Hackaday Podcast Episode 286: Showing Off SAOs, Hiding From HOAs, And Beautiful Byproducts

August 30, 2024 by Dan Maloney 2 Comments

Even when the boss is away, the show must go on, so Dan slid back behind the guest mic and teamed up with Tom to hunt down the freshest of this week’s hacks. It was a bit of a chore, with a couple of computer crashes and some side-quests down a few weird rabbit holes, but we managed to get things together in the end.

Tune in and you’ll hear us bemoan HOAs and celebrate one ham’s endless battle to outwit them, no matter what the golf cart people say about his antennas. Are you ready to say goodbye to the magnetic stripe on your credit card? We sure are, but we’re not holding our breath yet. Would you 3D print a 55-gallon drum? Probably not, but you almost can with a unique Cartesian-polar hybrid printer. And, if you think running MS-DOS on a modern laptop is hard, guess again — or, maybe you just have to get really lucky.

We also took a look at a digital watch with a beautiful display, a hacked multimeter, modern wardriving tools, switchable magnets, and debate the eternal question of v-slot wheels versus linear bearings. And finally, you won’t want to miss our look at what’s new with 3D scanning, and the first installment of Kristina’s new “Boss Byproducts” series, which delves into the beauty of Fordite.

Download the DRM-free MP3.

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A Little Optical Magic Makes This Floating Display Pop

August 29, 2024 by Dan Maloney 4 Comments

If there’s a reason that fancy holographic displays that respond to gestures are a science fiction staple, it’s probably because our current display technology is terrible. Oh sure, Retina displays and big curved gaming monitors are things of wonder, but they’re also things that occupy space even when they’re off — hence the yearning for a display that can appear and disappear at need.

Now, we’re not sure if [Maker Mac70]’s floating display is the answer to your sci-fi dreams, but it’s still pretty cool. And, as with the best of tricks, it’s all done with mirrors. The idea is to use a combination of a partially reflective mirror, a sheet of retroreflective material, and a bright LCD panel. These are set up in an equilateral triangle arrangement, with the partially reflective mirror at the top. Part of the light from the LCD bounces off the bottom surface of the mirror onto a retroreflector — [Mac] used a sheet of material similar to what’s used on traffic signs. True to its name, the retroreflector bounces the light directly back at the semi-transparent mirror, passing through it to focus on a point in space above the whole contraption. To make the display interactive, [Mac] used a trio of cheap time-of-flight (TOF) sensors to watch for fingers poking into the space into which the display is projected. It seemed to work well enough after some tweaking; you can check it out in the video below, which also has some great tips on greebling, if that’s your thing.

We suspect that the thumbnail for the video is a composite, but that’s understandable since the conditions for viewing such a display have to be just right in terms of ambient light level and the viewer’s position relative to the display. [Mac] even mentions the narrow acceptance angle of the display, touting it as a potential benefit for use cases where privacy is a concern. In any case, it’s very different from his last sci-fi-inspired volumetric display, which was pretty cool too.

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A mini Cyclone game consisting of an Arduino, an LED ring, and button, plus a scoreboard on a 16x2 LCD.

2024 Tiny Games Contest: Mini Cyclone Tests Reaction Time

August 29, 2024 by Kristina Panos 3 Comments

Round and round goes the red LED, and if you can push the button when it overlaps the green LED, then you win. Cyclone is almost too simple of a game, and that’s probably part of why it’s so addictive.

Want to make one for your desk? All it takes is an Arduino Nano R3 or comparable microcontroller, an RGB LED ring with 12 LEDs, a 16×2 LCD, a buzzer, and a momentary push button switch.

Interestingly, there aren’t successive levels with increasing speed, but each round begins with a randomized speed value. Of course, this can all be easily changed in the code, which is modified from [Joern Weise]’s original.

This is a tinier version of [mircemk]’s original project, which uses a 60-LED ring and does contain levels. As usual with [mircemk]’s builds, this project is mounted on their trademark 3 mm PVC board and covered with peel-and-stick wallpaper. Be sure to check out the demo and build video after the break.

Don’t forget! You have until Tuesday, September 10th to enter the 2024 Tiny Games Contest, so get crackin’!

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A tricked-out kids' Jeep in black and silver.

Driven To Over-Engineer A Kids’ Car

August 29, 2024 by Kristina Panos 12 Comments

You know, it feels as though it’s getting more and more difficult to compete for Father of the Year around here. And [Jon Petter Skagmo] just laid down a new gauntlet — the incredibly overly-engineered kids car.

While the original plan was to build the entire car from scratch, [Jon] eventually opted to use an off-the-shelf car that had a dead battery.

While the original architecture was quite simple, the new hardware has just about everything a kid could want in a tricked-out ride, most of which is accessible through the really cool dashboard.

We’re talking headlights, a music player, a siren, a selfie video cam that doubles as two-way communication with the driver, and even a garage door opener that uses an MQTT connection.

Under the cute little hood is where you’ll find most of the electronics. The car’s brain is a Raspberry Pi 3B, and there’s a custom daughter board that includes GPS/GNSS. This was originally meant to geofence [Baby Girl Skagmo] in, but Dad quickly realized that kids are gonna kid and disabled it pretty soon after.

This isn’t the first high-tech rebuild of a kiddie car that we’ve seen here at Hackaday. Makes us wish we were quite a bit smaller…

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The blind maze -- a box with three buttons and three light-up panels that indicate walls.

2024 Tiny Games Contest: Blind Maze Is Fun For All

August 29, 2024 by Kristina Panos 5 Comments

If you think about it, even difficult mazes on paper are pretty easy. You can see all the places you can and can’t go, and if you use a pencil instead of a pen, well, that’s almost like cheating.

However, using a pencil is pretty much a necessity to play [penumbriel]’s Blind Maze. In this game, you can’t even see the maze, or where you are. Well, that’s not exactly true — you can “touch” the wall (or lack thereof) in front of you and to the sides, but that’s it. So you’re going to need that pencil to draw out a map as you go along.

This game runs on an Arduino Nano and a 18650 cell. There are three LEDs deep within the enclosure, which is meant to give the depth of walls. But, even the vision-impaired can play the Blind Maze, because there’s haptic feedback thanks to a small vibration motor.

If you want to play in hard mode, there’s a hidden paperclip-accessible switch that turns off the LEDs. This way, you have to rely on hitting the walls with your head. Be sure to check out the video below.

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Reconfigurable Tracked Robot Has Some Neat Flexible Abilities

August 29, 2024 by Lewin Day 9 Comments

When you think of tracked robots, you might think of bomb disposal robots or others used in military applications. You probably haven’t seen anything quite like this, however—it’s a “reconfigurable continuous track robot” from researchers [Tal Kislasi] and [David Zarrouk (via IEEE Spectrum).

The robot looks simple, like some kind of tracked worm. As its motors turn, the track moves along as you would expect, propelling the robot along the ground. Its special feature, though, is that the track can bend itself up and down, just like a snake might as it rises up to survey a given area.

The little tracked robot can thus tilt itself up to climb steps, and even bend itself over small obstacles. It can even try and hold itself up high as it inches along to try and bridge its way over a gap.

The robot can selectively lock each link (or not) as it passes by.

How does it achieve this? Well, the robot is able to selectively lock the individual links of its outer track in various orientations. As the links pass over the front of the robot, a small actuator is used to lock each link in a 20-degree orientation, or a straight orientation, or leave them loose.

The ability to lock multiple links into a continuous rigid structure allows the robot to rise up from the ground, form itself into a stiff beam, or conform to the ground as desired. A mechanism at the back of the robot unlatches the links as they pass by so the robot retains flexibility as it moves along.

It’s a nifty design, and one we’d like to see implemented on a more advanced tracked robot. We’ve explained the benefits of tracked drivetrains before, too.

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Adding Human Detection To Home Automation

August 29, 2024 by Bryan Cockfield 38 Comments

Radar made a huge impact when it was first invented, allowing objects to be detected using radio waves which would normally be difficult or impossible to observe through other means. Radio waves of all frequencies can be used for radar as well, whether that’s detecting ships beyond the horizon, tracking aircraft near an airport, penetrating the ground, or imaging objects with a high resolution. At the millimeter wavelength it’s fairly easy to detect humans with the right hardware, and using some inexpensive radar modules [Tech Dregs] shows us how to add this capability a home automation system.

Since these modules aren’t trying to image humans with fine detail or detect them at long range, the hardware can be fairly inexpensive. [Tech Dregs] is using the LD2410B modules which have not only an on-board microcontroller but also have the radio antennas used for radar built right onto the PCB. They have a simple binary output which can communicate whether or not a human is detected, but there’s also UART for communicating more details about what the module senses in the room. [Tech Dregs] is using this mode to connect the modules to Home Assistant, where they will be used to help automate his home’s lighting.

The only significant problem he had setting these modules up was getting them built into an enclosure. The short wavelengths used in this type of radar module don’t penetrate solid objects very well at all, so after trying to hide one behind an e-ink screen he eventually settled on hollowing out a space in a bezel with very thin plastic between the module and the room. If you need more out of your radar modules than object detection, though, you can always try building a pulse compression radar which can provide much more accurate ranging of objects.

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