Leg Mounted Beer Bottles for Underwater Propulsion

Sitting on the beach, finishing off a beer one day, [Rulof] realized that if he put a motor in the beer bottle with a propeller at the bottle’s mouth, he could attach the result to his leg and use it to propel himself through the water. Even without the added bonus of the beautiful Mediterranean waters through which he propels himself, this is one hack we all wish we’d thought of.

These particular beer bottles were aluminum, making cutting them open to put the motor inside easy to do using his angle grinder. And [Rulof] made good use of that grinder because not only did he use it to round out parts of the motor mounting bracket and to cut a piston housing, he also used the grinder to cut up some old sneakers on which he mounted the bottles.

You might wonder where the pistons come into play. He didn’t actually use the whole pistons but just a part of their housing and the shaft that extends out of them. That’s because where the shaft emerges from the housing has a water tight seal. And as you can see from the video below, the seal works well in the shallow waters in which he swims.

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Contender For World’s Most Unsettling Drone?

We’re not sure what FESTO is advertising with their odd flying beach ball. Amongst inspirational music it gently places its translucent appendage over a water bottle and then engulfs it with an unsettling plastic sound. With a high pitched whine it hovers away with its prey and deposits it in the hand of a thirsty business man, perhaps as a misguided nurturing instinct.

Despite discovering a new uncanny valley, the robot is pretty cool. It appears to a be a hybrid airship/helicopter on a small-scale. The balloon either zeros out the weight of the robot or provides slightly more lift. It’s up to the propellers to provide the rest.

We like the carbon fiber truss around the drone. It’s a really slick build with barely an untamed wire. This seems like a much safer design than a quadcopter for indoor flying. If its end effector wasn’t so creepy it would be even cooler. Video after the break.

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Automating RC Motor Efficiency Testing

Small brushless motors and LiPo batteries are one of the most impressive bits of technology popularized in recent years. Just a few years ago, RC aircraft were powered by either anemic brushed motors or gas. Quadcopters were rare. Now, with brushless motors, flying has never been easier, building electric longboards is simple, and electric bicycles are common.

Of course, if you’re going to make anything fly with a brushless motor, you’ll probably want to know the efficiency of your motor and prop setup. That’s the idea behind [Michal]’s Automated RC Motor Efficiency Tester, his entry to the 2016 Hackaday Prize.

[Michal]’s project is not a dynamometer, the device you should use if you’re measuring the torque or power of a motor. That’s not really what you want if you’re testing brushless motors and prop configurations, anyway; similarly sized props can have very different thrust profiles. Instead of building a dyno for a brushless motor, [Michal] is simply testing the thrust of a motor and prop combination.

The device is very similar to a device sold at Hobby King, and includes a motor mount, microcontroller and display, and a force sensor to graph the thrust generated by a motor and prop. Data can be saved to an SD card, and the device can be connected to a computer for automatic generation of pretty graphs.

Brushless motors are finding a lot of uses in everything from RC planes and quadcopters, to robotics and personal transportation devices. You usually don’t get much of a data sheet with these motors, so any device that can test these motors will be very useful.

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3D Printed Quadcopter Props

Here’s something that isn’t quite a hack; he’s just using a 3D printer as a 3D printer. It is extremely interesting, though. Over on Hackaday.io [Anton] is creating 3D printable propellers for quadcopters and RC planes. Conventional wisdom says that propellers require exceedingly exacting tolerances, but [Anton] is making it work with the right 3D file and some creative post-processing treatment of his prints.

These 3D printed props are a remix of an earlier project on Thingiverse. In [Anton]’s testing, he didn’t get the expected lift from these original props, so a few small modifications were required. The props fit on his 3D printer bed along their long edge allowing for ease of slicing and removal of support material. For post-processing, [Anton] is using acetone vapor smoothing on his ABS printed design. They come out with a nice glossy sheen, and should be reasonably more aerodynamic than a prop with visible layer lines.

Although [Anton]’s prop is basically a replica of a normal, off-the-shelf quadcopter prop, 3D printing unique, custom props does open up a lot of room for innovation. The most efficient propeller you’ll ever find is actually a single-bladed propeller, and with a lot of experimentation, it’s possible anyone with a well-designed 3D printer could make turn out their own single-blade prop.

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The Open, Hackable Electronic Conference Badge

Electronic conference badges have been around for at least a decade now, and they all have the same faults. They’re really only meant to be used for a few days, conference organizers and attendees expect the badge to be cheap, and because of the nature of a conference badge, the code just works, and documentation is sparse.  Surely there’s a better way.

Enter the Hackable Electronic Badge. Ever since Parallax started building electronic conference badges for DEF CON, they’ve gotten a lot of requests to build badges for other conventions. Producing tens of thousands of badges makes Parallax the go-to people for your conference badge needs, but the requests for badges are always constrained by schedules that are too short, price expectations that are too low, and volumes that are unknown.

There’s a market out there for electronic conference badges, and this is Parallax’s solution to a recurring problem. They’re building a badge for all conferences, and a platform that can be (relatively) easily modified while still retaining all its core functionality.

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Hacklet 73 – Parallax Propeller Projects

In 2006, Parallax, Inc wasn’t new to the electronics business. They’d been around since 1987. Still, for a relatively small company, jumping into custom chips is a big leap. Parallax didn’t just jump into some cookie cutter ASIC, they made their own parallel multi-core microcontroller. Designed by [Chip Gracey], the Parallax Propeller has 8 cores, called cogs. Cogs are connected to I/O pins and other resources by a hub. The Propeller saw commercial success, and continues to have a loyal following. This week’s Hacklet is about some of the best Propeller projects on Hackaday.io!

wozWe start with retrocomputing prop star [Jac Goudsmit] and L-Star: Minimal Propeller/6502 Computer. [Jac] loves the classic 6502 processor. Inspired by [Ben Heckendorn’s] recent Apple I build, [Jac] wanted to see if he could replicate an Apple I with minimal parts. He built upon the success of his Software-Defined 6502 Computer project and created L-Star. The whole thing fits on a Propeller proto board with room to spare. The project uses a 6502, with a Propeller handling just about everything else. The system takes input from a PS-2 keyboard, and outputs via composite video, just like the original Apple I. As you can see from the photo, it’s quite capable of displaying Woz in ASCII. [Jac] has expanded the L-Star to support the Ohio Scientific C1P and CompuKit UK101, both early 6502 based computers.


bbotNext up is [Mike H] with B-BOT. B-BOT is a balancing robot. [Mike] used B-BOT to learn about designing with the Propeller and programming in SPIN, the Prop’s built-in interpreted language. While slower than assembler, SPIN was plenty fast enough to solve the classic inverted pendulum problem. B-BOT’s primary sensor is a Pololu AltIMU-10. This module contains a gyro, accelerometer, compass, and altimeter all on one tiny board. Locomotion comes in the form of two stepper motors. Command and control is via X-Bee radio modules. All the parts live on a custom PCB [Mike] milled using his CNC router.


xynq[Antti.lukats] created Soft Propeller, his entry in the 2015 Hackaday Prize. Soft Propeller doesn’t use a hardware Propeller at all. The core of the system is a Xilinx Zynq-7 chip, which contains an FPGA and a Dual Core ARM A9+ processor. Back in 2014, Parallax released the Verilog HDL code for the Propeller core. [Antti] has taken this code and ported it over the Zynq-7. With 256Kb of RAM, 16 MB of Flash and an LED, the entire system fits in a DIP package smaller than a stick of gum.


pipmanFinally, we have [Christian] with Pipman GPS Watch. There’s just something about the Pip-boy from the Fallout video game series. This Personal Information Processor (PIP) has spawned hundreds of projects from cosplayers and electronics hobbyists alike. [Christian’s] version uses a 4D systems TFT LCD to display those awesome graphics. Input comes through a 5 way navigation switch. A GPS and compass module provide all the navigation data Pipman needs. At the center of it all is a Parallax Propeller programmed in SPIN. [Christian] has a working prototype on his bench. He’s now working on modeling a 3D printed case with Blender.

There are a ton of Propeller projects on Hackaday.io. If you want to see more, check out our Propeller Project list! Did I miss your project? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Hackaday Prize Entry: An FPGA’d Propeller

The Parallax Propeller is an exceptionally interesting chip that doesn’t get the love it deserves. It’s a 32-bit microcontroller with eight independent cores that are each powerful enough to do some real computation.  Around this time last year, the source for the Propeller was opened up and released under GPL 3.0, along with the mask ROM and an interpreter for the Propeller-specific language, Spin. This release is not only a great educational opportunity, but a marvelous occasion to build some really cool hardware as [antti.lukats] is doing with the Soft Propeller.

[antti]’s Soft Propeller is based on the Xilinx ZYNQ-7000, a System on Chip that combines a dual core ARM Cortex A9 with an FPGA with enough logic gates to become a Propeller. The board also has 16MB of Flash used for configuration and everything fits on a Propeller-compatible DIP 40 pinout. If you’ve ever wanted to play around with FPGAs and high-power ARM devices, this is the project for you.

[antti] already has the Propeller Verilog running on his board, and with just a bit more than 50% of the LUTs used, it might even be possible to fit the upcoming Propeller 2 on this chip. This build is just one small part of a much larger and more ambitious project: [antti] is working on a similar device with HDMI, USB, a MicroSD, and 32MB of DDR2 RAM. This will also be stuffed into a DIP40 format, making it an incredibly powerful system that’s just a bit larger than a stick of gum.

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