DIYing A High End Camera Arm

September 27, 2020 by Lewin Day 21 Comments

One of the first purchases for anyone looking to shoot video should be a tripod. Key to getting clean and stable shots, they can nevertheless be limiting in their range of motion. Wanting something a little more high-end, but dissatisfied with the high cost of commercial options, [Alexandre Chappel] decided to build his own camera arm.

The build is based around square alumiunium tubing, with the high-tolerance material acting as the arm’s vertical and horizontal rails. 3D printed brackets and adapters are used to bolt everything together, along with several printed components used as drilling guides to help accurately machine the aluminium tubes. Adjustment is built into the carriages that travel along the rails, to help account for any slop in the 3D printed parts. A counterweight system is then installed to ensure the camera doesn’t hit the floor when not in the locked position.

It’s a tidy build, and one that has given [Alexandre] far more flexibility to shoot than his existing tripods. Additionally, adjusting the camera position is much quicker than before. Of course, when you’re building your own rigs, the sky is the limit. Video after the break.

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Rocket Plane Build Aims For High Speed Flight

September 27, 2020 by Lewin Day 19 Comments

[James Whomsley] likes flying, and likes flying fast. After reaching a speed of 114 miles an hour with an RC plane, he wanted to go further and break that record. To do so, he looked towards rocket power, and started a new build.

The design consists of a combination of 3D printed parts, laser-cut plywood bulkheads, and foamboard flight surfaces, with a few carbon fiber stiffeners thrown in here and there. For this early prototype, power is solely from hobby rocket motors, providing thrust for 1.6 seconds, meaning flight times are necessarily short. The craft is launched from an aluminium profile rail thanks to a 3D printed sliding guide pin.

Initial tests with two rocket motors were promising, leading to a second trial with a full six motors fitted. The thrust line was a little low, however, and a major pitch-up just after launch meant the plane only reached around 62 miles an hour. [James] still has a ways to go to beat his previous record, so intends to explore adding ducted fan propulsion to get the plane in the air before using the rockets as a speed booster in steady flight.

Of course, if you can’t lay your hands on rocket engines, you could always consider spinning up your own. (Or ditch the engine entirely.) Video after the break.

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Tesla Turbine Boat Uses Lily Impeller

September 26, 2020 by Lewin Day 19 Comments

Typically in the RC community, radio control boats rely on small nitro engines or electric motors to get around. Fitted with traditional propellers, they’re capable of great speed and performance. Of course, there’s more than one way to skin a cat, as [Integza] shows with his latest build.

As far as the boat side of things is concerned, it’s a basic 3D printed single hull design. The innovation comes in the drivetrain, instead. The boat uses compressed air for propulsion, stored in a battery of four soda bottles, pressurized to 6 bar. The compressed air is used to drive a Tesla turbine of [Integza]’s design, which is 3D printed on a resin printer. Rather then driving a propeller, the Tesla turbine instead turns a Lily impeller, which pulls the boat through the water rather than pushing it along. The impeller uses a nature-inspired design, hence the name, and was also 3D printed, making producing its complex geometry a cinch. The guts of a toy radio control car are then used to control the boat.

Understandably, performance is less than stellar. The limited reserves of compressed air can’t propel the boat long, and the combination of the high RPM Tesla turbine and Lily impeller don’t provide a lot of thrust. However, the boat does move under its own power, demonstrating these oddball technologies while doing so.

[Integza] has been working with these technologies for a while; we featured an earlier Tesla turbine build back in 2018. Video after the break.

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A Digital Guestbook Is A Perfect Hacker Wedding Gift

September 22, 2020 by Lewin Day 2 Comments

With his brother’s wedding coming up, [Sebastian] needed a wedding gift. Rather than purchasing something, he elected to build a digital guestbook so guests could share their well-wishes with the happy couple.

The guestbook has a simple web-based interface, which was accessible over a domain name [Sebastian] registered with the couple’s names ahead of the event. There, users could enter text and draw a friendly message for the digital guestbook. The guestbook itself consists of an ESP32 running a e-ink display, packaged in a tidy 3D printed enclosure featuring the couple’s initials. It regularly queries the web server, and displays the messages it finds on the screen.

It’s a great use of an e-ink display, as it made reading the messages in bright daylight easy where other technologies may have faltered. [Sebastian] was also clever to install some LEDs for the night portion of the reception. We’ve featured a few wedding gifts on these pages before, including this particularly amusing sugar cube. Video after the break.

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Building A Cell Testing Station For 18650s

September 21, 2020 by Lewin Day 34 Comments

The 18650 is perhaps the world’s favorite lithium battery, even if electric car manufacturers are beginning to move towards larger cells such as the 21700. Used heavily in laptops and flashlights, it packs a useful amount of energy into a compact, easy to use package. There’s a small industry that has developed around harvesting these cells from old equipment and repurposing them, and [MakerMan] wanted to a piece of the action. Thus, he created a cell testing station to help in the effort.

Make no mistake, this is not a grandiose smart cell tester with 40 slots that logs every last iota of data into a cloud spreadsheet for further analysis. Nope, this is good old fashioned batch processing. [MakerMan] designed a single PCB that replicates the same cell testing circuit four times. Since PCB houses generally have a minimum order quantity of ten units, [MakerMan] ended up with forty individual cell testers on ten PCBs. Once populated, the boards were installed on a wooden frame with an ATX power supply which supplies the juice to run the system.

Overall, it’s a quick, cheap way for capacity testing cells en masse that should serve [MakerMan] well. We look forward to seeing where these cells end up. We’ve seen his work before, too – with a self-built laser engraver a particular highlight. Video after the break.

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Custom Strain Gauges Help Keep Paraglider Aloft

September 20, 2020 by Dan Maloney 13 Comments

No matter what they’re flying, good pilots have a “feel” for their aircraft. They know instantly when something is wrong, whether by hearing a strange sound or a feeling a telltale vibration. Developing this sixth sense is sometimes critical to the goal of keeping the number of takeoff equal to the number of landings.

The same thing goes for non-traditional aircraft, like paragliders, where the penalty for failure is just as high. Staying out of trouble aloft is the idea behind this paraglider line tension monitor designed by pilot [Andre Bandarra]. Paragliders, along with their powered cousins paramotors, look somewhat like parachutes but are actually best described as an inflatable wing. The wing maintains its shape by being pressurized by air coming through openings in the leading edge. If the pilot doesn’t maintain the correct angle of attack, the wing can depressurize and collapse, with sometimes dire results.

Luckily, most pilots eventually develop a feel for collapse, sensed through changes in the tension of the lines connecting the wing to his or her harness. [Andre]’s “Tensy” — with the obligatory “McTenseface” surname — that’s featured in the video below uses an array of strain gauges to watch to the telltale release of tension in the lines for the leading edge of the wing, sounding an audible alarm. As a bonus, Tensy captures line tension data from across the wing, which can be used to monitor the performance of both the aircraft and the pilot.

There are a lot of great design elements here, but for our money, we found the lightweight homebrew strain gauges to be the real gem of this design. This isn’t the first time [Andre] has flown onto these pages, either — his giant RC paraglider was a big hit back in January.

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Finally, A Differently Useless Machine

September 20, 2020 by Kristina Panos 32 Comments

Traditionally, the useless machine is a simple one that invites passersby to switch it on. When they do, the machine somehow, some way, turns itself off; usually with a finger or finger-like object that comes out from the box in what feels like an annoyed fashion. Honestly, that’s probably part of what drives people to turn them on over and over again.

But [Bart Blankendaal] has managed to turn the useless machine on its head. When this machine is switched to the on position, unseen forces inside the box will spin the toggle switch around 180° to the off position.

What’s really happening is that an Arduino is getting a signal from the toggle switch, and is then rotating it on a ball bearing with a stepper motor driven through an H-bridge.

It shouldn’t be too hard to make one of these yourself, given that [Bart] has provided the schematic and STLs. If we weren’t living in such touchy times, we might suggest building one of these into your Halloween candy distribution scheme somehow. Sell the switch as one that turns on a candy dispenser, and then actually dispense it after three or five tries.

Many see useless machines as tangible examples of existential quandary. Here is one that takes that sentiment a bit further by snuffing out a candle.

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