DIY Newton’s Cradle Uses Parts Designed on a Smart Phone

Injection Molded Parts

As far as physics demonstrations go, the Newton’s Cradle is probably one of the most recognizable. Named after Sir Isaac Newton, the Newton’s Cradle demonstrates the law of conservation of momentum using swinging ball bearings.

[Scorchworks] decided he wanted to build his own Newton’s Cradle. The frame appears to be cut from MDF or particle board and then screwed together. That material is really easy to obtain and also to work with using inexpensive tools. The tricky part was the ball bearings. Most of the time when you see a Newton’s Cradle, the ball bearings have a small hole drilled in the top with an eye hook attached. The string is then attached to the eye hook.

[Scorchworks] decided to do something different. His plan was to make custom injection molded plastic rings that would fit perfectly around the ball bearings. The most interesting thing is that he designed the injection molding plates entirely on his smart phone while at his child’s baseball practice. To do this, [Scorchworks] used his own Android app, ScorchCAD. ScorchCAD is a free clone of OpenSCAD that is designed to run on Android devices. Most of the functionality of OpenSCAD has been implemented in ScorchCAD, though not all functions work yet. You can find a list of all the supported functions on the project’s website or in the Google Play store.

Once the plates were designed within ScorchCAD, [Scorchworks] exported the STL file and then used Meshcam to generate the gcode for his CNC milling machine. Once he had the plates machined, he just placed the ball bearing into the mold and injected the molten plastic around it. The plastic formed a perfectly shaped ring around the bearing with small loops for the string. [Scorchworks] repeated the process several times to get all of the ball bearings finished.

Finally, the bearings were strung up using some fishing line. A Newton’s Cradle is very sensitive to the positioning of the ball bearings. To account for this, [Scorchworks] tied each end of the fishing line to two different screws on top of the cradle. This way, each screw can be tightened or loosened to adjust the position of each ball bearing.

Building a CNC Milling Machine for less than $1300

CNC milling machine

[Mynasru] tipped us about a homemade CNC milling machine that his friend [trochilidesign] recently made. We have to admit it may be one of the best ones we’ve featured so far on Hackaday, mainly due to its elegant design (see picture above) and its all metal structure with linear guide rails. In the very well detailed write-up, we can gather that the CNC machine was designed using SolidWorks.

The main frame is built around 2 Maytec 40x80mm profiles and 2 endplates made from 10mm thick aluminum. 3 Nema 23 stepper motors and their drivers power the build, all of them bought on ebay. Finally, the Mach3 CNC software was chosen to interpret the G code and send the appropriate control signals.

Due to licensing restrictions the original author can only provide us with PDF files detailing each part of the machine, but we’re sure this should already be enough for interested persons out there.

CNC 3020 Router gets a Power Supply Upgrade

CNC3020 Router power supply upgrade

We’ve covered these CNC 3020′s in the past. They are physically solid machines but the electronics offer some room for improvement. [Peter] is certainly no novice at working on these machines. He’s already fixed a failed power supply and he’s back at the upgrades, again focused on the power supply. This time he’s replacing the transformer-based one with a couple switching power supplies.

The stepper controllers and spindle speed circuit need both 48 and 24 VDC. [Peter] purchased two separate power supplies, one for each voltage required. Before installing the new supplies, the stock one had to be removed, along with the transformer. Even with the old parts removed, there was still not enough room for both new supplies to be installed inside the stock case. [Peter] decided that mounting them to the top of the case would be appropriate.

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CNC Zen Garden

 

Meet the second version of [David's] sand manicuring CNC machine. We saw version one about six months ago which he built for a science museum in Canada. This offering is much the same, except for the controller. The initial version demanded a full-blow computer to drive it but now that has been swapped out in favor of a Beaglebone Black.

The software has no feedback on the position of the plotter, which is an aluminum slug that [David] machined at Calgary Protospace. It needs to be in a specific position when the machine starts out, and from there patterns are traced by calculating how much spooling or unspooling of the four strings will move the slug.

There’s a bunch of other really neat art installations and projects on [David's] webpage, it’s worth clicking through!

Plotterbot Drawing Daleks

 

Two strings, two motors, and some very creative software. That’s the magic behind the Plotterbot, which was drawing Daleks when we crossed its path at Maker Faire. This is the Mark II, which was built after cannibalizing Mark I. Unfortunately we can’t tell you what the difference is between the two.

The machine itself is a pretty nice little package. There is a box that hangs on the wall with a motor/spool combination at each end. In the middle of those two is an Arduino Mega with a custom driver shield. It takes an SD card with the drawing files on it. There is also a small touchscreen display which allowed for easy selection of what you’d like drawn on that paper taped to the wall below the unit.

Back when we were running the Trinket contest [Jay] used the Plotterbot to draw a Skull and Wrenches made out of a multitude of smaller Skull and Wrenches. He was nice enough bring that piece of art and present it to us at the Faire. Thanks [Jay]!

Running Minecraft On Two Routers

router

[CNLohr] is no stranger to running Minecraft on some weird hardware. Earlier, he built this Linux powered microscope slide… thing to toggle LEDs with redstone levers in Minecraft. Figuring if Minecraft could run on an AVR, he decided to try the same thing on a router, a TP-LINK TL-WR841N to be specific. Like the microscope slide running Linux, this proved to be an easy task. [CNLohr] had another router he could run Minecraft on, and this one could also punch wood. There really was only one thing for him to do.

Like the microscope slide and the wireless router, [CNLohr]‘s CNC router is now running a Minecraft server. The phrase, “because it’s there” comes to mind. When connected to the CNC server, the player controls a snow golem (a snowman with a jack ‘o lantern head) with a carrot. Wherever the snow golem goes, the tool head follows, allowing him to carve objects in the world, and on a sheet of MDF secured in the CNC machine.

It’s certainly an odd build, but [CNLohr] was able to carve out a pixeley, blocky Hackaday logo with the snow golem controlled CNC machine. Code here, video below.

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Ancient TV Remote Becomes a CNC Pendant

DIY CNC Pendant

Needing a control pendant for his CNC machine, [Bob Davis] took to his scrap bin and started looking for parts. What he came up with is pretty cool — that’s a rather old Zenith TV remote providing the enclosure!

When building a homemade CNC machine, many people overlook one of the most handy components — the control pendant. On a commercial machine, they can get pretty pricey — on a homemade machine, most people just use the computer to control it, but if you’ve used a pendant before you know how handy they are for manual operations!

So what should you do? Well, you could make a second dedicated keyboard for your CNC machine (arguably not much of a hack, but rather clever) — or you could build a pendant from scratch like [Bob] did. It’s pretty simple; he’s using a 555 timer, a few momentary toggle switches, an LED, and plans to add a potentiometer in the future for speed control. It’s all housed in the old TV remote, and seems to do the trick just fine — take a look in the following video:

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