Can You Print With Highlighter Ink?

March 29, 2020 by 30 Comments

With huge swathes of people either out of work or working from home, many are now attempting all manner of exciting or silly projects in their downtime. [Emily Velasco] is no exception. She decided to explore the feasability of printing with highlighter ink.

It’s a messy business. Wear gloves.

The hack starts with a rather ancient inkjet printer, so old that it works with tractor feed paper. [Emily] set about gutting several highlighter pens and squeezed out the ink reservoirs into a ladle. The printer’s ink cartridge was then filled with the fluid, and a test print was fired off. Upon initial extraction, it appears blank. However, with the aid of a UV light, the printed pattern is revealed. It appears that the inkjet is printing a very faint image, such that the system almost works as an “invisible ink”.

It’s a fun little hack with an old printer, made easier as it lacks the DRM of newer models. It’d probably be quite achievable with a dot-matrix, too. If you’re similarly tinkering in the innards of your peripherals, be sure to let us know. Video after the break.

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Got Me Feeling Blue

March 29, 2020 by 22 Comments

Sleep schedules are an early casualty in the fight to be productive. Getting good sleep is an uphill battle, so anything that can help us is a welcome ally. We all know about the phone and computer settings that turn down the infamous blue hues at sunset, but what about when you want more blue light? Maybe you want to convince your body to stay awake to pre-acclimate for a trip across time zones. Perhaps you work or live in a place that doesn’t have windows. Menopause introduces sleep trouble, and that is a perilously steep hill.

[glowascii] takes the approach of keeping-it-simple when they arrange six blue LEDs under a flesh-tone patch, which isn’t fooling anyone and powers the lights with a USB power pack. Fremen jokes aside, light therapy is pricey compared to parts some of you have sitting in a drawer. Heck, we’d wager that a few of you started calculating the necessary resistor sizes before you read this sentence. Even if you don’t need something like this, maybe you can dedicate an afternoon to someone who does.

DIY therapy has a special place in our (currently organic) hearts, such as in this rehabilition glove or a robot arm.
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Bullet-proofing Your Car With An Affordable Composite Armor

January 18, 2020 by 35 Comments

Remember those actions movies like The Fast and the Furious where cars are constantly getting smashed by fast flying bullets? What would it have taken to protect the vehicles from AK-47s? In [PrepTech]’s three-part DIY composite vehicle armor tutorial, he shows how he was able to make his own bulletproof armor from scratch. Even if you think the whole complete-collapse-of-civilization thing is a little far-fetched, you’ve got to admit that’s pretty cool.

The first part deals with actually building the composite. He uses layers of stainless steel, ceramic mosaic tiles, and fiberglass, as well as epoxy resin in order to build the composite. The resin was chosen for its high three-dimensional cross-linked density, while the fiberglass happened to be the most affordable composite fabric. Given the nature of the tiny shards produced from cutting fiberglass, extreme care must be taken so that the shards don’t end up in your clothes or face afterwards. Wearing a respirator and gloves, as well as a protective outer layer, can help.

After laminating the fabric, it hardens to the point where individual strands become stiff. The next layer – the hard ceramic – works to deform and slow down projectiles, causing it to lose around 40% of its kinetic energy upon impact. He pipes silicone between the tiles to increase the flexibility. Rather than using one large tile, which can only stand one impact, [PrepTech] uses a mosaic of tiles, allowing multiple tiles to be hit without affecting the integrity of surrounding tiles. While industrial armor uses boron or silicon carbide, ceramic is significantly lower cost.

The stainless steel is sourced from a scrap junkyard and cut to fit the dimensions of the other tiles before being epoxied to the rest of the composite. The final result is allowed to sit for a week to allow the epoxy to fully harden before being subject to ballistics tests. The plate was penetrated by a survived shots from a Glock, Škorpion vz. 61, and AK-47, but was penetrated by the Dragunov sniper rifle. Increasing the depth of the stainless steel to at least a centimeter of ballistic grade steel may have helped protect the plate from higher calibers, but [PrepTech] explained that he wasn’t able to obtain the material in his country.

Nevertheless, the lower calibers were still unable to puncture even the steel, so unless you plan on testing out the plate on high caliber weapons, it’s certainly a success for low-cost defense tools.

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The Hacker History Of Music Technologies

January 6, 2020 by 7 Comments

Music throughout history has been inspired and changed by hackers and makers, and never moreso than in the 20th century. Helen Leigh is one such hacker, who brought a talk to Supercon to give us a crash course in the history of recording, electronics and music, and what the maker movement is doing in the music world today.

The tape recorder was an invention that kicked off a golden period of exploration in sound. Beginning in World War II, the Nazi propaganda machine cut and spliced recorded materials and disseminated them across broadcasting stations in Europe. To the astonishment of the Allies, certain German officials appeared to be making broadcasts from different studios at the same time, due to the high quality of the recording hardware. After the war, this technology was discovered by a group of Parisian recording artists who began to experiment with an art that became known as musique concrète, using tape hardware in weird and wonderful ways to create new sounds heretofore unheard in nature.

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AirBass Lets You Jam Wherever

January 5, 2020 by 11 Comments

If you play an instrument, you know how rewarding it is to watch and hear yourself reproduce your favorite songs and make new melodies. But you also know how steep the learning curve can be, how difficult it is to learn positions and notes while your body adjusts to the physical side. For stringed instruments, that means gaining muscle memory, growing fingertip calluses, and getting used to awkward arm positions.

For their final project in [Bruce Land]’s class on designing with microcontrollers, [Caitlin, Jackson, and Peter] decided to make a more accessible bass guitar. For starters, it can be placed flat on a table similar to a pedal steel guitar to get around those awkward arm positions. Instead of plucking or slapping the strings, the player wears a glove with a flex resistor on each finger, and plays the string by curling and uncurling their finger.

We think the team’s implementation of the left hand duties and fretboard is pretty clever. Each of the four strings has a break-beam detection circuit, and a single distance sensor decides where the finger is along the fretboard. Another great thing about this backpack-sized bass is that it never needs tuning. If you stay tuned, you can hear [Peter] play “Smoke On the Water” after the break.

There’s more than one way to make an air guitar — this one that does it with LIDAR.

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Giving Sight To The Blind With A Wave Of The Hand

November 6, 2019 by 1 Comment

[Jakob Kilian] is working on a glove that he hopes will let the blind “see” their surroundings.

One of the most fascinating examples of the human brain’s plasticity is in its ability to map one sense to another. Some people, for example, report being able to see sound, giving them a supernatural ability to distinguish tones. This effect has also been observed in the visually impaired. There are experiments where grids of electrodes were placed on the tongue or mechanical actuators were placed on the lower back. The signals from a camera were fed into these grids and translated in to shocks or movement. The interesting effect is that the users quickly learned to distinguish objects from this low resolution input. As they continued to use these devices they actually reported seeing the objects as their visual centers took over interpreting this input.

Most of these projects are quite bulky and the usual mess you’d expect from a university laboratory. [Jakob]’s project appears to trend to a much more user-friendly product. A grid of haptics are placed on the back of the user’s hand along with a depth camera. Not only is it somewhat unobtrusive, the back of the hand is very sensitive to touch and the camera is in a prime position to be positioned for a look around the world.

[Jakob] admits that, as an interaction designer, his hardware hacking skills are still growing. To us, the polish and thought that went into this is already quite impressive, so it’s no wonder he’s one of the Hackaday Prize Finalists.

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