Video Preview: New IOIO prototype

We got our hands on this prototype of the new IOIO design. It’s a breakout board that makes adding hardware to an Android device pretty easy.  [Ytai Ben-Tsvi] sent it our way, and took a bit of time to explain some of the differences between this board and the original version. You can see our video preview embedded after the break.

The size and form factor of the board remain the same, but the choice and layout of parts has changed. Most obviously, the USB-A connector is gone, replaced by a USB mini-B micro-B connector. This makes it possible to use the board as a USB-on-the-go device, or as a USB host device with the help of an adapter that will ship with the board. The JST connector is for external power. The previous revision included a footprint for it but it was never populated. There has also been an upgrade to the voltage regulation circuit, using a newer part as the switch-mode regulator.

There was a last-minute bug discovered in the layout. [Ytai] wants iron-clad 5V to ground short protection and is re-spinning the board to ensure he achieves that goal. He can’t say for sure, but as we mentioned in our previous post about the prototype, a price cut is planned. It could cut the current price of $50 down to just $30, but that won’t be decided until all of the choices have been made for the first production run.

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How to make your own piezoelectric speaker

Piezoelectric speakers are found all around you, from musical greeting cards to the tweeters in your car stereo setup. Making your own piezo speakers is actually very easy, as [Steven] shows us after replacing the speaker in a clock radio.

Piezo speakers require a small crystal with piezoelectric properties, so this build is the perfect followup to [Steven]‘s tutorial for making Rochelle salt crystals. After attaching two strips of aluminum foil to his Rochelle salt crystal, [Steven] took the wires that previously went to the clock radio speaker, connected them to the crystal, and turned on the radio. When attached to a tin can, the newly created piezo speaker created a little bit of sound, but the results weren’t very impressive.

To boost the sound output of his homemade speaker, [Steven] needed to increase the voltage across his piezo speaker. At first he tried a doorbell transformer with somewhat better results, but much more sound was produced when he used a transformer taken from a microwave oven.

After experimenting with his microwave transformer and Rochelle salt, [Steven] moved on to piezo elements found in BBQ and cigarette lighters. These homemade speakers were much clearer than the chunk of Rochelle salt he was using previously, and surprisingly produced about the same audio quality as a commercially made piezo speaker [Steven] picked up at Radio Shack.

You can check out the build video for [Steven]‘s crystal speaker after the break.

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Ask Hackaday: Who likes retrocomputing?

Last week we posted a link to Project Kiwi, a homebrew Motorola 68008-based microcomputer built by [Simon] that includes Ethernet, a very good display adapter, an interface for IDE hard disks, two Commodore SID chips (for stereo chiptunes), a floppy disk controller, and an already existent software library that will make it very easy to develop your own software for this wonderful computer.

After thinking about [Simon]‘s Project Kiwi for a while, I’ve been thinking there really hasn’t been a homebrew computer made that is so perfect for a proper Open Hardware release. There are more than enough peripherals in the computer to make development very fun. I’ve suggested doing a group buy to get Kiwi PCBs out into the wild and into the hands of other retrocomputer fanatics, but [Simon] would like a little more feedback.

Of course, this means turning to you, the wonderful Hackaday reader. Would any of you be interested in your own Kiwi microcomputer?

[Simon] tells me there are a lot of problems for turning the Kiwi microcomputer into a Open Hardware project. His prototype PCB cost €300, greatly reducing the number of people who would be interested in making their own Kiwi. Also, there are a few problems on the current PCB design (easily fixed for the next revision), and [Simon] would like to add a few features like DMA and a proper framebuffer.

Despite all those problems, I can’t see a better way to learn about computer architecture the hard way (i.e. 80′s microcomputers as opposed to futzing around with a Raspberry Pi). You’ll also get a really wonderful computer system that will show the power of 80s-era electronics, with the very hopeful goal of spreading the gospel of retrocomputing with the venerable Saint MC68000.

If you’d like to add your two cents – if having an Open Hardware 80s microcomputer is a good idea, or some technical requests such as adding a proper 68000 CPU to future designs, leave a note in the comments or on the forum [Simon] set up on his Kiwi page.

I think it’s a cool idea, but then again I’m probably blinded by how cool an 80s computer of this caliber is. The fate of this project is now in your hands.

Robotic odometry from an optical mouse

One of the problems future engineers spend a lot of class time solving is the issue of odometry for robots. It’s actually kind of hard to tell how far a robot has traveled after applying power to its wheels, but [John] has a pretty nifty solution to this problem. He converted an optical mouse into an odometry sensor, making for a very easy way to tell how far a robot has traveled  regardless of wheels slipping or motors stalling.

The build began with a very old PS/2 optical mouse he had lying around. Inside this mouse was a MCS-12085 optical sensor connected to a small, useless microcontroller via a serial interface.

After dremeling the PCB and discarding the microcontroller, [John] was left with an optical sensor that recorded distance at a resolution of 1000dpi. It does this by passing a value from -128 to 127, rolling over every time the sensor moves more than 3.2 mm.

As far as detecting how far a robot has moved, [John] now has the basis for a very simple way to measure odometry without having to deal with wheels slipping or motors stalling. We can’t wait to see this operate inside a proper robot.

Hackaday Links: Sept 15, 2012

Very tiny keyboard

The idea behind the iControlPad2 is pretty simple – just take the slide-out keyboard from a phone, discard the phone part, add two analog sticks and a D-pad, and put Bluetooth in it. It makes for a very small keyboard perfect for controlling a Raspi, a home media server, or even a phone or tablet. I think it’s cool, anyway.

I mustache you a question. Where’s the Hawaiian Shirt?

At her local hackerspace, [Akki] heard someone pronouncing Raspberry Pi as, “Raspberry pee eye.” Of course this joke needed to be taken to its fullest absurdity, so [Akki] gave her Raspi a [Tom Selleck] mustache. Slightly better than the Googly Eyes Arduino shield.

Not giving a Flip about proprietary batteries

When powering a Flip video camera, [Dan] had two choices: regular AA batteries, or a proprietary battery rechargeable through the USB port. When the rechargeable battery is inserted, it closes a small switch telling the Flip it can recharge these batteries. Wanting to put his own rechargeable batteries in his camera, [Dan] closed the switch with a little bit of cardboard, thus allowing him to use his own NiMH rechargeable batteries.

Building operating systems from scratch

A while ago we posting something about a Cambridge professor putting up a tutorial for developing an operating system from scratch on the Raspberry Pi. [Joey] decided to follow these tutorials and has a blog dedicated to his adventures in OS development. It’s not a custom UNIX-inspired OS yet….

Put a quarter in, get a goldfish

[Yooder] over on Reddit spent a week turning a gumball machine into a fish tank. A very nice build that is now home to a few neon tetras. Check out the imgur album for a full build walkthrough.