Low Buck PVC ROV IS Definitely A MVP

December 2, 2021 by Ryan Flowers 8 Comments

Do you have a hundred bucks and some time to kill? [Peter Sripol] invites you to come along with him and build a remotely operated submarine with only the most basic, easily accessible parts, as you can see in the video below the break.

Using nothing more than PVC pipe, an Ethernet cable, and a very basic electrical system, [Peter] has built a real MVP of a submarine. No, not Most Valuable Player; Minimum Viable Product. You see, there’s not a microcontroller, motor controller, sensor, or MOSFET to be found except for that which might reside inside the knock-off GoPro style camera which is encased in a candle wax sealed enclosure.

Instead, simple brushed motors live right out in the open water. Single pole double throw switches are connected to 100 feet of Ethernet cable and control the relays powering the motors. The camera signal is brought back to the controller through the same cable. Simple is the key to the build, and we have to admit that for all of its Minimum Viability, the little ROV has a lot going for it. [Peter] even manages to use the little craft to find and make possible the retrieval of a crustacean encrusted shopping cart from a saltwater canal. Not bad, little rover, not bad.

Also noteworthy is that the video below has its own PVC ROV Sea Shanty, which is something you just don’t hear every day.

Underwater ROV builds are the sort of thing almost every hacker thinks about doing at least once, and some hackers even include Lego, magnets, and balloons in their builds! Continue reading “Low Buck PVC ROV IS Definitely A MVP” →

Giving Flip Dots The Oil Treatment To Shut Them Up

November 30, 2021 by Mike Szczys 20 Comments

Flip dot displays are awesome — too bad it’s so hard to find large panels to play around with, but that’s for another article. [Pierre Muth] has been working to find different and interesting things to do with these flip dots, and he recently explored how you can flip them very very gently.

Now you likely remember [Pierre’s] work from earlier this year where he was pushing the speed of the displays as high as possible. Using a capacitor discharge trick he made it to 30 fps, which absolutely stunning work. This time around he attempted to do something equally impressive by micro-stepping the dots. It’s a bonkers idea and unfortunately didn’t work. It seems the dots are engineered for two steady states and you just can’t get very good performance with the in-between states.

However, along the way he had an a-ha moment. Part of what he wanted to do with the microstepping was to slow down the change of the state and for that, he just grabbed a viscous fluid that’s thicker than air: Vaseline oil. (We’d imagine it’s not the cocoa-scented variety, but who knows?) He’s taken a page out of the mineral-oil-cooled PC sub-genre and applied it to flipdots. But watch the video after the break and you’ll see that the slower animations are super pleasing to watch, and the clickity-clackity that was driving you nuts while trying to works is now whisper quiet. It’s a new dawn for displays.

Continue reading “Giving Flip Dots The Oil Treatment To Shut Them Up” →

Z80 Video Output Via The Raspberry Pi Pico

November 28, 2021 by Lewin Day 27 Comments

Building basic computers from the ground up is a popular pastime in the hacker community. [Kevin] is one such enthusiast, and decided to whip up a video interface for his retro Z80 machine.

The computer in question is a RC2014 Classic ][, a popular single-board 8-bit computer kit. As standard, it doesn’t have a video output, so [Kevin] built one using the PIO interface of the Raspberry Pi Pico.

74-series logic is pressed into service to handle address selection, enabling the Pico and Z80 to effectively communicate. Wait states in the Z80 are used to avoid the vintage chip tripping over when the two are communicating. The Pico outputs video in 160 x 120 resolution with eight bits of color per pixel, using a simple resistor-ladder DAC to do basic VGA.

The build serves as a great way to get familiar with programming both the Pi Pico and the Z80 itself. With that said, it’s probably possible to simply just emulate the Z80 on the Pi Pico given the latter runs at a default clock rate of 125 MHz, eclipsing the RC2014’s snail-like 7.3728 MHz main clock.

If you’ve been building your own retro graphics hardware, do let us know. We love that sort of thing around here!

A man using a homemade vacuum apparatus to climb a wall

Scale Buildings With The Power Of Suction

November 28, 2021 by Chris Wilkinson 30 Comments

Walls can’t hold [Elijah Cirioli]. The would-be superhero has been busy scaling the sides of buildings using his self-contained vacuum climbers. (Video embedded after the break.)

After being inspired by the winning project of an Air Force design challenge, our plain-clothed crusader got to work on a pair of prototype vacuum climbers. The wooden prototypes were an unexpected success, so work soon began on the models featured in the video after the break. The main improvements in this second version included using ¼ inch acrylic instead of plywood, as well as an improved gasket for a better seal against the imperfect exterior of many building walls.

While the system would still ultimately struggle with brick walls (and other imperfect surfaces), it performs more than adequately when ascending smoother concrete walls. And while the acrylic was a far better choice than the plywood, one of the acrylic panels still developed a fracture. Even so, the results speak for themselves, and we have to applaud the inventor’s seemingly unconditional trust in his equipment.

We haven’t seen a follow-up from [Elijah Cirioli] recently, so here’s hoping that he’s busy working on version three, and that he’s not stuck up a wall somewhere. In the meantime, check out how someone accomplished similar wall-climbing feats using salvaged microwave transformers.

Continue reading “Scale Buildings With The Power Of Suction” →

Magnus Effect Propels This Flettner Rotor Boat

November 27, 2021 by Lewin Day 13 Comments

The Magnus effect is a interesting and useful phenomena. [James Whomsley] from [Project Air] decided to put it to work on a small radio-controlled boat, successfully harnessing the effect. (Video, embedded after the break.)

The Magnus effect is an interesting thing, where fluid flowing over a rotating object generates an aerodynamic force at a right angle to the direction of the flow and the axis of rotation. (It’s why curveballs curve.) This can be used for propulsion on a boat, by spinning a tall cylinder called a Flettner rotor. This takes advantage of Magnus effect to generate thrust.

The boat uses a 3D-printed hull, sealed up with a leak sealer spray and lots of spray paint to avoid leaks. In the center of the catamaran design, there’s a spinning rotor belt-driven by a brushless motor. Outside of the rotor for thrust, a simple rudder is used for steering.

With the rotor turning, the boat was able to successfully sail along with the benefit of the thrust generated from the wind. However, there were teething issues, with heavy winds quickly capsizing the boat. [James] realized that adding some proper keels would help avoid the boat tipping over.

We’ve seen [James] around these parts before, namely with the Magnus-effect aircraft that preceded this build.

Continue reading “Magnus Effect Propels This Flettner Rotor Boat” →

Cracking Open The Prince Floppy After The Purple Reign

November 23, 2021 by Kristina Panos 21 Comments

Readers of a certain vintage will no doubt remember the time when Prince eschewed his royal position and became an unpronounceable symbol. People had no choice but to refer to him as TAFKAP, The Artist Formerly Known As Prince, and members of the music press were sent a 3.5″ floppy disk with a font file containing a single character — that gender-transcending shape that would soon become another one of Prince’s guitars. But it’s 2021, and now you can get it from the Internet Archive. Fun fact: the file wasn’t ever locked down. In fact, the symbol was available on Prince’s Compuserve and fan club CD-ROM.

While some people trawl auction sites for overalls and weird keyboards, others look for ridiculous items from the zeitgeist, like a copy of this floppy. Take [Anil Dash] for instance. [Anil] finally pulled the trigger after 15 years of debating this particular purchase. [Anil]’s interest was reignited after reading this analysis of whether the symbol could ever be put into Unicode. (Between being trademarked, a logo, and a personal character, it’s ineligible for inclusion.)

Earlier this week, [Anil] teamed up with Adafruit to extract the data from the floppy. The Twitter thread that ensued led readers to another old source of the font — the 1994 game Prince Interactive. We wonder if they broke out the oscilloscope, though it doesn’t look like it.

Thanks for the tip, [pt and limor]!

Cheating A Pedometer The Easy Way

November 20, 2021 by Lewin Day 9 Comments

These days, pedometers are integrated into just about every smartwatch on the market, and some of the dumber ones too. Tracking step counts has become a global pastime, and at times, a competitive one. However, any such competition can easily be gamed, as demonstrated by [Luc Volders].

Generally, all it takes to fool a basic pedometer is a gentle rhythmic jiggling motion of some sort. Cheaper devices will even register steps with little more than vague shaking.

[Luc] exploited this with basic machinery. A servo’s output shaft is fitted with a 3D printed cylinder, sized to allow a smartwatch to be attached as if to a wrist. Then, a Raspberry Pi Pico simply rocks the servo back and forth at regular intervals, and the watch begins counting these ersatz steps. Looking at the project as a whole, we’re betting [Luc] took some inspiration from old-fashioned automatic watch winders.

It’s hard to envision an important application for this technology. However, if one is in a friendly competition with friends who don’t scrutinize the results too closely, this would be an easy way to win.

Alternatively, consider building a pedometer to track your hamster’s exercise regime. If you’ve got your own exercise hacks on the go, drop us a line!