers of powder, but glues the layers together with a quick-drying polymer instead of fusing them with a laser. Once the full model is printed, they then sinter it in one piece in an oven.

anewwaytopri_tn — 3D-printed copper lattice. Credit: Ramille Shah and David Dunand

The advantages of adding this extra step are higher printing speed — squirting the liquid out of syringe heads can be faster than fusing metal particles with a laser — and increased structural integrity because the whole model is heated and cooled at one time. A fringe benefit is that the model is still a bit flexible before firing, opening up possibilities for printing a flat model and then bending it into shape before sintering.

And if that weren’t enough, the team figured that they’d add a third step to the procedure to allow it to be used with rust (iron oxide) as the starting powder. They print the rust and polymer model, then un-rust the iron using hydrogen, and then fire it as before. Why rust? Do you know anything cheaper to use as a raw material?

What do you think? The basic idea may even be DIYable — glue metal particles together and heat them up enough to stick. Not in my microwave oven, though. We’d love to see a more energy-efficient 3D metal printer.

Thanks to [Joe] for the tip!

Cheap Smartwatch Teardown

January 13, 2016 by Al Williams 31 Comments

A proper smartwatch can cost quite a bit of money. However, there are some cheap Bluetooth-connected watches that offer basic functions like show your incoming calls, dial numbers and display the state of your phone battery. Not much, but these watches often sell for under $20, so you shouldn’t expect too much.

Because they’re so cheap, [Lee] bought one of these (a U8Plus) and within an hour he had the case opened up and his camera ready. As you might expect, the biggest piece within was the rechargeable battery. A MediaTek MT6261 system on a chip provides the smart part of the watch.

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Nanotech Makes Safer Lithium Batteries

January 13, 2016 by Al Williams 11 Comments

Lithium-ion batteries typically contain two electrodes and an electrolyte. Shorting or overcharging the battery makes it generate heat. If the temperature reaches about 300 degrees Fahrenheit (150 degrees Celsius), the electrolyte can catch fire and explode.

There have been several attempts to make safer lithium-ion cells, but often these safety measures render them unusable after overheating. Stanford University researchers have a new method to protect from overheating cells that uses–what else–nanotechnology graphene. The trick is a thin film of polyethylene that contains tiny nickel spikes coated with graphene (see electron micrograph to the right).

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Microchip’s Proposal To Acquire Atmel

January 13, 2016 by Brian Benchoff 130 Comments

A proposal from Microchip to acquire Atmel has been deemed a ‘superior proposal’ by Atmel’s board of directors (PDF). This is the first step in the acquisition of a merger between Microchip and Atmel, both leading semiconductor companies that have had a tremendous impact in the electronics industry.

Microchip is a leading manufacturer of microcontrollers, most famously the PIC series of micros that can be found in any and every type of electronic device. Atmel, likewise, also has a large portfolio of microcontrollers and memory devices that are found in every type of electronic device. Engineers, hackers, and electronic hobbyists are frequently sided with Microchip’s PIC line or Atmel’s AVR line of microcontrollers. It’s the closest thing we have to a holy war in electronics.

Last September, Dialog ~~acquired~~ announced plans to acquire Atmel for $4.6 Billion. Today’s news of a possible acquisition of Atmel by Microchip follows even larger mergers such as NXP and Freescale, Intel and Altera, Avago and Broadcom, On Semiconductor and Fairchild, and TI and Maxim. The semiconductor industry has cash on hand and costs to cut, these mergers and acquisitions are the natural order of things.

While the deal is not done, the money is on the table, and Atmel’s board is apparently interested.

Decoding Data Hiding In Star Trek IV

January 13, 2016 by Adam Fabio 40 Comments

1986: The US and Russia signed arms agreements, Argentina won the world cup, and Star Trek IV: The Voyage Home hit the theaters. Trekkies and the general public alike enjoyed the film. Some astute hams though, noticed a strange phenomenon about halfway through the film. During a pivotal scene, Scotty attempts to beam Chekov and Uhura off the Enterprise, but has trouble with interference. The interference can be heard over the ubiquitous Star Trek comm link. To many it may sound like random radio noise. To the trained ear of a [Harold Price, NK6K] though, it sounded a heck of a lot like packet radio transmissions.

By 1989, the film was out on VHS and laser disc. With high quality audio available, [Harold] challenged his friend [Bob McGwier, N4HY] to decode the signal. [Bob] used the best computer he had available: His brain. He also had a bit of help from a Cray 2 supercomputer.

[Bob] didn’t own his own Cray 2 of course, this particular computer was property of the National Security Agency (NSA). He received permission to test Frequency Shift Keyed (FSK) decoder algorithms. Can you guess what his test dataset was?

The signal required a lot of cleanup: The original receiver was tuned 900 Hz below the transmission frequency. There also was a ton of noise. To make matters worse, Scotty kept speaking over the audio. Thankfully, AX.25 is a forgiving protocol. [Bob] persevered and was able to obtain some usable data. The signal turned out to be [Bill Harrigill, WA8ZCN] sending a Receive Ready (RR) packet to N6AEZ on 20 meters. An RR packet indicates that [Bill’s] station had received all previous packets and was ready for more. [Bob] called to [Bill], who was able to verify that it was probably him transmitting in the 1985 or 1986, around the time the sound editors would have been looking for effects.

That’s a pretty amazing accomplishment, especially considering it was 1989. Today, we carry supercomputers around in our pockets. The Cray 2 is roughly equivalent to an iPhone 4 in processing power. Modern laptop and desktop machines easily out class Seymour Cray’s machine. We also have software like GNU Radio, which is designed to decode data. Our challenge to you, the best readers in the world, is to replicate [Bob McGwier’s] work, and share your results.