E-Book Reader Gets Page Turn Buttons, Is None The Wiser

July 4, 2019 by Donald Papp 13 Comments

Most e-book readers don’t have physical page turn buttons. Why? They just don’t. Virtual page turns are accomplished with a tap at a screen edge. Determined to reduce the awkwardness of one-handed use, [Sagar Vaze] modified a Kobo e-reader with two physical page turn buttons as a weekend project.

[Sagar] points out that since the underlying OS of the Kobo device is Linux, it is possible to fake touches to the screen (and therefore trigger page turns) by recording then replaying the appropriate input event. However, there was a more direct solution available to those willing to tamper slightly with the hardware. Touch sensing on the screen is done via an infrared break-beam system. Along two edges of the screen are IR emitters, and opposite the emitters are receivers. Broadly speaking, when a fingertip touches the display a minimum of two IR beams are broken, and the physical location of the fingertip can therefore be determined by analyzing exactly how the IR pattern has been changed.

To spoof page turns, [Sagar] briefly shorts two IR emitters: one on each axis. The sudden winking out of the IR is interpreted by the device as a crisp tap, and the device obediently turns the page. The only hitch is that both IR emitters must be shorted at the same time. If one is shorted before the other, the device ignores it. Double-pole switches would probably do the trick, but with the part bin coming up empty in that respect, [Sagar] instead used a few transistors to accomplish the same thing. A 3D printed enclosure rounds out the whole mod, and a brief video is embedded below.

Continue reading “E-Book Reader Gets Page Turn Buttons, Is None The Wiser” →

The ArduBoy Community Rolled Their Own Cartridge

June 7, 2019 by Tom Nardi 10 Comments

The Arduboy, as you might have guessed from the name, was designed as a love letter to the Nintendo Game Boy that many a hacker spent their formative years squinting at. While the open source handheld is far smaller than the classic DMG-01, it retains the same general form factor, monochromatic display, and even the iconic red LED to the left of the screen. But one thing it didn’t inherit from the original was the concept of removable game cartridges. That is, until now.

Over the last year, [Mr.Blinky] and a group of dedicated Arduboy owners have been working on adding a removable cartridge to the diminutive handheld. On paper it seemed easy enough, just hang an external SPI flash chip off of the test pads that were already present on the Arduboy PCB, but to turn that idea into a practical cartridge required an immense amount of work and discussion. The thread on the Arduboy community forums covers everything from the ergonomics of the physical cartridge design to the development of a new bootloader that could handle loading multiple games.

The first problem the group had to address was how small the Arduboy is: there’s simply no room in the back to add in a cartridge slot. So a large amount of time is spent proposing different ways of actually getting the theoretical cartridge attached to the system. There was some talk of entirely redesigning the case so it could take the cartridge internally (like the real Game Boy), but this eventually lost out for a less invasive approach that simply replaced the rear of the Arduboy with a 3D printed plate that gave the modders enough room to add a male header along the top edge of the system.

As an added bonus, the cartridge connector doubles as an expansion port for the Arduboy. While perfecting the design, various forum users have chimed in with different gadgets that make use of the new port, from WS2812B LEDs to additional input devices like joysticks or a full QWERTY keyboard. Even if you aren’t interested in expanding the storage space on your Arduboy, being able to plug in new hardware modules certainly opens up some interesting possibilities.

In fact, the project so impressed Arduboy creator [Kevin Bates] that he chimed in on the topic last month to announce he would start looking into integrating the community’s cartridge modification into the production hardware. If all goes well, pretty soon there might be an official upgrade path for those who want to expand what this tiny nostalgia machine is capable of.

Continue reading “The ArduBoy Community Rolled Their Own Cartridge” →

One Arduino Handheld To Rule Them All

May 28, 2019 by Tom Nardi 9 Comments

There’s nothing quite as annoying as duplicated effort. Having to jump through the same hoops over and over again is a perfect way to burn yourself out, and might even keep you from tackling the project that’s been floating around in the back of your mind. [Alain Mauer] found that he’d build enough Arduino gadgets that were similar enough he could save himself some time by creating a standardized piece of hardware that he can load his code du jour on.

He’s come to call this device the Arduino Nano QP (which stands for Quick Project), and now it’s part of the 2019 Hackaday Prize. [Alain] doesn’t promise that it’s the perfect fit for everything, but estimates around 85% of the simple Arduino projects that he’s come up with could be realized on QP. This is thanks to the screw terminals on the bottom of the device which let you easily hook up any hardware that’s not already on the board.

The QP board itself has the ubiquitous 16×2 character LCD display (complete with contrast control trimmer), seven tactile buttons arranged in a vaguely Game Boy style layout, and of course a spot to solder on your Arduino Nano. All of which is protected by a very slick laser cut acrylic case, complete with retained buttons and etched labels.

We’ve seen no shortage of handheld Arduino devices, but we have to admit, something about the utilitarian nature of this one has us intrigued. We wouldn’t mind having one of these laying around the lab next time we want to do a quick test.

Continue reading “One Arduino Handheld To Rule Them All” →

Building An ESP8266 Game System With MicroPython

May 16, 2019 by Tom Nardi 6 Comments

After a seemingly endless stream of projects that see the ESP8266 open doors or report the current temperature, it can be easy to forget just how powerful the little WiFi-enabled microcontroller really is. In fact, you could argue that most hackers aren’t even scratching the surface of what the hardware is actually capable of. But that’s not the case for [Brian Wagner] and his students from the Kentucky Country Day School.

Their project, the GamerGorl, is a completely custom handheld game system running on a Wemos D1 Mini development board. The team’s PCB, which was developed over several iterations, is essentially a breakout board which allows them to easily connect up peripheral devices. Given the low total component cost of the GamerGorl and relative simplicity of its construction, it looks like a phenomenal project for older STEM students.

Beyond the ESP8266 board, the GamerGorl features a SSD1106 1.3″ OLED display, a buzzer for sound effects, two tactile buttons, and an analog joystick originally intended for an Xbox controller. Around the backside there’s a WS2812B RGB LED strip that’s at least partially for decoration, but it’s also actively used in some of the games such as the team’s take on Simon.

Even if you aren’t in the market for a portable game system, the GameGorl does provide an interesting case study for MicoPython applications on the Wemos D1 Mini. Browsing through the team’s source code as well as the helpful hints that [Brian] gives about getting the software environment up and running could be useful if you’re looking to expand your ESP8266 programming repertoire. We’d also love to see this device running the “ESP Little Game Engine” we covered recently.

Continue reading “Building An ESP8266 Game System With MicroPython” →

A Keyboard For Your Thumb

March 26, 2019 by Brian Benchoff 11 Comments

Here’s an interesting problem that no one has cracked. There are no small keyboards that are completely configurable. Yes, you have some Blackberry keyboards connected to an Arduino, but you’re stuck with the key layout. You could get one of those Xbox controller chat pads, but again, you’re stuck with the keyboard layout they gave you. No, the right solution to building small and cheap keyboards is to make your own, and [David Boucher] has the best one yet.

The Thumb Keyboard uses standard through-hole 4mm tact switches on a 10×4 grid, wired up in a row/column matrix. Yes, this is a mechanical keyboard, which is important: no one wants those terrible rubber dome keyswitches, and you need only look at the RGB gaming keyboard market for evidence of that. These tact switches fit into a standard perfboard, allowing anyone to build this at home with a soldering iron. After wiring up the keyboard and connecting it to an Arduino, [David] had a working keyboard.

There’s a lot going on with this build, not the least of which is the custom, 3D printed bezel for those tiny, tiny tact switches. This is a much simpler solution than building an entirely new PCB, which we’ve seen before. Since this is a 3D printed bezel, it’s easy to put labels or whatnot above the keys, or potentially print buttons. It’s great work, and one of the best small keyboards we could imagine.

Repairing A Vintage Sharp MemoWriter

March 26, 2019 by Tom Nardi 9 Comments

As you may know, we’re rather big fans of building things here at Hackaday. But we’re also quite partial to repairing things which might otherwise end up in a landfill. Especially when those things happen to be interesting pieces of vintage hardware. So the work [ekriirke] put in to get this early 1980’s era Sharp MemoWriter EL-7000 back up and running is definitely right up our alley.

There were a number of issues with the MemoWriter that needed addressing before all was said and done, but none more serious than the NiCd batteries popping inside the case. Battery leakage is a failure mode that most of us have probably seen more than a few times, but it never makes it any less painful to see that green corrosion spreading over the internals like a virus. When [ekriirke] cracked open this gadget he was greeted with a particularly bad case, with a large chunk of the PCB traces eaten away.

The corrosion was removed with oxalic acid, which dropped the nastiness factor considerably, but didn’t do much to get the calculator back in working order. For that, [ekriirke] reconnected each damaged trace using a piece of wire; he even followed the original traces as closely as possible so the final result looked a little neater. Once everything was electrically solid again, he covered the whole repair with a layer of nail polish to adhere the wires and add a protective coating. Nail polish might not have been our first choice for a sealer, and likely not that particular shade even if it was, but sometimes you’ve got to use what you have on hand.

After years of disuse the ribbon cartridge was predictably dry, so [ekriirke] rejuvenated it with the fluid from a permanent marker applied to the internal sponge. He also made some modifications to the battery compartment so he could insert rechargeable Ni-MH AA batteries rather than building a dedicated pack. There’s no battery door in the enclosure, so removing the batteries will require opening the calculator up, but at least he has the ability to remove the batteries before putting the device in storage. Should help avoid a repeat of what happened the first time.

If you’re a fan of a good restoration, we’ve got plenty to keep you entertained. From bringing a destroyed Atari back from the dead to giving some cherished children’s toys a new lease on life, fixing old stuff can be just as engrossing as building it from scratch.

Continue reading “Repairing A Vintage Sharp MemoWriter” →

Tucoplexing: A New Charliplex For Buttons And Switches

March 23, 2019 by Kerry Scharfglass 28 Comments

Figuring out the maximum number of peripherals which can be sensed or controlled with a minimum number of IOs is a classic optimization trap with a lot of viable solutions. The easiest might be something like an i2c IO expander, which would give you N outputs for 4 wires (SDA, SCL, Power, Ground). IO expanders are easy to interface with and not too expensive, but that ruins the fun. This is Hackaday, not optimal-cost-saving-engineer-aday! Accordingly there are myriad schemes for using high impedance modes, the directionality of diodes, analog RCs, and more to accomplish the same thing with maximum cleverness and minimum part cost. Tucoplexing is the newest variant we’ve seen, proven out by the the prolific [Micah Elizabeth Scott] (AKA [scanlime]) and not the first thing to be named after her cat Tuco.

[Micah’s] original problem was that she had a great 4 port USB switch with a crummy one button interface. Forget replacement; the hacker’s solution was to reverse and reprogram the micro to build a new interface that was easier to relocate on the workbench. Given limited IO the Tucoplex delivers 4 individually controllable LEDs and 4 buttons by mixing together a couple different concepts in a new way.

Up top we have 4 LEDs from a standard 3 wire Charlieplex setup. Instead of the remaining 2 LEDs from the 3 wire ‘plex at the bottom we have a two button Charlieplex pair plus two bonus buttons on an RC circuit. Given the scary analog circuit the scan method is pleasingly simple. By driving the R and T lines quickly the micro can check if there is a short, indicating a pressed switch. Once that’s established it can run the same scan again, this time pausing to let the cap charge before sensing. After releasing the line if there is no charge then the cap must have been shorted, meaning that switch was pressed. Else it must be the other non-cap switch. Check out the repo for hardware and firmware sources.

Last time we talked about a similar topic a bunch of readers jumped in to tell us about their favorite ways to add more devices to limited IOs. If you have more clever solutions to this problem, leave them below! If you want to see the Twitter thread with older schematics and naming of Tucoplexing look after the break.

Continue reading “Tucoplexing: A New Charliplex For Buttons And Switches” →