Prophet 600: A Classic Synthesizer Gets Processor Upgrade


We love classic synthesizers here at Hackaday. So does [gligli], but he didn’t like the processor limitations of the Prophet 600. That’s why he’s given it a new brain in the form of a Teensy++. The Sequential Circuits Prophet 600 was a big deal when it was released back in 1982/1983. The 600 was the first commercially available synthesizer to include a MIDI interface. The original design of the 600 could be called a hybrid. A Zilog Z80 microprocessor controlled modular analog voice chips. The Z80 was a bit stressed in this configuration though, and a few limitations were evident. An 8 bit processor just wasn’t quite enough for software driven envelopes and a Low Frequency Oscillator (LFO) control. This was further exacerbated by the fact that everything was driven through a 14 bit DAC.

[gligli] discovered most of the limitations in the 600 were due to the processor. By beefing up the processing power he could really unlock the potential within 600. Since he didn’t actually have a Prophet 600, he started with the schematic. [gligli] created a PC based emulator for the digital circuits, learning the whole system as he worked. With that phase complete, [gligli] bought a used Prophet and started hacking. The Teensy++ required a few hardware mods to fill the Z80’s shoes, including cutting off a pin and adding a few jumper wires. We really like the fact that no changes to the Prophet 600 itself are required. Pull out the Teensy++, drop in the Z80, and you’re ready to party like it’s 1982 again.

The new processor interfaces directly with the Z80’s 8 bit bus. Since the AVR on the Teensy has built-in RAM and ROM, it simply ignores the ROM and RAM address spaces of the original system. Interfacing a fast micro with older parts like an 8253 timer and a 68B50 UART does have its pitfalls though. The system bus had to run slow enough to not violate timing requirements of the various peripheral chips. To handle this, [gligli] added a number of wait statements in his firmware. Once the system was working, [gligli] was free to start adding new features. He began by smoothing out the stepped envelope and filter generators, as well as adding new exponential modes. From there he added new keyboard polyphony modes as well as pitch and mod wheel changes. The full lineup of new features are listed in the instruction manual (PDF link). Since this is an open source project, adding a feature is as simple as cracking open your favorite editor and writing it up.

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Homemade Ball Mill Tumbles Along Like a Champ

[Mike] enjoys doing all kinds of things with glass. He likes to melt it and fuse it into new things, so it’s perfectly understandable that he wanted to make his own glass. Doing so requires finely ground chemicals, so [Mike] put together this awesome homemade ball mill.

The design is wonderfully simple. The mill is powered by a robust 12VDC motor from a printer that he’s running from a variable power supply in order to fine tune the speed. [Mike] built a scrap wood platform and attached four casters for the drum to spin against. The drum is rotated by a round belt he had lying around from various other projects. [Mike] already had a couple of those blue containers, which formerly held abrasive grit for use in vibratory tumblers.

[Mike] had some trouble with the drum walking off the casters so he attached scrap piece of aluminum to form an end stop. All he had to buy for this project were the 5/8″ steel balls and the casters. The mill can also be used as a rock tumbler, though the bottle isn’t quite water tight as-is. He does not recommend this type of setup for milling gunpowder or other explosives, and neither do we.

Make the jump to see the mill in action and get the grand tour. If you need more tumbling power, use a dryer motor!

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We Asked For It — An Arduino Bowel Gauge


Well, we asked for it, and [TV Miller] delivered this hilarious and surprisingly accurate bowel gauge.

Between our recent Wiping Your Bum with an Arduino feature and how to Measure Poop for a Better Sanitation Service, we guess we should have seen this coming. And you know what? It’s pretty awesome.

He’s using an Arduino Uno with a home-made resistance sensor to “hack our bowels”. After all, how can you have a proper diet without knowing exactly what is coming out of you? Two copper or aluminum strips make up the resistance sensor with a few known resistors, a capacitor and a potentiometer for adjustment. He’s even included an LCD display as well so you can see the volume of your excrement in real-time! Classy.

To see it in action (don’t worry, not that kind of action) stick around for the following video:

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Hackaday in Shanghai: Electronica and a Gathering


Whether you live in Shanghai, are at Electronics China representing your company, or by dumb luck just happen to be in town this week you can meet some of the Hackaday crew and score yourself some sweet swag.

Anyone in town on Thursday night will want to get a ticket to Hackaday: The Gathering. Right now it’s all sold out, but we hope anyone with a ticket who is unable to use it will cancel so that another may take your place. Free food, drink, t-shirts, stickers, and other swag await… no wonder the tickets are already gone!

The Electronica China conference started Tuesday at Shanghai New International Expo Centre, but it runs through Wednesday and Thursday as well. We’re attending, but we don’t actually have a dedicated booth. Hackaday is piggybacking with EEFocus, the Chinese contingent of our parent company. Both [Matt] and [Alek] will be hanging around the EEFocus booth (#W3.3686) shucking out hackaday T-shirts if you ask for one. Before he left, [Matt] mentioned that he’s excited to attend lectures on connected medical devices, the Automotive and EV boards, as well as the embedded systems forum.


MRRF: 3D Bioprinting


There were a few keynotes at this year’s Midwest RepRap festival, and somewhat surprisingly most of the talks weren’t given by the people responsible for designing your favorite printer. One of the most interesting talks was given by [Jordan Miller], [Andy Ta], and [Steve Kelly] about the use of RepRap and other 3D printing technologies in biotechnology and tissue engineering. Yep, in 50 years when you need a vital organ printed, this is where it’ll come from.

[Jordan] got his start with tissue engineering and 3D printing with his work in printing three-dimensional sugar lattices that could be embedded in a culture medium and then dissolved. The holes left over from the sugar became the vasculature and capillaries that feed a cell culture. The astonishing success of his project and the maker culture prompted him and others to start the Advanced Manufacturing Research Institute to bring young makers into the scientific community. It’s a program hosted by Rice University and has seen an amazing amount of success in both research and getting makers into scientific pursuits.

One of these young makers is [Andy Ta]. An economics major, [Andy] first heard of the maker and RepRap community a few years ago and bought a MakerBot Cupcake. This was a terrible printer, but it did get him involved in the community, hosting build workshops, and looking into 3D printing build around DLP-cured UV resin. At AMRI, [Andy] started looking at the properties of UV-cured resin, figuring out the right type of light, resin, and exposure to create a cured resin with the right properties for printing cell colonies. You can check out [Andy]‘s latest work on his webzone.

[Steve Kelly] has also done some work at AMRI, but instead of the usual RepRap or DLP projector-based printers, he did work with shooting cell cultures out of an ink jet print head. His initial experiments involved simply refilling an ink jet cartridge with a bacterial colony and discovering the cells actually survived the process of being heated and shot out of a nozzle at high speed. Most ink jets printers don’t actually lay out different colors on a precise grid, making it unusable for growing cell cultures. [Steve] solved this problem with an inkjet controller shield attached to a RepRap. All of [Steve]‘s work is documented on his Github.

It’s all awesome work, and the beginnings of both bioengineering based on 3D printers, and an amazing example of what amateur scientists and professional makers can do when they put their heads together. Video link below.

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Retrotechtacular: Breaking Atoms to Break the Ice


This documentary from 1959 gives a satisfyingly thorough look inside a nuclear powered icebreaking ship called Lenin. This actually set a couple of world’s-firsts: it was the first nuclear powered surface vessel and the first civilian vessel to be powered thusly.

The ship was built to clear shipping paths to the northern ports of Russia. Testing of both ice and models of the ship design point to the ability to break ice layers that are two meters thick. This requires a lot of power as ice-breakers generally use their hull shape and gravity to break the ice by driving up onto it to bend the ice to the breaking point. The Lenin achieved this power using its nuclear reactor to heat steam which drove electric generators. The energy produced drove three screws to power the vessel.

Of course this was back in the day when control panels were substantial, which you can get a peek at starting half-way through the twenty-minute film. This includes a demonstration of the ship’s network of radiation sensors which alert the control room, and sound a local alarm when they are triggered. During it’s 30-year operational life the vessel had a couple of accidents stemming from refueling operations. You can find more on that over at the Wikipedia page, but stick with us after the jump to see the vintage reel.

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From Saw Dust to Stove Fuel

brisquit maker

[Alois Schmid] is an avid woodworker, and as such, he makes a lot of saw dust. Unfortunately, saw dust is kind of wasteful — it doesn’t burn very well unless it is compressed… so he built his own wood briquette press!

He originally looked at purchasing a machine designed for this, until he discovered they run upwards of 10,000 Euros. You could buy an amazing CNC mill for that! Needless to say, it was out of the question.

He started by purchasing a new more efficient dust extractor and an electric log splitter, and then he built an ingenious feeder system. He’s replaced the log splitter blade with a long metal dowel with a protrusion at the end (helps keeps the briquettes in one piece), which is slightly smaller than the compression tube he’s built.

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