Make a Microphone Out of a Hard Drive

[Rulof Maker] has a penchant for making nifty projects out of old electronics. The one that has caught our eye is  a microphone made from parts of an old hard drive. The drive’s arm and magnet were set aside while  the aluminum base was diagonally cut into two pieces.  One piece was later used to reassemble the hard drive’s magnet and arm onto a wooden platform.

v2_micThe drive’s arm and voice coil actuator are the key parts of this project. It was modified with a metal extension so that a paper cone cut from an audio speaker could be attached, an idea used in microphone projects we’ve previously featured. Copper wire scavenged from the speaker was then soldered to voice coil on the arm as well as an audio jack. In the first version of the Hard Drive Microphone, the arm is held upright with a pair of springs and vibrates when the cone catches sound.

While the microphone worked, [Rulof] saw room for improvement. In the second version, he replaced the mechanical springs with magnets to keep the arm aloft. One pair was glued to the sides of the base, while another pair recovered from an old optical drive was affixed to the arm. He fabricated a larger paper cone and added a pop filter made out of pantyhose for good measure. The higher sound quality is definitely noticeable. If you are interested in more of [Rulof’s] projects, check out his YouTube channel.

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Vintage Vinyl Laser-Etched on a Tortilla

[UpgradeTech] had a proof-of-concept itch they needed to scratch: making a playable record out of a tortilla using a laser cutter. The idea was spawned from the goofy “tortilla vinyl” YouTube video.

Uncooked flour tortillas were used. Corn tortillas were too lumpy while cooked tortillas shredded on the record player. To get the recording onto the tortilla, Audacity was used to modify a stereo WAV file. Using the RIAA equalization standard is a great choice here as it was originally adopted to prevent excess wear and tear on record grooves as the needle passed through. A Python script generated the files for the laser cutter, creating a text file with the sound data which was then processed into a vector PDF of the grooves. For each record it takes 30 minutes for the laser cutter to turn a simple flour tortilla into the musical variety.

Each tortilla can play 30-40 seconds of music at 45 or 78 RPM, but they start to warp once they dry out. Time to build a humidor around the record player! There is background noise that can make certain songs harder to hear, but there is unarguably audible music. There is plenty of room for optimizing the sound file, grooves, and cutting. We hope this project inspires others to make their own musical tortilla. Playing with your food has taken on a whole new meaning!

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Codename Colossus: The HMC Boudicca

[Michael Sng], founder of [Machination Studio], wanted to create a toy line unlike anything the world has seen.  He has recently completed the first production prototype in the Codename Colossus toy line: the HMC Boudicca. The egg-shaped HMC Boudicca is tank-like with a definite Metal Slug vibe, but it’s almost a disservice calling it a toy.

The HMC Boudicca is over 20″ tall. It is composed of over 400 parts, a majority of which are 3D-printed or laser-cut. Internal parts are FDM while the external pieces are SLS printed. It is a kinetic piece that walks in a hexapodal fashion, so there are lots of servos, motors, sensors, and LEDs, that are controlled by an Arduino. A lot of work and attention to detail was put into this prototype. The HMC Boudicca was designed to be easily disassembled with a Phillips screwdriver. The electronic components are all plug-in devices, so no soldering is required when it comes time to replace a sensor or servo.

Codename Colossus is a toy line that is made to order and intended to be artisanal in nature. Each piece will be individually hand-painted and assembled like the HMC Boudicca. While no official prices are posted yet on the site, we assume these are not going to be cheap. In fact, the site states that each piece will have a 2% markup from the previously sold price to help maintain the value of the pieces and control cost inflation. This could be a source of contention for potential buyers. It underscores [Michael’s] philosophy that Codename Colossus is meant to be a collectible work of art, an antithesis to mass production.

Regardless of the business strategy, we are interested in seeing any additional designs for this series. It would be fun to see a whole bunch of these marching as one robot army!

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Mini Arc Furnace Melts Its Way Into Our Hearts

[Grant Thompson], aka “The King of Random,” threw caution to the wind when it came to his latest awesome project – a mini electric arc furnace (EAF) (YouTube link). [Grant] uses a refractory brick as a furnace and crucible for the molten metal.  He wears eye protection and a respiratory mask as he cuts up the brick – a good idea, since you don’t want to inhale any of that dust. The electrode grips are made with things you can find at a hardware store, including copper wire and coupling, and 2 pairs of vice-grip style pliers. The copper wire is stripped and attached to the metal handle of the pliers using hose clamps. The pliers are now functional electrode grips- just put a carbon rod in each grip and hold them close to each other…but not without protection! [Grant] harvested the carbon rods  from the cells of 6V lantern batteries – dead batteries work just as well for this. It’s also a better bet to do this outdoors with decent ventilation and away from anything flammable. [Grant] realized that the rods from the batteries have a wax-like coating on them that takes about 30 seconds to burn off in spectacular flames the first time they make electrical contact. However, you can purchase carbon rods by themselves if you want to avoid ripping open batteries and possibly setting yourself on fire. The mini EAF runs on a welding power supply [Grant] made from microwave oven transformers  (YouTube link).

When it’s time to melt some metal, the scrap metal is placed into a bowl drilled into the brick. Using the electrode grips, the carbon rods are placed into the brick’s pre-drilled holes. It only takes ten seconds to melt pure zinc – do NOT do this with galvanized steel or brass castings, as zinc oxide is very hazardous to your health.

In the videos featured below, [Grant] shows a variety of metals are no match for his mini EAF. He even manages to melt rocks from his backyard! It goes without saying that an EAF (video link) can be very dangerous. When you’re dealing with high voltage, plasma, white-hot molten metal, and toxic fumes, you better know what you’re doing (or have a great life insurance policy). [Grant] has a penchant for showcasing projects that can make an OSHA inspector cringe,  but you have to admire his gumption!

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SamplerBox Uses Raspberry Pi 2 to Make Music

[JosephErnest] wanted a cost-effective alternative to the commercially available MIDI samplers and expanders on the market. He also wanted to avoid being tethered to a computer all the time. His solution is the SamplerBox, a standalone drop-and-play sampler that costs less than 100 euros to make. Simply insert an SD card with your sample set in WAV format, boot it up, and play it through your keyboard or MIDI controller to your heart’s content!

[JosephErnest] used a Raspberry Pi 2 in the SamplerBox because it provided higher performance. He wasn’t thrilled with the sound quality of its built-in soundcard, so he installed a USB DAC PCM2704 (an older model, but any USB DAC will do) to output the audio. He also installed a USB card reader to make switching SD cards containing sampler sets easier while keeping the Pi 2’s own microUSB card exclusively for the OS and software. Both a DIN MIDI connector and USB are included as MIDI inputs in the design. If you only plan to use a USB, the MIDI connector can be omitted from the build. The software is written in Python and cython which allows the Pi 2 to have over 128-voice polyphony. Users can also create their own sample sets to use with the SamplerBox. Preset changes can be made on the fly. All we need to rock out are some music lessons!

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“Giger Counter” Makes Radiation Detection Surreal

Here’s a quick question: are Geiger and Giger (as in H.R. Giger, designer of the Alien Xenomorph) pronounced the same? The answer is no. Nevertheless, the late artist has had his name mispronounced (for the record, it’s ghee-gur) by many over the years. [Steve DeGroof’s] friend posted a goofy tweet that gave him the inspiration to finally put a skeletal lid on the matter, the Giger Counter.

The innards are a Mightyohm Geiger Counter Kit. The external casing is where the true hack lies in this project, made from a 1:2 scale plastic skeleton model, flexible conduit, and dark metallic spray paint. Only the ribcage, some vertebrae, and part of the skull are used from the model. They are assembled in a delightfully inhuman fashion with some conduit wrapped around it and into the bottom of the ribcage for good measure. After some gluing and spray painting, the LED from the Geiger Counter kit is placed through a drilled hole in the skull while the board sits inside the ribcage. Getting the board in and out can be a little tricky, but it looks like the batteries can be changed without having to pull the whole board out.

Check out the video below to see the Giger Counter. If you want another hack inspired by H.R. Giger’s artistic vision, take a look at this Xenomorph suit we covered.  Or, if you can’t get enough Geiger counters, we’ve featured plenty of cool ones on this site.

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Pump Up the Volume with the 3D Printed Syringe Pump Rack

Syringe pumps are valuable tools when specific amounts of fluid must be dispensed at certain rates and volumes. They are used in many ways, for administering IV medications to liquid chromatography (LC/HPLC). Unfortunately, a commercial pump can cost a pretty penny. Not particularly thrilled with the hefty price tag, [Aldric Negrier] rolled up his sleeves and made a 3D-printed version for 300 USD.

[Aldric] has been featured on Hackaday before, so we knew his latest project would not disappoint. His 3D Printed Syringe Pump Rack contains five individual pumps that can operate independently of each other. Five pieces are 3D-printed to form the housing for each pump. In addition, each pump is composed of a Teflon-coated lead screw, an Arduino Nano V3, a Pololu Micro stepper motor driver, and a NEMA-17 stepper motor. The 3D Printed Syringe Pump Rack runs on a 12V power supply using a maximum of 2 amps per motor.

While the standard Arduino IDE contains the Stepper library, [Aldric] wanted a library that allowed for more precise control and went with the Accelstepper library. The 3D Printed Syringe Pump Rack has a measured accuracy of 0.5µl in a 10ml syringe, which is nothing to laugh at.

Syringe pump racks like [Aldric’s] are another great example of using open source resources and the spirit of DIY to make typically expensive technologies more affordable to the smaller lab bench. If you are interested in other open source syringe pump designs, you can check out this entry for the 2014 Hackaday Prize.

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