Teaching the Speak & Spell four (and more) letter words

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Before it became the darling of circuit benders the world over, the Speak & Spell was a marvel of modern technology. Complete with a microprocessor and voice synthesizer, the Speak & Spell was able to speak a limited vocabulary that [Furrtek] thought should include words such as, “al qaeda”, “necrosis”, and “butt”. The Speak & Spell included an expansion port for cartridges containing a larger vocabulary, and with a huge amount of effort [Furrtek] created his own Speak & Spell carts that allow it to talk like a sailor.

The Speak & Spell ROMs were stored on a very strange memory chip; instead of a parallel or serial interface, the chip reads five nybbles at a time before returning the saved data. At first, [Furrtek] thought he could get an ATtiny microcontroller, but the way this memory chip is set up made it impossible to send and receive data even on a 400kHz I2C bus.

The project eventually found some decent hardware in the form of a CPLD-based cartridge that was more than fast enough to interface with the Speak & Spell. After that, it was only an issue of converting words into something the speech synth can understand with some old Windows 3.1 software and finally burning a ROM.

The end result is a Speak & Spell with a perverse vocabulary and is much, much more interesting than a circuit bent piece of hardware with a few wires crossed. Check out the video after the break.

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Turning four smaller helicopters into one larger quadcopter

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There’s a reason we’ve seen a menagerie of quadcopters over the past few years – the key piece of any quadcopter build is an inertial measurement unit. Historically a very complicated and expensive piece of kit, these IMUs came down in price a few years back, allowing anyone with a few dollars in their pocket and a handful of brushless motors to build a four-bladed drone in their workshop.

[Starlino] built a few quadcopters, but he wanted to shy away from IMUs and get most of the mass of his new ‘copter over the center of the chassis. He came up with a design he calls the quadhybrid that can be built out of a quartet of those cheap 3-channel helicopter toys.

Most of the lift for [Starlino]‘s quadhybrid comes from a pair of coaxial rotors from a Syma 001 3-channel helicopter toy. Anyone who has played with one of these toy helicopters knows how stable they are; if the tail rotor breaks, you’re left with a helicopter that can only go up and down.

To give his quadhybrid a few degrees of freedom, he attached four tail rotors from 3-channel helis to a few booms laid out in a cross pattern. By taking the receiver out of a 4-channel helicopter and adding his own controller board, [Starlino] made each of the tail rotors control the pitch and roll of the craft.

In the video after the break, you can see the quadhybrid is amazingly stable even without an IMU and surprisingly agile. As [Starlino]‘s ‘copter can be made out of replacement parts for cheap 3-channel helis, we’ll expect a rush on these tail motors at your favorite online RC retailer very shortly.

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