Tennis Ball Launcher Has Puppies Running the 100m Dash

Launching Tennis Balls with Ease

[Brian] from 24 Hour Engineer has a friend with arthritis who can’t easily play ball with his new puppy — so [Brian] stepped in and built him this awesome tennis ball launcher.

You see, most tennis ball launchers require a solid flick of the wrist, and since just plain old throwing it is out of the question too, [Brian] had to make him something powerful and easy to use. After sketching out some designs he came up with the basic concept that eventually became what is pictured above.

The frame is made of 2″ PVC pipe, which serves two purposes, support, and safety. The bungee cord launching system is actually contained within the pipe, keeping it out of the way, and free from catching on anything during firing. A pair of pulleys mounted at the cord opening ensure the cord doesn’t wear out.

What we really like is the trigger mechanism [Brian] made out of some carefully cut wood,  a steel corner brace and a few nuts and bolts. It’s a simple mechanism that provides leverage and an easy way to release the bungee cord.  Continue reading “Tennis Ball Launcher Has Puppies Running the 100m Dash”

Hackaday Links: February 2, 2014

hackaday-links-chain

[Michel] was in need of a 9V battery connector, and in a brilliant bit of insight realized 9V batteries will plug directly into other 9V batteries (just… don’t do that. ever.) Taking a dead 9V, he tore it open, was disappointed by the lack of AAAA cells, and soldered some wires onto the connector.

Sometimes a project starts off as a reasonable endeavour, but quickly becomes something much more awesome. [Wallyman] started off building a hammock stand and ended up making a giant slingshot. We’re not one to argue with something that just became a million times more fun.

We’ve seen solder stencils made out of laser-cut metal, photoetched metal, plastic cut on a vinyl cutter, laser-cut plastic, and now finally one made on a 3D printer. It’s a pretty simple process – get the tCream layer into a .DXF file, then subtract it from a plastic plate in OpenSCAD.

Apple loves their proprietary screws, and when [Jim] tried to open his Macbook Air with the pentalobe screwdriver that came with an iPhone repair kit, he found it was too large. No problem, then: just grind it down. Now if only someone could tell us why a laptop uses smaller screws than a phone…

[Victor] has been playing around with an RTLSDR USB TV tuner dongle for a few months now. It’s a great tool, but the USB thumb drive form factor wasn’t sitting well with him. To fix that, he stuck everything into a classy painted Hammond 1590A enclosure. It looks much cooler, and now [Victor] can waterproof his toy and add a ferrite to clean things up.

GoPro Slingshot

Want to try out aerial photography, but can’t afford a quadcopter? [Jeremy] rigged up a low cost GoPro Slingshot and took some pretty nice flyover shots of the lake.

The slingshot itself is meant for water balloons, but easily has enough power to fire the camera. In order to get good video, some stabilization was needed. [Jeremy] made a stabilizing fin out of packaging foam, and used an eye bolt to connect it to the GoPro’s threaded tripod mount. The simple tail fin made of out foam and zip ties actually did a good job of stabilizing the camera.

This looks like a fun experiment to try when you’re at the lake, since you can probably build it with stuff lying around the house. For [Jeremy], it also proved to be a way to keep his dog entertained since she retrieved the camera after each shot. After the break, check out the video footage from the GoPro slinging rig.

Continue reading “GoPro Slingshot”

USB slingshot controller is for the birds

This USB slingshot controller really brought a smile to our faces. Part of it is the delightfully silly promo video you’ll find after the break. [Simon Ford] combined nature and technology to bring this USB-enabled slingshot into existence.

The frame itself is from a branch he found in the Epping Forrest of London. He whittled away the bark, and hollowed out an opening in at the base of the ‘Y’ to receive an accelerometer board. It has a pair of female pin headers to interface with the mbed seen in the image above. But the real hack here is the code he wrote to translate accelerometer data into appropriate mouse movements. His success in the area makes this translate the virtual world of Angry Birds in a visceral experience of killing things with a slingshot.

We’re suckers for this type of project. Two examples that pop into mind are these musical instrument hacks for Rock Band 2.

Continue reading “USB slingshot controller is for the birds”

Crazy slingshot guy at it again with a 220 lb steel ball cannon

80mm_slingshot_cannon

Good old [Jörg Sprave].

That guy just doesn’t quit building insane slingshots. If he’s not honing his machete slinging skills in preparation for the zombie apocalypse, he’s blowing out car windows with giant steel balls.

The huge cannon you see above is modeled off a small slingshot he made a while back, which fired 8mm steel bearings. In its larger form, the slingshot is said to be ten times the size of it’s smaller brother, firing 80mm steel balls with incredible force. In the video below, [Jörg] and his friends cart the slingshot out to a huge empty field where they run it through its paces on several different objects. Their first shot flies about 220 yards into a high tension tower, after which the boys aim their sights on an old car.

The power with which the slingshot fires is definitely impressive. With a few well-placed shots, the car is pretty much done for.

Now that we’ve seen [Jörg] fire off saw blades, machetes, and giant ball bearings, we can’t wait to see what comes next!

Continue reading “Crazy slingshot guy at it again with a 220 lb steel ball cannon”

“Stupid expert” builds a machete slingshot for the impending zombie apocalypse

machete_slingshot

Sometimes people build things for the simple challenge of building. This is one of those cases.

The gentleman you see in the image above is [Jörg Sprave] of The Slingshot Channel. He is a self-proclaimed “Supid Expert” on the subject of slingshots and has taken his love of flinging things at absurd velocities to a whole new level.

His latest creation is a machete slingshot, which is really more accurately described as a machete crossbow. Measuring over six feet long, the impressive apparatus fires a specially altered machete with an insane amount of force using thick rubber bands. In the test firing shown in the video below, the machete is embedded up to the hilt in six layers of very thick cardboard, requiring quite a bit of work to remove.

As he states in the video while brandishing his bloodied forearm, building such a device is extremely dangerous, and should be limited to “Stupid Experts” . In no way should you attempt to build one of your own.

Continue reading ““Stupid expert” builds a machete slingshot for the impending zombie apocalypse”

How to properly dispose of fruitcake

While doing serious fruitcake research, (no, really) we stumbled across the Great Fruitcake Toss held every January in Colorado. The particular entry above caught our eye. Omega 380 was built by a group of Boeing engineers and currently holds the distance record of 1,420feet. It’s a large compressed air cannon. All pressure is human generated using an exercise bike turning a pump. Apparently the team’s first contest entry was a classic surgical tubing slingshot. It eventually broke down during a very cold year, so they switched to this newer design. You can see more videos on the Operation Fruitcake blog.