A 3D(ollar) Scanner

scanner

Once you have a 3D printer, making copies of objects like a futuristic Xerox machine is the name of the game. There are, of course, 3D scanners available for hundreds of dollars, but [Joshua] wanted something a bit cheaper. He built his own 3D scanner for exactly $2.73 in parts, salvaging the rest from the parts bin at his local hackerspace.

[Josh]‘s scanner is pretty much just a lazy suzan (that’s where he spent the money), with a stepper motor drive. A beam of laser light shines on whatever object is placed on the lazy suzan, and a USB webcam feeds the data to a computer. The build is heavily influenced from this Instructables build, but [Josh] has a few tricks up his sleeve: this is the only laser/camera 3D scanner that can solve a point cloud with the camera in any vertical position. This potentially means algorithmic calibration, and having the copied and printed object come out the same size as the original. You can check out that code on the git.

Future improvements to [Josh]‘s 3D scanner include the ability to output point clouds and STLs, meaning anyone can go straight from scanning an object to slicing it for a 3D printer. That’s a lot of interesting software features for something that was basically pulled out of the trash.

Changing Unipolar Steppers To Bipolar

steppers

If you’ve been a good little hacker and have been tearing apart old printers like you’re supposed to, you’ve probably run across more than a few stepper motors. These motors come in a variety of flavors, from the four-wire deals you find in 3D printer builds, to motors with five or six wires. Unipolar motors – the ones with more than four wires – are easier to control, but are severely limited in generating torque. Luckily, you can use any unipolar motor as a more efficient bipolar motor with a simple xacto knife modification.

The extra wires in a unipolar motor are taps for each of the coils. Simply ignoring these wires and using the two coils independently makes the motor more efficient at generating torque.

[Jangeox] did a little experiment in taking a unipolar motor, cutting the trace to the coil taps, and measuring the before and after torque. The results are impressive: as a unipolar motor, the motor has about 380 gcm of torque. In bipolar mode, the same motor has 800 gcm of torque. You can check that video out below.

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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]!

A 3-Axis Paper Cutting Mini Laser

LaserCutter

Laser are awesome, and so are projects that use lasers. A recent Instructable by [kokpat] gives an overview of how to create a fully functional laser paper cutter using CDROM stepper motors and an Arduino.

What is special about this build, is that it showcases how easy it can be to build a 3-axis mechanical system used for laser cutters, CNC machines, and 3D printers. Using a stepper stage that consist of a motor screw with a nut slider based carriage, the mechanical system can be put together quite easily and cost effectively. Luckily, from an electronics and software perspective, everything is quite standardized with the proliferation of the RepRap and similar machines. Simply pick any three stepper drivers, find the most pertinent firmware, and voilà! You’re done! Well, almost. Don’t forget a 100mW violet laser!

We have seen a ton of really cool laser cutters before, but this has to be one of the cheapest. See the laser cutter in action after the break.

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A Reel To Reel Clock

And this is how the clock will tell time!

Word clocks – time pieces that spell out the current time with words – are awesome. They’re usually entirely electronic, illuminating LEDs to display the time. Not this one. It’s a mechanical masterpiece that shows the current time in words using motors and 35mm film leader.

The mechanics of this clock are fairly simple: text is transferred onto 35mm film leaders with water slide decals, which are then rolled onto film reels. These film reels are mounted on stepper motors attached to a frame with Meccano. There are four film strips, making this a surprisingly similar a word clock but using motors instead of LEDs.

Because this clock was originally built in 2008, the electronics are a bit… strange through the lens of a post-Arduino skill set. [David] is using a homebrew BASIC Stamp with eight Step Genie ICs and MOSFETs for each motor. Calibration of the clock is handled by an IR detector and a mark on each piece of film leader.

It’s an impressive example of mashing up spare and surplus parts to make something cool, but unfortunately we can’t find a video of this clock in action. If you manage to find one, put a link in the comments and we’ll add it below.

Converting a Mill to CNC

traces

Have a mill that you’d like to automate? Perhaps you can gets some ideas from the work [James] recently finished. Using familiar NEMA 23 stepper motors (the same motors used in the RepRap), he hacked his Proxxon MF-70 mill for CNC control. Adding a Sanguino and the stepper controllers from other projects, [James] got a working machine for minimal investment. You can tell that [James] is a fan of Polymorph, because he uses it liberally for most of the project, even using it to create some Oldham couplings (Google cache).

After completing the build initially, he managed to burn out the spindle motor by milling steel too quickly. We found it interesting that he was able to use a TURNIGY 2217 860kv 22A Outrunner (for R/C airplanes) as a new spindle motor. Not only is it a low-cost solution, but pairing it with a traditional brushless ESC can give your CNC software direct control over the motor speed.

The image above is an example of what [James'] machine is capable of. Overall, it’s a very accessible project for most of us. Not every mill needs to be capable of 10 mil traces. If you’ve got the urge, you can probably put one together yourself. Of course, if you do, please let us know!

Walter is a Robot Head Built From Scratch.

walter

[Chris] has put together a robot head that is impressive at first sight. [Chris’] robot, Walter II, becomes even more impressive when you realize that [Chris] built every single part from scratch. Many of Walter’s parts were created using machines [Chris] built himself. Walter is a robot neck and head. His upper neck joint is based upon three bevel gears.Two steppers drive the side gears. When the steppers are driven in the same direction, Walter’s head nods. When they are driven in opposite directions, the head turns. The end result allows Walter’s head to be panned and tilted into almost any position.

A second pair of motors raise and lower Walter’s neck via a chain drive. What isn’t immediately visible is the fact that a system of gears and belts maintains the tilt on Walter’s head as his lower neck joint is actuated. For example, if Walter’s head is facing directly forward with his neck raised, one would expect him to be facing the ground when the neck is lowered. The gear/belt system ensures that Walter will still be facing forward when the neck joint reaches its lower limit. All this happens without any movement of the neck motors. [Chris] definitely put a lot of thought into the mechanical design of this system.

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