This Hourglass Flips Itself

Once upon a time, [Mike] bought an hourglass for his sister. He intended to build it into a clock and give it to her as a gift, but life and other projects got in the way. Fast forward a couple of decades to the point when it all came together and [Mike] had everything he needed on hand to build a beautiful wooden clock that automatically flips the hourglass over.

Every 60 minutes, the bulb, which is situated inside a handcrafted maple ring, rotates 180 degrees to restart the flow of sand. Whatever number is at the top of the outer wheel denotes the current hour. The digit for the next hour is always at the five o’clock position relative to the current hour. This works out because the pockets on the outside of the bulb’s ring share a 5:6 ratio with the gear teeth on the outer ring. Confused? Watch the time-lapse video from [Mike]’s that shows it in action.

[Mike] was determined to build this clock using only things he already had on hand, like a cheap digital watch to keep time and a car window motor to rotate the hourglass. He hacked a USB port into the watch so he could use the hourly chime function to trigger the motor through a quad op-amp. The motor runs until it is triggered to shut off optically—a pair of slits cut into the gear that moves the hourglass pass over a sensor. [Mike] built a beautiful box to hold the guts from a nice piece of walnut and spared no detail in the design.

There are a ton of build pictures on the projects site and an in-depth video tour of the clock, which is embedded after the break. Whether they are designed to amaze or confuse, we love a good clock build around here. If you’re into hourglasses, we featured a digital version not too long ago.

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A Lucky Antenna

Antennas come in all shapes and sizes, and which one is best depends wholly on what you are doing with it. A very popular choice for sending video from drones is the cloverleaf antenna. It is circularly polarized which is an advantage when you have a moving vehicle. It also reduces multipath interference.

A cloverleaf contains three closed loops spaced at different angles. The antenna works well for transmitting but isn’t ideal for receiving. It is also difficult to tune after building it. However, for the right job, it is a good performer. [Vitalii Tereshchuk] shows how he made a cloverleaf antenna that fits a WiFi router.

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Paydar: What It Was Like To Battle Bots In 2002

Most people remember when Battle Bots was a big thing, but few of us got to live it as seen in this gallery. Every now and then, someone posts something more amazing than usual in the comments. When [Wolf] was studying at IUPUI they somehow convinced a professor to let them build a scary dangerous robot maiming device for their final project. It’s a cross-disciplinary project — even the medical students may get to participate.

Spike vs hours and hours of work.
Spike vs. hours and hours of work. Victory: spike.

Their bot, unfortunately, got taken out by some spikes after attempting to get a spinbot before it started spinning and got them. If you look closely at the 2002 Comedy Central Battlebot opening you can see the smoke pour from their robot as they try to escape the fatal spikes.

The robot itself is a three wheeled design. The two wheels across from each other drive the robot, and the third steers. There is a very cool encoder mechanism for the steering wheel that is worth checking out. The main drive motor is a hefty 15HP electric forklift motor current limited to 300amps. The robot never got a weapon thanks to slow mechanical engineers, but a motor like that can turn most chunks of metal into deadly weapons.

Battle Bots is making a comeback in some ways. Word’s still out if it will ever go back to it’s prime, or if something more insane will replace it.

Trash Can CNC Gets A Stepper Upgrade

[HomoFaciens] is back at the bench again and working on improvements to his cheap and simple CNC machine.

The video below will no doubt remind you about previous versions of [HomoFaciens]’ CNC builds, which we’ve covered in depth. With an eye to spending as little as possible on his builds, most parts are recovered from e-waste, with a fair amount of Dumpster diving thrown in. For this upgrade, the salvaged brushed DC motors with their signature gap-toothed encoder disks are replaced with genuine bipolar steppers. The primary intention of his build is to learn (and teach) as much as possible, so he spends a good amount of time going over steppers and their control – how to determine phase wiring, how to wire up the not-salvaged-but-still-cheap drivers, directional control, and half-stepping. The mechanics are decidedly dodgy, but there are clever expedients aplenty – we especially like the oil cup fabricated from a brass tube and a bolt with a hole drilled in it. Everything just works, and the results to expense ratio is hard to beat.

While we appreciate the upgrades here, we’re still keen to see how junky his other trash can CNC can get. And we’re still waiting on the paper clip and cardboard challenge.

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An Internet Radio In A Classic Cathedral Case

If you’re looking for a hot collectible item and a great restoration project, cathedral-style radios from the 1930s are a solid choice. But they’re getting harder to find as the years roll by, so if your heart’s content is to listen to modern broadcasts through a radio with a classic look, you may need to roll your own cathedral case for an internet radio.

The cathedral-style case was a hugely successful form-factor for radios back in the day, with variations on the arch-top theme ranging from Gothic to Art Deco. For this build, [nick.r.brewer] decided on a more parabolic arch. His build log has SVG files for the individual ribs that were cut from plywood with an X-Carve. A Raspberry Pi and TFT display were mounted inside the finished case, along with a Bluetooth module and a 20W amplifier and speaker. A big 3-pole rotary switch with custom knob selects the audio source and evokes that 1930s feel. It ended up looking pretty good, and the video after the break shows that it sounds nice, too.

We featured a fair number of internet-radio-in-a-classic-case builds before, but we’re surprised to see no cathedral-style radios have been modded. Maybe it’s time to hit the flea market and estate sales and see what turns up.

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Nessie, The Educational Robot

At the Lifelong Learning Robotics Laboratory at the Erasmo Da Rotterdam in Italy, robots are (not surprisingly) used to teach all of the fundamentals of robotics. [Alessandro Rossetti] and the students at the lab have been at it for years now, and have finally finished their fifth generation of a robot called Nessie. The big idea is to help teach fundamentals of programming and electronics by building something that actually uses these principles.

The robot is largely 3D printed and uses an FPGA to interact with the physical world through a set of motors and sensors. The robot also uses a Raspberry Pi to hold the robot’s framework. The robot manages the sensors in hardware with readers attached to the CPU AXI bus. The CPU reads their values from memory space, though, so the robot is reported to be quite quick.

The lab is hoping to take their robot to a robotics competition in Bari, Italy. We hope that they perform well there, since we are big fans of any robot that’s designed to teach anyone about robotics and programming. After all, there are robots that help teach STEM in Africa, robots that teach teen girls about robots, and robots that teach everyone.

Directional Booklight Invisible To Everyone But You

Consistent contributor [Ken] has cooked up another contraption with his directional booklight. Combining an LED strip and privacy screen filter inside a wooden enclosure, this handy tool is made for someone who wants to read in bed without disturbing anyone else. The booklight sits on top of the page, the LEDs light up just the given area, and because the privacy screen only allows light to come straight off the page, only the reader can see any light and any other viewing angle is obscured.

[Ken] thought of everything. Rather than have the light stay on while the booklight is lifted to turn the page and possibly flash an unsuspecting slumberer, a tactile switch on the underside turns the light on only when it is pressed against the page, allowing very little light to escape.

Future upgrades include another switch on top to detect when the book is closed, and an accelerometer to detect when the reader may have fallen asleep.

We’ve reported a few of [Ken]’s projects before, like his 3D popup cardsunique weather display, and semi-real-life Mario Kart

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