Little Laser Light Show is Cleverly Packaged, Cheap to Build

We’re suckers for any project that’s nicely packaged, but an added bonus is when most of the components can be sourced cheaply and locally. Such is the case for this little laser light show, housed in electrical boxes from the local home center and built with stuff you probably have in your junk bin.

When we first came across [replayreb]’s write-up and saw that he used hard drives in its construction, we assumed he used head galvanometers to drive the mirrors. As it turns out, he used that approach in an earlier project, but this time around, the hard drive only donated its platters for use as low mass, first surface mirrors. And rather than driving the mirrors with galvos, he chose plain old brushed DC motors. These have the significant advantage of being cheap and a perfect fit for 3/4″ EMT set-screw connectors, designed to connect thin-wall conduit, also known as electromechanical tubing, to electrical boxes and panels. The motors are mounted to the back and side of the box so their axes are 90° from each other, and the mirrors are constrained by small cable ties and set at 45°. The motors are driven directly by the left and right channels of a small audio amp, wiggling enough to create a decent light show from the laser module.

We especially like the fact that these boxes are cheap enough that you can build three with different color lasers. In that case, an obvious next step would be bandpass filters to split the signal into bass, midrange, and treble for that retro-modern light organ effect. Or maybe figuring out what audio signals you’d need to make this box into a laser sky display would be a good idea too.

Continue reading “Little Laser Light Show is Cleverly Packaged, Cheap to Build”

Hackaday Prize Entry: Real Hard Drives In The Raspberry Pi

‘Boy, I wish the Raspberry Pi had a SATA port’. This is the plea that echoes through the Internet, and for once, the Internet is not wrong. A SATA port — or any connector to a big, dumb spinny disk — would be a great addition to the Raspberry Pi ecosystem.

[AlanH]’s entry to the Hackaday Prize is the exact opposite of what everyone wants. The NetPi-IDE is a Parallel ATA IDE disk emulator that turns an inexpensive Raspi Zero into a big, dumb, unspinny hard drive. Drop this machine in your Windows 98 Starcraft battlestation, and you have a hard drive that you can ssh into.

As with any build involving a lot of data, bandwidth is important. The highest bandwidth interface on the Pi’s GPIO ports is the SPI interface. [AlanH] is hanging a Lattice MachXO2 FPGA off the SPI port and using that to emulate a disk. In the future, he’s going to move to the much more open Lattice iCE40HX, compatable with the Open Source IceStorm synthesis chain.

The feature set for this project includes proper IDE disk emulation with sizes ranging from 10 Megabytes to 8 Gigabytes tested so far. If you need anything bigger, you don’t need an IDE drive. A DOS redirector allows mounting any arbitrary directory to a DOS drive letter, a virtual network interface turns this project into The Cloud™, and a serial console is mapped to unused IDE registers, allowing any host system to login to the Pi without any external cables.

While it’s not what everyone wants in a Pi, this is an exceptionally cool project. PATA drives are getting old, and the systems supporting them are too. If you want to keep those retrocomputers running, we have to start planning now, and there’s no better way to do that than with cheap hardware and Open Source toolchains.

Do you trust your hard drive indication light?

Researchers in the past have exfiltrated information through air gaps by blinking all sorts of lights from LEDs in keyboards to the main display itself. However, all of these methods all have one problem in common: they are extremely noticeable. If you worked in a high-security lab and your computer screen started to blink at a rapid pace, you might be a little concerned. But fret not, a group of researchers has found a new light to blink (PDF warning). Conveniently, this light blinks “randomly” even without the help of a virus: it’s the hard drive activity indication light.

All jokes aside, this is a massive improvement over previous methods in more ways than one. Since the hard drive light can be activated without kernel access, this exploit can be enacted without root access. Moreover, the group’s experiments show that “sensitive data can be successfully leaked from air-gapped computers via the HDD LED at a maximum bit rate of 4000 bit/s (bits per second), depending on the type of receiver and its distance from the transmitter.” Notably, this speed is “10 times faster than the existing optical covert channels for air-gapped computers.”

We weren’t born last night, and this is not the first time we’ve seen information transmission over air gaps. From cooling fans to practical uses, we’ve seen air gaps overcome. However, there are also plenty of “air gaps” that contain more copper than air, and require correspondingly less effort.

Continue reading “Do you trust your hard drive indication light?”

Brushless HDD Motor Driver from 9V and Painter’s Tape

Hard drives work by spinning platters full of magnetized data while a read/write head very quickly harvests or changes bits as needed. Older (or perhaps cheaper) drives spin at 5400 RPM, better drives spin at 7200 RPM, and elite drives (that mortals like you never shell out for) spin in the 10k-15k RPM range. This spinning is thanks to a sweet combination of a bearing and a brushless DC motor.

Unfortunately you can’t drive a brushless motor without a brushless motor driver. Well, of course that’s not absolutely true — and [Tommy Callaway] has certainly hacked together a crude exception to the rule. He’s using a 9-volt battery and some blue painters tape to drive a brushless motor.

Brushless motors do their thing by placing permanent magnets on the rotor (the part that spins) and placing multiple stationary coils of wire around it. Brushless motor drivers then energize these coils in a vary carefully timed pattern to continuously push the rotor magnets in the same direction.

[Tommy] wired up his 9V to one of these coils and observed that it holds the rotor in position. He then began playing around with different ways automatically break the circuit to de-energize the coil at just the right time. This means using the spinning center of the hard drive as part of the circuit, with blue painter’s tape in alternating patterns to create the timing. Is this a brushless motor driver, or has he just re-invented the brushed motor?

If this workbench trick leaves you wanting for some hardcore BLCD action, you can’t go wrong with this $20 offering to push motors at very high speeds.

Continue reading “Brushless HDD Motor Driver from 9V and Painter’s Tape”

Real World Race Track is Real Hack

[Rulof] never ceases to impress us with what he comes up with and how he hacks it together. Seriously, how did he even know that the obscure umbrella part he used in this project existed, let alone thought of it when the time came to make a magnet mount? His hack this time is a real world, tabletop race track made for his little brother, and by his account, his brother is going crazy for it.

His race track is on a rotating table and consists of the following collection of parts: a motor, bicycle wheel, casters from a travel bag, rubber bands (where did he get such large ones?), toy car and steering wheel from his brother, skateboard wheels, the aforementioned umbrella part and hard drive magnets. In the video below we like how he paints the track surface by holding his paint brush fixed in place and letting the track rotate under it.

From the video you can see the race track has got [Rulof] hooked. Hopefully he lets his brother have ample turns too, but we’re not too sure. Some additions we can imagine would be robotics for the obstacles, lighting, sounds and a few simulated explosion effects (puffs of flour?).

Continue reading “Real World Race Track is Real Hack”

Another Use for Old Hard Drive Parts: Anemometer

So you’ve just taken apart a hard drive, and you’re looking at all the pieces on your desktop. You’re somehow compelled to use them all in different projects. Why not pull out that very high quality bearing that keeps the platters spinning at high RPMs and build this simple anemometer with it? That’s what [Sergei Bezrukov] did, and it looks like a perfect el cheapo project.

The build is fairly low-tech and entirely sufficient. The cups are made from plastic containers that used to contain pantyhose. A Hall-effect sensor and a magnet take care of measuring the rotations, feeding its signal into a PIC that calculates the wind speed from the revolution rate. The rest of the housing is PVC, with some other miscellaneous parts found at the hardware store.

To calibrate the device, [Sergei] made a second hand-held unit that he could (presumably) drive around in a car to get a baseline wind speed, and then note down the revolution rate. Once you’ve got a good reference, holding the portable unit up to the permanent one transfers the calibration.

But the star of the show, that lets the anemometer spin effortlessly, is the sweet bearing that used to spin a hard-drive platter. If you haven’t played with one of these bearings before, you absolutely should. We just ran a post on taking apart a hard drive for its spare-parts goodness so you have no excuse. If you’re feeling goofy, you can mount one onto a board, step on it with the ball of your foot, and spin. They’re quality bearings, and you’ll be surprised how quickly you can spin as you pull your arms in.

Thank [Matt] for the tip!

Hard Drive Disassembly is Easy and Rewarding

Have any dead hard drives kicking around? Hackaday alum [Jeremy Cook] shows how easy it is to disassemble a hard drive to scavenge its goodies. The hardest part is having the patience and the tools to get past all those screws that stand between you and the treasure inside.

The case screws are frequently of the Torx variety. Any self-respecting hacker probably has one or two of these already, but if you’re in the market, [Jeremy] recommends a nice set that looks way better than ours. Once the case is open, you can find rare earth magnets, bearings, and one or more platters.

Those terrifically strong magnets are good for all kinds of projects. Glue a couple of them to the back of an attractive piece of wood, mount it on the kitchen wall, and you have yourself a knife block. Keep a couple on the bench to temporarily magnetize tools. Use them to build a pickup to amplify a cigar box guitar or thumb piano. Or run the pickup into a small amplified speaker and wave it like a stethoscope near your electronics to hear them hum. As far as liberating the magnets goes, [Jeremy] resorted to clamping his in a vise and using a hammer and chisel to pry it away from the actuator hardware.

You’ve no doubt seen clocks made from old hard drives that were kept mostly intact. Many makers including [Jeremy] will extract the shiny platters to use as bases for clock faces and engrave the numbers, etch them, or glue them on. Those platters also make excellent chimes. Even if you just hang one platter off of a finger and tap it with a fingernail, it sounds really nice.

If simple chimes don’t really butter your muffin, there are all kinds of sonic projects for dead hard drives. How about making a microphone or speakers? Maybe an HDD MIDI controller or a synthesizer is more your speed. Speaking of synths, watch [Jeremy] take a hard drive apart to some sweet sounds after the break.

Continue reading “Hard Drive Disassembly is Easy and Rewarding”