If you grew up in a snowy climate, chances are you’ve ridden a sled or toboggan when you were young. The downhill part of sledding is great fun, but dragging the thing back up gets boring quickly. [Luis Marx] had been dreaming of sledding uphill since he was a child, and decided to make his dream come true by building himself a motorized sled (video, in German, embedded below).
The sled is powered by two DC electric motors driving a continuous track, like a rudimentary snowmobile. The motors were originally designed for electric bikes, and can develop 30 newton-meters of torque each. [Luis] designed and 3D-printed a custom set of drive wheels to link the track to the bike motors. Two motor controllers enable basic speed control, while a beefy battery carries enough juice for multiple trips up and down a slope.
The motorized track is mounted on a clever frame that can swing up or down and is held in place by two spring-loaded pins. This way, you can simply lift the system off the snow when you’re ready to slide downhil, and swing it down again when you want the sled to do the pulling.
With winter nearing its end, the snow near [Luis]’s home in southern Germany was too soft to get much traction, but subsequent tests in a ski resort up in the Alps showed the system working perfectly. It even had enough traction to pull a second sled behind it. Perhaps some proper suspension could make it go faster on the downhill run, too.
While you might have bought the best pair of skis in the 90s or 00s, as parts on boots and bindings start to fail and safety standards for ski equipment improve, even the highest-quality skis more than 15 or 20 years old will eventually become unsafe or otherwise obsolete. There are plenty of things that can be done with a pair of old skis, but if you already have a shot ski and an Adirondack chair made of old skis, you can put another pair to use building one of the fastest sleds we’ve ever seen.
[Josh Charles], the creator of this project, took inspiration from his father, who screwed an old pair of skis to the bottom of an traditional runner sled when he was a kid. This dramatically increased the speed of the sled, but eliminated its ability to steer. For this build [Josh] built a completely custom frame rather than re-use an existing sled, which allowed him to not only build a more effective steering mechanism for the skis, but also to use bicycle suspension components to give this sled better control at high speeds.
It’s a ski-based design, and [Josh]’s goal from the outset was to build a rig with serious handling credentials. His favored run features several 180 degree switchbacks, so it’s important to be able to corner well without losing speed. This was achieved by using sidecut skis with a carefully designed steering system, allowing the sled to carve corners in the same way as a downhill skier. The frame of the sled is built out of aluminium box tubing, bolted together to form a strong structure. There’s also attractive wooden decking which completes the look.
The project starts with toboggan style plastic sled. [Peter] built a frame into the plastic using an aluminum square. The frame is used to support a motor pod at the back of the sled. The motor, of course, comes from his DIY electric plane project. Don’t worry — [Peter] didn’t cannibalize his plane. The plane’s motors are being upgraded, and this is one of the originals.
The motor itself is quite a beast. It’s a 150cc equivalent brushless outrunner motor from HobbyKing. It’s not cheap either at around $450 USD. The motor is controlled by an equally beefy brushless controller wired into a standard R/C car receiver. A pistol grip transmitter makes a great wireless throttle for the system.
Steering is a much more mechanical affair. The sled’s rudder is controlled much like that of an airplane. A steel cable pull-pull system is connected to a stick mounted in front of the pilot. The unreinforced styrofoam rudder turned out to be a weak point in the build — check out the video after the break to see the full story.
Next time you’re taking a vacation anywhere that resembles the planet Hoth, you might want to take the time to build a snow speeder sled before you go. As you can see in the video above (at around the 1:00 mark), the sled looks great, even as it “flies” down the slopes. We were fairly surprised to find it was made entirely out of cardboard. We were also fairly surprised at how large the person was that unfolded from the cockpit when it stopped!
[Unihopper] built this sliding camera mount to add some motion to his freestyle unicycle videos. It’s extremely simple, but still pulls off a pretty nice effect as you can see in the clip after the break.
The image above shows the mount without a camera attached. You can see the threaded peg on the block in the foreground which is used for that purpose. Felt has been wrapped around the base of the block, which rides in a wooden channel. The string, which connects to an eye hook in the wood block, is attached to a spool on the far end of the plank. A K’nex motor drives that spool, slowly sliding the camera toward it.
Here’s a camera mount that moves smoothly along a motorized sled. [Bart Dring] created the system and was surprised by it’s popularity, having received several sales requests from photographers. He originally designed the linear bearing system, called the MakerSlide as an inexpensive alternative to other CNC machine solutions. Allowing a computer to map out timed movements for video shots wasn’t on his radar then, but as you can see in the clip after the break, the MakerSlide does an amazing job at it.
The modular track system makes it easy to attach to a base. In this case, a couple of pieces of acrylic let him support both ends of the track on standard camera tripods. [Bart] mentions the knowledge gap between people who work with CNC milling hardware and photographers as an issue in deciding how to control the system. Since photographers aren’t likely to be proficient in EMC2, he designed a control application with an Arduino. It uses a stepper motor controller shield, and does some fancy math to make sure there is smooth acceleration, etc.