Separating a working scanner from its broken printer

The laser printer portion of this all-in-one machine gave up the ghost and [Entropia] couldn’t get it working again. But the scanner was still functioning so he decided to separate the scanner from its dead printer module.

The model in question is a Samsung SCX-4200. The design is actually perfect for separation because the scanner sits on top of the out feed tray of the printer. It can even be lifted to allow more room for printed pages to pile up. All he has to do is separate the hinged connector and reroute the flat cables. But the real question in [Entropia’s] mind was whether or not the control board would work without the laser printer components connected to it.

He carefully disassembled the unit, spilling toner here and there which is left over from a catastrophic knock-off toner cartridge incident. A quick test showed him that although the drivers complain that the paper tray is open, the scanner does still work. He glued the controller board seen on the left to the bottom of the scanner enclosure, and added some felt feet. Now his scanner is closer to the size you’d expect. And on the plus side he gained a geared stepper motor, laser scanning unit, exhaust fan, and a couple of solenoids to use in future projects.

Trumpet Hero

[Evilsigntist] combined an old cornet with an old PS2 guitar hero controller to produce the Trumpet Hero. The fragile looking conglomeration really brings a smile to our faces. Just make sure the instrument has already seen the end of its days before drilling holes to mount the various parts.

In the image above you can see that the three valve buttons have been painted to correspond to frets on the original guitar controller. The orange and blue frets are positioned for the left hand to operate. There seems to be a couple of different version because there is a diagram showing a mute in the bell that can be twisted for whammy bar input, but that’s not shown here. Strumming is accomplished by blowing through the mouthpiece, but as you can see in the video after the break, no buzzing is necessary.

Using actual instruments as game inputs is a lot of fun. We always think back to the flute and drum set controllers for Rock Band.

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Doppler-effect lets you add gestures to your computer

What if you could add gesture recognition to your computer without making any hardware changes? This research project seeks to use computer microphone and speakers to recognize hand gestures. Audio is played over the speakers, with the input from the microphone processed to detect Doppler shift. In this way it can detect your hand movements (or movement of any object that reflects sound).

The sound output is in a range of 22-80 kHz which is not audible to our ears. It does make us wonder if widespread use of this will drive the pet population crazy, or reroute migration paths of wildlife, but that’s research for another day. The system can even be used while audible sounds are also being played, so you don’t lose the ability to listen to music or watch video.

The screen above shows the raw output of the application. But in the video after the break you can see some possible uses. It works for scrolling pages, double-clicking (or double-tapping as it were), and there’s a function that detects the user walking away from the computer and locks the screen automatically.

[Sidhant Gupta] is the researcher who put the video together. In addition to this project (called SoundWave) he’s got several other interesting alternative-input projects on his research page. [Read more…]

Software defined radio from a USB TV capture card

With a simple digital TV USB capture card, you can build your own software defined radio or spectrum analyzer. While it may not be as cool as [Jeri Ellsworth]’s SDR, it’s still very useful and only requires $20 in hardware.

The only piece of hardware required for this build is a USB FM/DTV capture device with the Realtek RTL2832U chipset. So far, two USB sticks have been tested and the unit with the largest frequency range (64 – 1700 MHz) is available direct from China for $20.

Turning these cheap capture cards into software defined radios and spectrum analyzers was discovered by [Antti Palosaari] after sniffing the device. These cards demodulate the frequency and send all the data to the computer and is decoded via software. If you have one of these capture cards lying around, you can grab the software and load it up on your *nix box. Right now, the software only writes directly to a file, and may drop a few samples if writing to a hard disk instead of ram. Small problems, but we’re sure this project will pick up steam in the very near future.

via reddit

Isomorphic piano keyboard is button madness

[nikescar] sent in a link to a huge isomorphic MIDI keyboard. We might have missed it the first time around, but that doesn’t diminish such a great looking project.

According to the project page, this humongous keyboard is the work people at Louisville Soundbuilders’ efforts to clone the AXiS-64 MIDI controller. Instead of looking like a ‘normal’ piano keyboard, this isomorphic keyboard puts notes in a hexagonal pattern. This keyboard layout is very useful – fingerings for chords are the same across all keys – but these keyboard layouts are fairly rare and MIDI controllers are expensive as a result.

To make the keyboard in the video velocity sensitive, there are two layers of PCBs. The top layer uses Cherry key switches, while the bottom PCB is an array of tact switches. Measuring the time between the top and bottom key presses gives the on board microcontroller velocity information that is converted to MIDI notes. This setup has a few downsides, namely the huge amount of switches, components, and pins needed for two keyboard matrices.

The project page hasn’t been updated for a few months, so we’re pretty curious about the current status of this build. If any of the Louisville Soundbuilders have an update on this project, send it on in.

Using the nook as a keyboard

[Andrew] has been pining for an Optimus Maximus – a keyboard with a small LCD screen in each key – for years. Like a lot of people, he love the idea of a completely configurable keyboard, but balked at the two thousand dollar price tag. Although it doesn’t have full color OLED screens behind each key, [Andrew]’s nook simple touch can be used as a keyboard just the same.

After rooting his new nook, [Andrew] had a very nice tablet computer, and the only Android device with an e-ink screen. Although[Andrew] never wrote an Android app before, he wanted to do a proof of concept build to see if a nook keyboard would actually work. The “keyboard app” is actually just a webpage hosted on his home server. When he presses a virtual key, JavaScript sends an ASCII value back to the server where it is decoded and sent to xte.

[Andrew] says his build works, but not very well. Opera mini doesn’t like the homebrew server he set up, and Cyrillic characters are a no go. Still, it works, and looks like an awesome application for an e-ink tablet with a proper Android app. Demo after the break.

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