Year: 2017

Interactive Game Board Helps Toddler Learn Colors And Shapes

February 26, 2017 by 10 Comments

Most parents would do anything to enrich their kids’ worlds and teach them what they need to know. Hacker parents often take it one step further by modifying the kid’s world to allow them to work past a disability. To wit we have an interactive game board to help a toddler learn her shapes and colors.

The toddler in question is [Becca], and her needs are special because of the progressive nature of the blindness that will result from her Usher Syndrome. [Becca] will need visual acuity testing much earlier than most toddlers, but a standard eye chart is meaningless to kids before they get their letters. This is where Lea shapes come in – a set of four shapes that are used to make visual testing a game and help practitioners assess what a child can and cannot see.

[Jake] and his wife [Beth] were advised to familiarize [Becca] with the shapes, but all she wanted to do was eat the printed sheet. In order to make the task more entertaining, [Jake] built an interactive board where brightly colored Lea shapes trigger the room lights to change to the same color as the block when it’s inserted into the correct spot on the board, as a visual reward. Reed switches, magnets, and an Arduino comprise the game logic, and the board communicates to the Philips Hue smart bulbs over an NRF24L01. The video below also shows some cool under-bed lights and a very engaged [Becca] learning her shapes and colors.

As we expected when we last covered his efforts to help [Rebecca], [Jake] has leveraged the Raspberry Pi he used as a hub for the stairwell lighting project. We’re looking forward to seeing what else he comes up with, and to see how [Becca] is thriving.

Continue reading “Interactive Game Board Helps Toddler Learn Colors And Shapes” →

How’d They Do It: Levitating Orb Clock

February 26, 2017 by 72 Comments

It’s time for everyone’s favorite game: speculative engineering! An anonymous reader wrote to our tips line asking how the levitation system of the STORY clock is accomplished. We took a look and can tell you right now… that’s a really good question!

STORY: The Levitating Timepiece has more than a month left on its crowdfunding campaign but it’s reached more than 6x its $80k goal. The wooden disk has a digital time display in the center which is simply an LED matrix just below the wood’s surface. We know how that’s done: wooden veneer with a grid of holes behind to contain the LED light in a perfect circle. Continue reading “How’d They Do It: Levitating Orb Clock” →

Loop Antenna Is Portable

February 25, 2017 by 15 Comments

We don’t know if [OH8STN] has a military background, but we suspect he might since his recent post is about a “DIY Man Portable Magnetic Loop Antenna.” “Man-portable” is usually a military designation, and — we presume — he wouldn’t object to a woman transporting it either.

[OH8STN] started with a Chameleon antenna starter kit. This costs about $100 and is primarily a suitable variable capacitor with a 6:1 reduction drive premounted and soldered. Of course, you could source your own, but finding variable capacitors that can handle transmit duty (admittedly, these can apparently handle about 10 W continuous or 25 W on single sideband) can be tricky, especially these days. Although he started with a kit, he did modify the antenna to switch between two different sets of ham radio bands. You can see the antenna in the video below.

Loop antennas aren’t ideal–but neither is any other small antenna. Because the loop is tightly tuned to a particular frequency, it requires retuning for even relatively small frequency changes, even though it can operate on many different frequencies. If you want more technical details, you might enjoy this recent presentation from [W4RAX]. The links at the end are worth checking out, too.

Continue reading “Loop Antenna Is Portable” →

Decorate Your 3D Prints With Detailed Hydrographic Printing

February 25, 2017 by 19 Comments

It’s like the old quip from [Henry Ford]: You can have your 3D prints in any color you want, as long as it’s one. Some strides have been made to bringing more color to your extruded goodies, but for anything beyond a few colors, you’re going to need to look at post-print processing of some sort. For photorealistic 3D prints, you might want to look into a simple hydrographic printing method that can be performed right on a printer.

If some of the prints in the video below look familiar, it’s because we covered the original method when it was presented at SIGGRAPH 2015. [Amos Dudley] was intrigued enough by the method, which uses computational modeling of complex surfaces to compose a distorted image that will be stretched back into shape when the object is dipped, to contact the original authors for permission to use the software. He got a resounding, “Nope!” – it appears that the authors’ institution isn’t big into sharing information. So, [Amos] hacked the method.

In place of the original software, [Amos] used Blender to simulate the hydrographic film as a piece of cloth interacting with the 3D-printed surface. This allowed him to print an image on PVA film that will “un-distort” as the object is dipped. He built a simple tank with overflow for the printer bed, used the Z-axis to dip the print, and viola! Photo-realistic frogs and globes.

[Amos]’ method has its limitations, but the results are pretty satisfying already. With a little more tweaking, we’re sure he’ll get to the point that the original authors did, and without their help, thank you very much.

Continue reading “Decorate Your 3D Prints With Detailed Hydrographic Printing” →

Octosonar Is 8X Better Than Monosonar

February 25, 2017 by 29 Comments

The HC-SR04 sonar modules are available for a mere pittance and, with some coaxing, can do a pretty decent job of helping your robot measure the distance to the nearest wall. But when sellers on eBay are shipping these things in ten-packs, why would you stop at mounting just one or two on your ‘bot? Octosonar is a hardware and Arduino software library that’ll get you up and running with up to eight sonar sensors in short order.

Octosonar uses an I2C multiplexer to send the “start” trigger pulses, and an eight-way OR gate to return the “echo” signal back to the host microcontroller. The software library then sends the I2C command to select and trigger a sonar module, and a couple of interrupt routines watch the “echo” line to figure out the time of flight, and thus the distance.

Having two sonars on each side of a rectangular robot allows it move parallel to a wall in a straightforward fashion: steer toward or away from the wall until they match. Watch the video below for a demo of this very simple setup. (But also note where the robot’s 45-degree blind spot is: bump-bump-bump!)

Continue reading “Octosonar Is 8X Better Than Monosonar” →

Do You Trust Your Hard Drive Indication Light?

February 25, 2017 by 48 Comments

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?” →

Ask Hackaday: Bitten By The Crocodile Clip

February 25, 2017 by 69 Comments

I have a love/hate relationship with the crocodile clip. Nothing is so quick to lash together a few half-baked prototype boards on your desk, but nothing ends up in such a tangle so quickly, either. I love the range of pretty colors that crocodiles come in, as well as the easy ability to just clip on to the side of a PCB, or any old loose wire. But they come loose, they can have intermittent contacts, and we’re not even sure if there is such a thing as a current rating for them.

When [WarriorRocker] wrote in asking what we use instead of crocodile clips, he included a photo that sent a chill down my spine, from a review of some clips on Amazon. I’ve seen this one in real life. And what’s worse is the one with the loose wires that sometimes make contact with the spring-clip body and sometimes not.

After an hour-long debugging session about twelve years ago now, such an intermittent croc caused us to make a lifelong vow. All of our croco-clips have been disassembled, manually inspected, and many of them soldered together. When I buy new ones, I check them all before mixing them in with the known-goods. Even thinking about this now makes me want to pull back their little rubber booties just to make sure. Continue reading “Ask Hackaday: Bitten By The Crocodile Clip” →