Pocket Computer Reminds Us Of PDAs

June 23, 2022 by Bryan Cockfield 9 Comments

Before smartphones exploded on the scene in the late 00s, there was still a reasonable demand for pocket-sized computers that could do relatively simple computing tasks. Palm Pilots and other PDAs (Personal Digital Assistants) were all the rage in the ’90s and early ’00s, although for cutting-edge tech from that era plenty of these devices had astronomical price tags. This Arduino-based PDA hearkens back to that era, albeit with a much more accessible parts list.

The build is based around an Arudino Nano with an OLED screen and has the five necessary functions for a PDA: calculator, stopwatch, games, phonebook, and a calendar. With all of these components on such a small microcontroller, memory quickly became an issue when using the default libraries. [Danko] uses his own custom libraries in order to make the best use of memory which are all available on the project’s GitHub page. The build also includes a custom PCB to keep the entire pocket computer pocket-sized.

There are some other features packed into this tiny build as well, like the breakout game that can be played with a potentiometer. It’s an impressive build that makes as much use of the microcontroller’s capabilities as is possible, and if you enjoy projects where a microcontroller is used as if it is a PC take a look at this Arduino build with its own command-line interface.

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3D Print A Colour TV

May 27, 2022 by Jenny List 36 Comments

The oldest form of television used a spinning disk with a progression of holes — a Nipkow disk — to slice the image into lines for display. They’re surprisingly simple machines and capable of unexpectedly high-quality images despite their relatively low resolution. Even better, in an age of microcontrollers and bright LEDs, making one that works is not the chore it might once have been. [Markus Mierse] has created one that uses an Arduino Mega and a set of 3D printed parts, so there’s no excuse for not having a spinning disk TV on your shelf.

The Arduino Mega is chosen because it has enough lines to drive three six-bit DACs for each of red, green, and blue. The disk is driven by a PWM motor controller, and synchronization is taken care of by a piece of reflective tape and an IR proximity sensor. Images and video are read from an SD card and displayed on the screen in glorious 32-line colour. The full build process can be seen in the video below the break.

A surprise when viewing mechanical TV is that its quality is much better than the meager resolution would have you believe, and this one with its colour display is much better than the usual monochrome devices. It’s hardly HDTV, but it acquits itself well and would provide an excellent talking point.

If you’re curious about Nipkow disks, they’re a subject we’ve examined in the past.

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Sisyphean Ball Race Robot Toils Gracefully, Magnetically

May 20, 2022 by Kristina Panos 5 Comments

Aren’t ball races and marble runs fun? Wouldn’t they be so much more enjoyable if you didn’t have to climb back up the ladder each time, as it were, and reset the thing? [Johannes] wrote in to tell us about a wee robot with the Sisyphean task of setting a ball bearing on a simple but fun course, collecting it from the end, and airlifting it back to the start of the track.

[Johannes] built this ‘bot to test small-scale resin printing strength as well as the longevity of some tiny linear actuators from Ali that may or may not be available at a moment’s notice. The point was to see how these little guys fared when connected directly to an Arduino or other microcontroller, rather than going the safer route with a motor driver of some kind.

Some things worked well, like the c-clips that keep the axles together, and using quick pulses to release the magnetically-linked ball from the gripper. Other aspects didn’t work out so well. Tiny resin parts do not respond well to force, for starters. And then there’s the actuators themselves. The connections are fragile and the motors are weak, but they vary wildly in quality from piece to piece, so YMMV. Some lose steps, and others occasionally seize. But you wouldn’t know any of that from the graceful movement capture in the video below. Although it appears to be automated, the bot is under remote control because of the motor issues.

Not into ball runs? There are other Sisyphean tasks available, such as moving sand around in the name of meditation.

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Hacking The Logitech Z906 Speaker System

May 19, 2022 by Lewin Day 42 Comments

The Logitech Z906 is a well-rounded 5.1 surround sound system. It’s capable of putting out 1000W in peak power, and can decode Dolby Digital and DTS soundtracks as you’d expect. It’s intended to be used as the heart of a home cinema system and used with a central command console. However, [zarpli] figured out the device’s serial secrets and can now run the device in a standalone manner.

As it turns out, the Z906 uses a main control console that speaks to the rest of the hardware over a DE15 connector (also known as the DB-15). [zarpli] realized that the hardware could instead be commanded by just about any device with a serial port. Thus, a library was whipped up that can be readily used with an Arduino to control all the major functions of the Z906. Everything from volume levels to effect modes and channel assignments can be commanded by microcontroller. As a finale, [zarpli] shows off the hardware playing a multi-channel composition without the console connected, with his own hardware running the show instead.

If you’ve got a Logitech Z906 or similar unit that you wish to automate, you might find this work useful. It’s also a good inspiration for anyone contemplating hacking away at the console ports on other hardware. Video after the break.

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Water Your Plants Just Four Times Per Year

May 19, 2022 by Kristina Panos 20 Comments

While it’s true that some plants thrive on neglect, many of them do just fine with a few ounces of water once a week, as long as the light level is right. But even that is plenty to remember and actually do in our unprecedented times, so why bother trying? [Martin] has solved this problem for us, having given every aspect of automatic plant care a lot of thought. The result of his efforts is Flaura, a self-watering open-source plant pot, and a YouTube channel to go with it.

The 3D-printed pot can easily be scaled up or down to suit the size of the plant, and contains a water reservoir that holds about 0.7 L of water at the default size. Just pour it in through the little spout, and you’re good for about three months, depending on the plant, the light it’s in, and how much ~~current~~ water it draws. You can track the dryness level in the companion app.

Whenever the capacitive soil moisture sensor hidden in the bottom of the dirt detects drought conditions, it sends a signal through the Wemos LOLIN32 and a MOSFET to a small pump, which sends up water from the reservoir.

The soil is watered uniformly by a small hose riddled with dozens of tiny holes that create little low-pressure water jets. This is definitely our favorite part of the project — not just because it’s cool looking, but also because a lot of these types of builds tend to release the water in the same spot all the time, which is. . . not how we water our plants. Be sure to check out the project overview video after the break.

No printer? No problem — you could always use an old Keurig machine to water a single plant, as long as the pump is still good.

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Summer’s Coming – Let Mowerino Cut Your Grass

May 11, 2022 by Al Williams 22 Comments

In the Northern hemisphere, summer is about to hit us full bore. While we love the season, we do dislike lawn maintenance. Apparently, so does [salmec] who developed the Mowerino around an Arduino Mega 2560 board.

As you might expect, the robot uses sharp blades so, you probably want to be careful. There are sensors that allow the machine to self-navigate or you can control it via Bluetooth. This is one of those things that seems easy until you try to actually do it. Nylon trimmer string is probably safer, but it breaks and it is hard to keep it cutting. Blades are more robust but also riskier to things like rocks, fingers, and pets.

Moving around in the yard is also an issue. The Mowerino has some ordinary-looking caster wheels in the front. That might be a place for improvement since most yards are not friendly to that kind of wheel. The other thing we worried about is what happens to the grass clippings. Around here, a week of rain means your mower will choke on grass clippings. On the other hand, the Mowerino has a smaller blade so maybe that helps mitigate clipping clogging.

Overall, though, it looks like it might be a good place to start if you dream of robot groundskeepers patrolling your estate. Most of the mowers we see like this have big wheels. But, of course, not all of them.

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Stop-Motion Angels In The Light Field

May 3, 2022 by Matthew Carlson No comments

Baseball jokes aside, holograms have been a dream for decades, and with devices finally around that support something like them, we have finally started to wonder how to make content for them. [Mike Rigsby] recently entered his stop-motion holographic setup into our sci-fi contest, and we love the idea.

Rather than a three-dimensional model or a 2d picture with pixels, the Looking Glass light field display supports a series of images as quantized points (hence light field). As you move around an object, images are interpolated between the frames you do know, giving a pretty convincing effect. In a traditional stop motion animation, you need to take anywhere between 12-24 frames to equal about one second of animation. Now that you need to take 48 pictures for one frame, over 1152 pictures for just one second of animation. Two problems quickly appear, how to take photographs accurately from the same position every time and how do you manage the deluge of photos sensibly. [Mike] started with a wooden stage for his actors. A magnet was mounted to the photo rail carriage, and a sensor allowed it to detect that it was in the same spot. An Arduino controls the rail, reads the magnet via a sensor, and controls the camera shutter. The DSLR he’s using can’t do that many frames per second, but that’s a problem for another sci-fi contest.

Holographic-ish displays are finally here, and they’re getting better. But if a display isn’t your speed, perhaps some laser-powered glasses can be the holographic experience you’re looking for?

This project was an entry into the 2022 Sci-Fi Contest. Check out all of the winning entries here.