Simple Tactile Drawing Pad Is Quite Impressive

August 31, 2021 by Kristina Panos 5 Comments

Everyone needs to be able to communicate and express themselves, even people with blindness or low vision. Embossing paper with some kind of stylus is a popular, low-tech option, but there’s one big problem: pressing paper from the top leaves a dent, and so letters have to either be written backwards or else felt-read backwards. For this year’s Hackaday Prize, [Subir Bhaduri] is working on a fantastic tool that embosses positively, and from the top side of the paper.

Here’s how it works: a pointed stylus pushes upward from the underside and meets up with a concave receiver on the top side through the paper. The two stylii move in concert thanks to the pantograph-inspired parallelogram setup, which we imagine would make it easier for someone with low vision to keep their bearings as they move around the page.

The video below shows prototype #2, which is the first one that worked. Well, it works, but [Subir] says it needs improvement, so prototype #3 is in the sketching stage now. [Subir] is planning to fix the paper in place somehow and also figure out how to keep the pantograph arms out of the user’s way.

Pantographs are used for all sorts of things, but the sweetest use we’ve seen was to carve messages into chocolate hearts.

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Calculate Like It’s 1989 With This HP15C Emulator

August 31, 2021 by Dan Maloney 41 Comments

Back in the day, your choice of calculator said a lot about your chops, and nothing made a stronger statement than the legendary Hewlett-Packard Voyager series of programmable calculators. From the landscape layout to the cryptic keycaps to the Reverse Polish Notation, everything about these calculators spoke to a seriousness of purpose.

Sadly, these calculators are hard to come by at any price these days. So if you covet their unique look and feel, your best bet might be to do like [alxgarza] and build your own Voyager-series emulator. This particular build emulates the HP15C and runs on an ATMega328. Purists may object to the 192×64 LCD matrix display rather than the ten-digit seven-segment display of the original, but we don’t mind the update at all. The PCB that the emulator is built on is just about the right size, and the keyboard is built up from discrete switches that are as satisfyingly clicky as the originals. We also appreciate the use of nothing but through-hole components — it seems suitably retro. The video below shows that the calculator is perfectly usable without a case; a 3D-printed case is available, though, as is an overlay that replicates the keypad of the original.

We’ve seen emulators for other classic calculators of yore, including Sinclair, Texas Instruments, and even other HP lines. But this one has a really nice design that gets us going.

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Ten Winners Of The Hackaday Prize Supportive Tech Challenge

August 31, 2021 by Mike Szczys 5 Comments

Congratulations to the ten projects that have been selected to receive $500, and continue to the finals of the 2021 Hackaday Prize! Each of these are a different take on the Reimagine Supportive Tech Challenge that sought ways to make great hardware ideas work for more people.

Ebooks have made it possible for everyone to have a library in their pocket, and that has included the visually impaired as text-to-speech can read the printed word. But that’s not a complete replacement for reading for yourself and so the Thenar steps in as an affordable, portable braille ebook reader. It leverages a single braille cell on the edge of the device, and a tank-track-style scroll wheel for user input. Complete with a docking station to inductively charge the battery, it’s a high-end reader for those who need an alternative to epaper.

Okay, pop-quiz; how many of us want to have a future involving solar-powered everything? Most of us now have our hands up, but how many of us can set up a high-efficiency solar charge controller ourselves? If this next finalist (pictured at the top) has its way the answer will be just about everyone. The 2.5 kilowatt solar generator in a rugged brief case is packing a whopping 160 (!) 18650 lithium cells. The charging side of the design handles the maximum power-point tracking (MPPT) while the discharging side protects the user with a circuit breaker and all kinds of regulated outputs like 120 V, 24 V, 12 V, and of course all of the USB-C functionality you’d expect from a system like this.

Ten Finalists, Eight Dozen Entries

We cherry-picked two excellent finalists above, but all ten of these are easily worth their own mention (and many have already been individually featured on these pages). Congrats to the folks who will be headed to the finals in October!

It was a tight field of nearly 100 entries for this round, make sure to take some time to check those out and offer kudos in the comment sections of each project. We’re excited to see what comes of the robotics-oriented challenge currently underway!

Mice with capactive sensors instead of buttons. Designed for people with low mobility.

Capacitive Mouse Built For A Friend Makes For A Touching Tale

August 30, 2021 by Kristina Panos 26 Comments

Those tiny switches inside your mouse may be rated for 50 million clicks or more, but your fingers will likely wear out much sooner than that. Trust us — mouse arm and/or hand fatigue is no fun at all. If you’ve never had the displeasure, just try to imagine not being able to click or move the mouse around without extreme discomfort.

For this year’s Hackaday Prize, [BinSun] hacked together a capacitive mouse for a friend who has ALS. Instead of micro switches, it uses touch sensors to detect left and right clicks and LEDs to indicate when a click has taken place. That makes us think that haptic feedback could be cool, but it might get old quickly, or even worse, you might get used to it after a while and not feel it anymore.

This mouse would be a good alternative for anyone with limited mobility from any condition — ALS, arthritis, trigger finger, or carpal/cubital tunnel syndrome. It would also benefit anyone who wants to mouse much more stealthily, like in a library, a small shared space, or late at night. The only downside we can see is that you’d either have to get used to hovering your fingers, or else learn to rest them out of the way of the capacitive buttons. Otherwise, you’re gonna actuate them more often than you really want to.

If you want to build one of these, you’ll find a nice set of instructions over on IO that includes the minor modifications necessary to make the TTP223 capacitive modules sensitive enough to detect the presence of a finger. All you really have to do is bridge a couple of pads, add a capacitor and remove the SMD LEDs. [Bin Sun] says this is an ongoing project. He’s gotten a handful of beta testers involved at this point, and is planning to make a dedicated PCB pretty soon. Squeak past the break for a couple of brief demonstrations.

The right kind of mouse can save your limbs, sure. Hack together a different type of mouse, and you might be able to save your crops from elephant raids.

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Binary Clock Lets The Nixies Glow

August 28, 2021 by Brian McEvoy 2 Comments

We’re not here to talk about another clock. Okay, we are, but the focus isn’t about whether or not it can tell time, it’s about taking a simple idea to an elegant conclusion. In all those ways, [Marcin Saj] produced a beautiful project. Most of the nixie clocks we see are base-ten, but this uses base-two for lots of warm glow from more than a dozen replaceable units.

There are three rows for hours, minutes, and seconds. The top and bottom rows are labeled with an “H” and “S” respectively displayed on IN-15B tubes, while the middle row shows an “M” from an IN-15A tube. The pluses and minuses light up on IN-12 models so you’ll need eighteen of them for the full light show, but you could skimp and use sixteen in twelve-hour mode since you don’t need to count to twenty-four. We won’t explain how to read time in binary, since you know, you’re here and all. The laser-cut acrylic is gorgeous with clear plastic next to those shiny nixies, but you have to recreate the files or buy the cut parts as we couldn’t find vector files amongst the code and schematics.

Silly rabbit, nixies aren’t just for clocks. You can roll your own, but they’re not child’s play.

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image of two floor lamps, one cool and one hot,

Customized Work-From-Home Lighting

August 27, 2021 by Chris Lott 7 Comments

[Jon] wants his home office lighting to mimic the light outside, at least from a color perspective. To that end, he has embarked on a design which monitors both the outdoor light and at his work station, and accordingly drives a pair of LED lamps of different colors. One lamp is rated at above 5000 K and provides “cool” lighting, , and the other is rated at less than 3000 K for “warm” lighting.

Commercial solutions do exist, but they are proprietary and do this within a single bulb and seem difficult to control in an orchestrated manner throughout the house. [Jon] plans for his approach to be scalable, eventually consisting of a variety of lighted areas of the house from a single microcontroller.

One of the design goals for this project is to create something that could disappear into the room, rather than the science fair aesthetic of my prior project.

One commenter on his project’s site asked why [Jon] is doing this, that is, what is the value of controlling the color of your indoor lighting? While [Jon] doesn’t have a specific goal in mind at the moment, he notes that these techniques could potentially be helpful for enhancing productivity, managing circadian rhythms, and as light therapy for seasonal depression.

We covered [Jon]’s science-fair-like project that in this writeup from last year. If the topic interests you, check out the white papers he links on his project page for further reading.

Universal Bio-Electrical Signal Amplifier Makes Reading Body Signals Easy

August 26, 2021 by Robin Kearey 18 Comments

The electrical signals emitted by the human body tell us a lot about what’s going on inside. But getting those signals inside your microcontroller is not straightforward: the voltages are too small for most ADCs, and the ever-present 50 or 60 Hz mains frequency makes it hard to discern subtle changes. Over at Upside Down Labs, [Deepak Kathri] developed a universal biosensor interface called the BioAmp EXG Pill to make all this a lot easier.

Its name refers to the fact that it can be used for several different bio-electrical sensing applications: ECG, EMG, EOG and EEG, which deal with signals coming from the heart, muscles, eyes and brain, respectively. To enable such flexibility, the board has connectors for two or three electrodes, as well as solder pads to mount resistors and capacitors to adjust the gain and bandwidth. An instrumentation amplifier increases the strength of the desired signal while rejecting noise and interference.

The form factor allows easy connection to electrodes on one side and a data acquisition system on the other. Measuring just 25.4 mm long and 10 mm wide, it should be easy to integrate into any type of biosensing gizmo you can come up with. [Deepak] has made several demo setups, showing him using the Pill with an Arduino to measure his heart rate, detect eye blinks, and even control a robot arm using his own arm muscles!

The EXG Pill is an evolution of an earlier EMG-only project. We’ve seen several great ECG and EEG projects before, but is the first time we’ve seen one amplifier that can do them all.