MicroVox Puts The 80’s Back Into Your Computer’s Voice

February 22, 2017 by Steven Dufresne 22 Comments

[Monta Elkins] got it in his mind that he wanted to try out an old-style speech synthesizer with the SC-01 (or SC-01A) chip, one that uses phonemes to produce speech. After searching online he found a MicroVox text-to-speech synthesizer from the 1980s based around the chip, and after putting together a makeshift serial cable, he connected it up to an Arduino Uno and tried it out. It has that 8-bit artificial voice that many of us remember fondly and is fairly understandable.

The SC-01, and then the SC-01A, were made by Votrax International, Inc. In addition to the MicroVox, the SC-01 and SC-01A were used in the Heath Hero robot, the VS-100 synthesizer add-on for TRS-80s, various arcade games such as Qbert and Krull, and in a variety of other products. Its input determines which phonemes to play and where it shines is in producing good transitions between them to come up with decent speech, much better than you’d get if you just play the phonemes one after the other.

The MicroVox has a 25-pin RS-232 serial port as well as a parallel port and a speaker jack. In addition to the SC-01A, it has a 6502 under the hood. [Monta] was lucky to also receive the manual, and what a manual it is! In addition to a list of the supported phonemes and words, it also contains the schematics, parts list and details for the serial port which alone would make for fun reading. We really liked the taped-in note seen in this screenshot. It has a hand-written noted that says “Factory Corrected 10/18/82”.

Following along with [Monta] in the video below, he finds the serial port’s input buffer chip datasheet online and verifies the voltage levels. Next he opens up the case and uses dips switches to set baud rate, data bits, parity, stop bits and so on. After hooking up the speakers, putting together a makeshift cable for RX, TX and ground, and writing a little Arduino code, he sends it text and out comes the speech.

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Interview: Nacer Chahat Designs Antennas For Mars CubeSats

February 22, 2017 by Mike Szczys 31 Comments

You have a shoe box sized computer that you want to use in a Mars fly by. How do you communicate with it? The answer is a very clever set of antennas. I got to sit down with Nacer Chahat, one of the engineers on the Jet Propulsion Laboratory team responsible for antenna design on Mars Cube One (MarCO). Two of these CubeSats that will soon be used to help a lander reach Mars. We talked about the work that went into MarCO, the deployable radar antenna he’s worked on for the RainCube project, and the early progress on OMERA, the One Meter Reflectarray.

This is a fascinating discussion of dealing with a multitude of engineering challenges including lack of available space for the antenna components, and power and weight limitations. Check out the video interview to see how the people at JPL fit it all into this, and other tiny satellites, then join us below for more details.

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T-Rex Runner Runs On Transistor Tester

February 22, 2017 by Anool Mahidharia 7 Comments

If you’ve ever spent time online buying electronic doodads — which would mean almost all of us — then sooner or later, the websites get wind of your buying sprees and start offering “suggested” advertisements for buying more useless stuff. One commonly offered popular product seems to be a universal component tester, often referred to as a “Mega328 Transistor Tester Diode Triode Capacitance ESR Meter”. These consist of an ATmega328, an SPI LCD display, a Button, a ZIF socket and a few other components. Almost all of them are cheap clones of the splendid AVR-TransistorTester project by [Markus Frejek]. [Robson Couto] got one of these clone component testers, and after playing with it for a while, decided to hack it and write a T-Rex runner game for it.

The T-Rex runner game is Chrome’s offering for you to while away your time when it can’t connect to the internet. It needs just one button to play. This is just the kind of simple game that can be easily ported to the Component Tester. The nice take away from [Robson]’s blog post is not that he wrote a simple game for an ATmega connected to an LCD display, but the detailed walk through he provides of the process which can be useful to anyone else wanting to dip their feet in the world of writing games.

After a bit of online sleuthing and some multimeter testing, he was able to figure out that the LCD controller chip was connected to Port D of the ATmega, which meant the use of software SPI via bit-banging. He then looked inside the disassembled firmware to find writes to Port D to figure out pin assignments. Of course not long after all this work he found a config.h file with the pin mappings.

Armed with this information he was able to use the Adafruit ST7565 library to drive the LCD, but not before having to flip the image. The modified fork of his ST7565 library is available on GitHub. His game code is also available, but reading through the development process is pretty interesting. Check out a video of the Runner game in action after the break.

In an earlier post, we did a product review of one of these cheap Transistor Testers, and if you have one of these lying around, give [Robson]’s game a spin — it could be handy while you wait for your reflow oven to finish its soldering cycle.

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Moving Microns With A High Precision Linear Stage

February 22, 2017 by Jenny List 32 Comments

As anyone who has experimented with their own home-made CNC machinery will tell you, precision isn’t cheap. You can assemble a gantry mill using off-the-shelf threading and kitchen drawer slides. But it’s a safe assumption that if you put the tool at a particular position it won’t be quite at the same position next time you return. But if you take your budget from dirt cheap to reasonably priced you can do much better. [Adam Bender] designs high-precision automation systems for a living, so when he needed a precision linear stage for a personal project he achieved micron level accuracy for under $500.

micron-precision-linear-actuator — Red parts are the two spring-loaded nuts

He explains the problem of backlash with an inexpensive lead screw — the wiggle between threaded components that cause positional chaos. His solution uses two nuts preloaded against each other with a spring. There is still a stick-slip issue; a tendency to move in lurches due to differences between the coefficients of static and dynamic friction between the materials. Careful choice of machining stock for the nut to picking materials in which these coefficients were almost identical reduced the stick-slip to as little as possible.

He goes into significant detail on the design, manufacture, and testing of all the components of his stage, its body, sealing system, and control. If you are a precision CNC guru maybe you’ll find it interesting as a cleverly designed component, but if you are a mere dilettante you’ll find it fascinating to read a comprehensive but accessible write-up from a professional in the field.

This build probably goes a step beyond most we’ve featured in the past, but that’s not to say we’ve not seen some pretty good efforts.

Zork Comes To Custom FPGA CPU (Again)

February 21, 2017 by Al Williams 9 Comments

[Robert Baruch] wanted to tackle a CPU project using an FPGA. One problem you always have is you can either mimic something that has tools and applications or you can go your own way and just build everything from scratch (which is much harder).

[Robert] took the mimic approach–sort of. He built a CPU with the express idea of running Infocom’s Z-machine virtual machine, which allows it to play Zork. So at least when you are done, you don’t have to explain to your non-tech friends that it only blinks an LED. Check out the video, below, for more details.

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Decimal Oscilloclock Harks Back To 1927 Movie

February 21, 2017 by Anool Mahidharia 25 Comments

Metropolis is a classic, silent film produced in 1927 and was one of the very first full length feature films of the science fiction genre, and very influential. (C-3PO was inspired by Maria, the “Machine human” in Metropolis.) Within the first couple of minutes in the film, we get to see two clocks — one with a 24-hour dial and another larger one with a 10-hour dial. The human overlords of Metropolis lived a utopian 24 hour day, while the worker scum who were forced to live and work underground, were subjected to work in two ten-hour shifts during the same period.

[Aaron]’s client was setting up a Metropolis themed man-cave and commissioned him to build a Metropolis Oscilloclock which would not only show the 24 hour and 10 hour clocks from the film, but also accurately reproduce the clock movements and its fonts. [Aaron]’s Oscilloclock is his latest project in the series of bespoke CRT clocks which he has been building since he was a teen.

The clock is built around a Toshiba ST-1248D vintage oscilloscope that has been beautifully restored. There are some modern additions – such as LED glow indicators for the various valves and an external X-Y input to allow rendering Lissajous figures on the CRT. He’s also added some animations derived from the original poster of the film. Doing a project of this magnitude is not trivial and its taken him almost eight months to bring it from concept to reality. We recommend looking through some of his other blog posts too, where he describes how oscilloclocks work, how he builds the HV power supplies needed to drive the CRT’s, and how he ensures vibration and noise damping for the cooling fans used for the HV power supplies. It’s this attention to detail which results in such well-built clocks. Check out some of [Aaron]’s other awesome Oscilloclock builds that we have featured over the years.

The film itself has undergone several restoration attempts, with most of it being recovered from prints which were discovered in old archives. If you wish to go down that rabbit hole, check out Wikipedia for more details and then head over to YouTube where several versions appear to be hosted.

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Reverse Engineering Enables Slick Bluetooth Solution For Old Car Stereo

February 21, 2017 by Dan Maloney 21 Comments

Those of us who prefer to drive older cars often have to make sacrifices in the entertainment system department to realize the benefits of not having a car payment. The latest cars have all the bells and whistles, while the cars of us tightwads predate the iPod revolution and many lack even an auxiliary input jack. Tightwads who are also hackers often remedy this with conversion projects, like this very slick Bluetooth conversion on a Jeep radio.

There are plenty of ways to go about piping your favorite tunes from a phone to an old car stereo, but few are as nicely integrated as [Parker Dillmann]’s project. An aftermarket radio of newer vintage than the OEM stereo in his 1999 Jeep would be one way to go, but there’s no sport in that, and besides, fancy stereos are easy pickings from soft-top vehicles. [Parker] was so determined to hack the original stereo that he bought a duplicate unit off eBay so he could reverse engineer it on the bench. What’s really impressive is the way [Parker] integrates the Bluetooth without any change to OEM functionality, which required a custom PCB to host an audio level shifter and input switch. He documents his efforts very thoroughly in the video after the break, but fair warning of a Rickroll near the end.

So many of these hacks highjack the tape deck or CD input, but thanks to his sleuthing and building skills, [Parker] has added functionality without sacrificing anything.

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