Watermelon air boat


We think you’ll turn a few heads in Central Park if you’re driving a water melon around when everyone else is piloting sailboats. This watermelon is both sea worthy and radio controlled thanks to the work which [Starting Electronics] put into it.

We used this image because it shows you what’s inside of the hull, but you don’t want to miss the thing motoring around an above-ground swimming pool in the clip after the break. The hollowed out shell is quite buoyant and has no problem staying afloat and upright with the addition of a propeller. The parts from a remote control airplane kit have been mounted on a wooden scaffold. This provides plenty of thrust with a servo motor moving turning the prop for directional control. There is no dagger board so the craft is a bit slow to respond to turns. But how responsive do you expect a floating melon to be?

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Creating a MIDI synth from a Commodore SID

The Commodore SID was the audio chip in the venerable Commodore 64 and in the 30 years since release has attained classic status and become one of the best ways to get your chiptune on. Designed by famous synthesizer designer [Bob Yannes], it was only a matter of time before we saw a real, homebrew MIDI synth based on the Commodore SID.

Because real SID chips are rare as hen’s teeth nowadays, [Jeff Ledger] built his SID synth around an emulated system running on a Pocket Mini Computer. This very cool microcontroller platform runs on the Parallax Propeller. An emulated SID runs in one of the Propeller’s 8 cores, with the remaining cores kept open for reading MIDI notes and displaying info on a display.

The hardware portion of this build is amazingly simple; just an optoisolater, a few resistors, and a diode connect a MIDI keyboard to the Pocket Mini Computer. The buttons and dials on [Jeff]‘s MIDI keyboard control the waveforms, filters, and envelope controls. A very neat setup if we do say so ourselves, and just perfect if you’re needing more chiptunes in your life.

You can check out [Jeff]‘s video after the break.

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Programming a Propeller on an ARM

[Stefan] uses a small ARM-powered netbook for his development work, so when he tried to play around with the Parallax Propeller he ran into a few problems. The official tools from Parallax are Windows only, and the available 3rd party dev tools are only compiled for x86. After a lot of futzing about, [Stefan] was able to develop on his ARM netbook and wrote in to tell us how it’s done.

Luckily, Parallax released a GCC port for the Propeller, but unfortunately isn’t completely portable to ARM. The Propeller loader for this architecture ambivalent build uses a little bit of SPIN code, which can only be compiled on Intel machines.

To get around this problem, [Stefan] wrote an installer script to gather all the necessary bits of code to his computer. His ARM/Linux toolchain consists of the Propeller GCC, an open source SPIN compiler, and a Python script used to load code [Stefan] found on the Propeller forums.

Now that [Stefan] has a complete toolchain for programming the Propeller on an ARM device, it’s possible to develop for this very cool multi-core microcontroller on his netbook or even the Raspberry Pi.

ProtoSynth, the prototyping synthesizer

This project isn’t really a prototype, but a tool for prototyping. [Tymkrs] came up with a unique way to build this synthesizer prototyping tool. They actually patched into the underside of the breadboards in order to keep all of the permanent bits nice and tidy.

In the clip after the break you’ll see all of the build photos that lead up to this point. After cutting out and assembling the wooden pieces for the case they grab a soldering iron and get to work. Two octaves worth of keys were pulled out of an electric keyboard. Ribbon cable is soldered onto each key’s electrical connection, with an SIL pin header as a connector. This mates with another ribbon cable with a SIL socket on one end, and an IDC connector on the other. The real trick is getting that IDC connected to the breadboard. They cut back the adhesive tape on the underside of the board and soldered a surface mount pin header onto it. This way the inputs from the keys, as well as a few 1/4″ jacks from the back of the case are always available in a tidy way on the breadboards. The video goes on to show preliminary synthesizer work on the device.

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Reliving the BBS days with a Propeller

Back before the world wide web, self-proclaimed geeks would get our compute on by dialing in to bulletin board systems. In their heyday, these BBSes were filled with interesting people and warez to fill the most capacious 10 Megabyte hard drive. In an attempt to relive the days of the Internet before the Eternal September, [Jeff Ledger] whipped up a tutorial for dialing up BBSes with an updated classic computer.

Instead of doing this tutorial with a C64 or an Apple II, [Jeff] used the Propeller powered Pocket Mini Computer he designed. This computer features 32Kb of RAM inside an eight-core Parallax Propeller along with a BASIC interpreter to run your own programs.

This Mini Computer can connect to BBS systems, but seeing as how acoustically coupled modems are rare as hen’s teeth these days, [Jeff] thought it would be a good idea to log in to the many Internet connected BBS servers using his desktop as a bridge between the Propeller and the Internet.

After [Jeff] got his Propeller computer up and running on a BBS, he was free to play Trade Wars or slay grues in one of the many MUDs still running. Not bad for a demonstration of the Internet of old, and made even better by the use of a Propeller.

Control everything in your car with the Car Kracker

If your whip is a Honda, Toyota, BMW, Chrysler, VW, or Mini made in the last decade or so, the Car Kracker is for you. This project allows you to connect directly to your car’s computer system, allowing you to display messages on your stereo, play music off an SD card, and even override factory settings like always-on daytime running lights.

The Car Kracker uses ISO 9141, an in-car communications protocol that is now mostly used in foreign (for the US) cars. The build uses a Gadget Gangster Propeller board to connect to the CD changer port and OBD-2 port in the trunk, and the diagnostic port located under the hood.

With the Car Kracker, it’s easy to connect the Aux In on your stereo to an SD card loaded with music, or even plug in an iPod for the poor souls without a 1/8″ jack. Dealer customizations such as turning the ‘door is ajar’ noise off, toggling daytime running lights, and throwing a nav warning up are also possible.

Check out the two videos after the break, and if anyone has any more info on getting this deep into a car’s computer system (a wiki, maybe?), send a link in on the tip line.

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Remote control with an XBee and a Propeller

If you’ve been playing with electronics for long enough, eventually you’ll need a nice remote control transmitter to control your RC car, airplane, or any other robotics project you have lying around. With these robotics projects comes the problem remote control, and the XBee Handheld Controller may be just the ticket to remotely control any project that comes off your workbench.

This isn’t the first remote controller we’ve seen that does just about everything, but it is the first one to include an XBee wireless transceiver to easily interface to your robotics project. The controller comes in two models, the Q4, which uses four Playstation-like joysticks, and the Q2, which uses proper remote control gimbal joysticks. Both the controllers have a slew of buttons, toggle switches, four rotary pots and a 2×20 LCD display.

After the break you can check out [Paul]‘s pitch explaining what these controllers can do and showing off a hexapod robot under the control of his Q4 controller. A very neat project, and we can’t wait to see this controller out in the field.

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