Testing Carbon Fibre Reinforced Filament By Building An Over-Engineered Skateboard

Advances in filaments for FDM 3D printers have come in leaps and bounds over the past few years, and carbon fibre (CF) reinforced filament is becoming a common sight. Robotics extraordinaire [James Bruton] got his hands on some CF reinforced PLA, and ended up building a completely over-engineered 3D printed skateboard. (Video, embedded below.)

[James] started by printing some test pieces with a 0.5 mm and a big 1.2 mm nozzle with and without the CF, which he subjected to cantilever deflection tests. The piece with CF was 20% stiffer than without.

[James] then built an extremely strong and cool looking skateboard deck with alternating section of the CF PLA and toughened PLA, totalling 2.7 kg of filament. It was extremely strong, so after bolting on a set of trucks and wheels, he did some mild riding at a local skate park, where it survived without any problems. He admits it was completely over-engineered, but points out in that the internal cavities in the deck is the perfect place for batteries on an electric long board.

Designing something from the ground up with the strength and weaknesses 3D printing in mind, leads to some very interesting and innovative designs, of which this is a perfect example, and we hope to see many more like it. We’ve featured a number of [James]’ project, including the remote controlled bowling ball he built for [Mark Rober] and his impressive OpenDog and Start Wars robots.

Continue reading “Testing Carbon Fibre Reinforced Filament By Building An Over-Engineered Skateboard”

Quick And Dirty: Operate An Intercom Via Telegram

Never underestimate the quick and dirty hack. It’s very satisfying to rapidly solve a real problem with whatever you have on hand, and helps to keep your hacking skills sharp for those big beautifully engineered projects. [Guillaume M] needed a way to remotely open his apartment building door for deliveries, so he hacked the ancient intercom to be operated via Telegram, to allow packages to be deposited safely inside his mailbox inside the building’s front too.

[Guillaume] needed to complete the hack in a way that would allow him to return the intercom to its original state when he moves out. Opening the 30-year-old unit, he probed a row of screw terminals and identified a 13V supply, ground, and the connection to the buildings’ door lock. He connected the lock terminals to a relay, which is controlled by a Raspberry Pi Zero W that waits for the “open” command to be sent to a custom Telegram Bot.

To power the Pi, [Guillaume] connected it to the 13V supply on the intercom via a voltage divider circuit. Voltage dividers usually make lousy power supplies, since the output voltage will fluctuate as the load changes, but it looks as though it worked well enough for [Guillaume]. The intercom had a lot of empty space inside, so after testing everything was packed inside the housing.

If you want to achieve the same with an ESP8266, there’s a library for that. Just keep in mind that being dependent on web servers to open critical doors might get you locked out.

Cheating At Bowling, The Hacker Way

Anyone who has ever gone to a bowling alley will know the preferred (but ineffective) technique to telepathically control a bowling ball. [Mark Rober] and [James Bruton] decided to change that and hacked a bowling ball that can be steered remotely (and discreetly), simply by leaning your body.

They started with a standard bowling ball, that was cut in half and hollowed out on a lathe. A beam sits on the centre line of the ball, mounted on a bearing in each half to allow the ball to spin around it. Steering done by shifting the centre of mass, by moving a steel pendulum that hangs below the beam side to side with heavy-duty servo. The servo is controlled with an Arduino, and an IMU to detects the balls orientation. Power is provided by and RC Lipo battery. The wireless controller is a sneaky little device that is taped to [Mark]’s back and covered with clothing, and steers the ball by detecting how far he leans with an IMU module. The brain is an Arduino Mini and an NRF24L01 provides the RF link.

While it’s not an easy build, it’s a fairly simple system electronically, with off the shelf electronics modules and perfboard. The genius is in the implementation and its entertainment value. The look on the kids faces when [Mark] “telepathically” controls the ball, after showing off the fact that he has zero natural ability, is absolutely priceless. [Mark Rober], a former NASA engineer, has made a name for himself with viral Youtube videos on cool projects like a glitter booby trap for package thieves and a liquid sand hot tub. [James Bruton], a former toy designer is known for his robotics prowess that he has put on display with OpenDog and functional Star Wars robots.

For us this hack is a perfect example of one that entertains and inspires, a powerful combination for young and old alike. Check out the awesome video after the break. Continue reading “Cheating At Bowling, The Hacker Way”

Electric Longboard Quick Build Using Off-The-Shelf Components.

Building cool things completely from scratch is undeniably satisfying and makes for excellent Hackaday posts, but usually involve a few unexpected speed humps, which often causes projects to be abandoned. If you just want to get something working, using off-the-shelf modules can drastically reduce frustration and increase the odds of the project being completed. This is exactly the approach that [GreatScott!] used to build the 3rd version of his electric longboard, and in the process created an excellent guide on how to design the system and selecting components.

Previous versions of his board were relatively complicated scratch built affairs. V2 even had a strain gauge build into the deck to detect when the rider falls off. This time almost everything, excluding the battery pack, was plug-and-play, or at least solder-and-play. The rear trucks have built in hub motors, the speed controllers are FSESC’s (VESC software compatible) and the remote control system is also an off the shelf system. All the electronics were housed in 3D printed PETG housing, and the battery pack is removable for charging. We just hope the velcro holding on the battery pack doesn’t decide to disengage mid-ride.

The beauty of this video lies in the simplicity and how [GreatScott!] covers the components selection and design calculations in detail. Sometimes we to step back from a project and ask ourselves if reinventing is the wheel is really necessary, or just an excuse to do some yak shaving. Electric long boards are extremely popular at the moment, you can even make a deck from cardboard or make a collapsible version if you’re a frequent flyer.

Jackpot!: The Trials And Tribulations Of Turning A Slot Machine Into An ATM

Have you ever wished that slot machines dispensed money as easily as an ATM? Well so did [Scotty Allen] from Strange Parts, so in collaboration with his friend [Matt] decided to combine the two. After a four-month journey fraught with magic smoke and frustration, they managed to build a fully functional ATM slot machine.

The basic idea is that you insert your card and enter your pin like on a normal ATM, select your winning amount, and pull the lever. This sets wheels spinning, which come to a stop with three-of-a-kind every time, and you win your own money as a bucket load of coins with all the accompanying fanfare. The project took way longer than [Scotty] expected, and he ended up missing his original deadline to show off the machine at DEF CON.

They started with an old broken Japanese slot machine, and replaced the control board with an Arduino Due after a lot of reverse engineering and hacking. [Scotty] did a cool video just on getting the original vacuum fluorescent display working. Integrating the ATM parts proved to be the biggest challenge, with number of very expensive parts releasing their magic smoke or getting bricked in the process. [Scotty] came up with an ingeniously simple hack to interface the ATM hardware with the Arduino. The cash note dispenser uses multiple sensors to detect if there are notes loaded and if one is successfully dispensed. These were spoofed by the Arduino, which controls two coin hoppers instead to dispense appropriate amount of quarters or pennies. The build was rounded off with some very neat custom graphics on the glass panels, and the machine was finally showed off at a local arcade.

This was an awesome project, and we can appreciate the fact that [Scotty] made no attempt to hide the real emotional roller coaster that anyone who has worked on a large project knows, but is rarely documented in logs. [Scotty] has made a name for himself by building his own iPhone from parts and touring Shenzhen’s many factories. Check out the videos after the break Continue reading “Jackpot!: The Trials And Tribulations Of Turning A Slot Machine Into An ATM”

Needling Your Projects: 3D Printed PCB Probing Jig Uses Accupuncture Needles

Trying to probe a modern electronic circuit with tiny SMD components, without letting the magic smoke escape in the process, can be quite a challenge. Especially since we hackers have not yet developed the number of appendages required to hold 3 different probes in place while operating both an oscilloscope and a computer. [Giuseppe Finizia] solved this problem with a 3D printed PCB probing jig that uses acupuncture needles.

As part of [Giuseppe] day job as an engineer at an electronic forensics laboratory, he does technical investigations on seized devices, which involves quite a bit of probing. The jig consists of a base plate with slots in which PCB holders of various configurations slide to hold all shapes and sizes of PCBs. Around the circumference of the plate there are multiple positions for adjustable probing “cranes”, each of which hold an acupuncture needle that is crimped or soldered to a wire. Each needle holder has a bit of flex which allows it to maintain downward pressure for a positive connection.

Making one-off tools and jigs is arguably one of the best applications for 3D printing, of which this is a perfect example. You can of course point solder wires or use test hooks if you have something to grab onto, but for easily probing multiple point on any PCB, this looks like a damn good solution. If you’re trying to trace a single signal, a precision pantograph might be your friend, or you can add a foot switch to your oscilloscope for quickly checking a circuit by hand.

[Jonathon Oxer] from the YouTube channel SuperHouse did a very nice video on the jig and made some small modifications. Check out the video after the break.

DIY Electrolysis Tank: Removing Rust While You Sleep

Anyone who’s done a bit of metalworking will know how quickly your stockpile will pick up a coating of rust with even just a bit of humidity. While welding requires only a bit of wire brushing at the joint areas, cleaning a large frame for paint is a completely different story. The projects [Make it Extreme] gets himself into tend to involve a lot of steel, so he built his own electrolysis tank for rust removal.

Electrolytic rust removal involves placing the piece of steel to be cleaned into an alkaline electrolyte solution (water and washing soda) with a sacrificial steel anode and connecting a low voltage DC supply over the two pieces. [Make it Extreme] started with an old plastic container, around which he built a very neat trolley frame. He obviously put some thought into how the tank will be cleaned, since it can be removed by unscrewing six bolts and removing the top part of the frame.

The high current, low voltage power supply that is required for the process was built using an old microwave transformer. The secondary coil is removed and replaced with coil of thick insulated wire, to convert it into a step down transformer. After the rewinding the transformer outputs about 13 VAC, which is then run through beefy bridge rectifier modules to get a DC current. A custom machined copper bolt terminal is mounted through the side of the tank to attach the sacrificial anode plate to the positive lead of the power supply, while the negative lead is clamped to the rusty steel to be cleaned.

[Make it Extreme]’s projects never get old, with everything from rideable tank tracks to rotary electric guns. Check out the video after the break to see the build and an impressive demo. Continue reading “DIY Electrolysis Tank: Removing Rust While You Sleep”