Planet Arduino

[Neumi] has built a CNC Laser using CD-ROM drives as the X and Y motion platforms. The small 405nm laser can engrave light materials like wood and foam. The coolest use demonstrated in the video is exposing pre-coated photo-resist PCBs.

With $61 US Dollars (55 Euro) for the Arduino, stepper drivers, and a laser in the project, [Nuemi] got a pretty capable machine after adding a few parts from the junk bin. He wanted to avoid using existing software in order to learn the concepts behind a laser engraver. In the end, he has a working software package which can send raster scans to an Arduino mega. The mega then controls the sync between the stepper and laser firings. The code is available on GitHub.

The machine can do a 30x30mm PCB in 10 minutes. It’s not about to set a record, but it’s cool and not at all bad for the price. You can see the failed PCBs lined up in the video from the initial tuning, but the final one produced a board very equivalent to the toner transfer method. Video after the break.

A couple of old DVD ROM drives and a compact photo printer is fairly standard fare at the thrift store, but what do you do with them? Hack them up to make a CNC foam cutter of course!

[Jonah] started with a couple LITE-ON brand DVD RW drives, which use stepper motors instead of plain old DC motors. This is a huge score since steppers make accurate positioning possible. With the internal frames removed, threaded rod and nuts were used to hold the two units parallel to each other forming the Z axis.

The feed mechanism from a Canon compact photo printer was then bolted onto the bottom to form the Y axis. Add a bit of nichrome wire for the cutting element (this can be found in old hair dryers) onto where the laser assembly of the DVD rom once lived, and you have the mechanics done.

Control is handled by an Arduino and some easy-driver modules to interface with the steppers. G-Code is generated by CamBam, which handles various cad files, or has its own geometry editor.

This is a fantastic way to get your feet wet in several ways; Cracking things open to harvest parts, driving steppers with simple micocontrollers, modeling and generating g-code, etc. The one issue we see with this build is a chicken-or-egg problem since you need to have a cube of foam cut down to somewhat strict dimensions before it will fit in this cutter. But we suppose that is really just an iterative design problem.

Sometimes you just know from the photo that this is going to be a really cool project. When most people salvage parts from an old printer, they usually chuck the rest. In this case [Shane] made use of the entire printer to build his CNC machine.

He started with an old HP 2500C A3 printer, which he had planned to salvage for parts only. While he was taking it apart he realized the chassis would make a great frame for his actual CNC machine! With that in mind he quickly changed his game plan to making each axis inside of the printer.

He’s using regular ball bearing drawer runners for both the X and Z axes, covered with a clever design of aluminum angle to keep any possible chips from jamming them. The Y axis on the other hand makes use of the original shaft runners from the print head carriage. Each axis is driven by threaded rod using recycled stepper motors from the printer.

An Arduino UNO sits at the heart of the project with a Protoneer CNC shield to control the stepper drivers. He’s also included an emergency stop, hold, resume, and cancel buttons for manual control.

It’s a great project, and an amazing example of using what is on hand for a project. Stick around after the break to see a demonstration of it printing!

[Thanks Kruger!]

[Dan Royer] has noticed that most university projects involving a Stewart platform spend more time building a platform than on the project itself. He hopes to build a standard platform universities can use as the basis for other projects.

Stewart platforms are six degree of freedom platforms often seen hefting flight simulators or telescopes. The layout of the actuators allows movements in X,Y,and Z as well as pitch, roll and yaw. While large platforms often use hydraulic systems to accelerate heavy loads quickly. [Dan] is looking at a smaller scale system. His platform is built of laser cut wood and uses six steppers to control motion.

One of the harder parts in designing a platform such as this is creating a mechanical system that is strong, precise, and smooth. With so many linkages, it’s easy to see how binding joints could bring the entire thing to a grinding halt. [Dan] is currently using RC helicopter ball joints, but he’s on the lookout for something even smoother.

For locomotion, stepper motors are more than adequate  - providing both the quick acceleration and holding torque needed to control the platform. Adafruit’s stepper motor controller boards provide the drive from an Arduino. The bottleneck in all of this is the i2C link with control of 6 steppers limiting the overall speed of the platform.

Software is another big issue on Stewart platforms. Kinematics of 6 DOF platforms are no easy task. To this end, [Dan] has gone open source. His Gcode demo is available at github.

By the time you get to the point in a home CNC build where you’re adding control electronics you may be ready for the simplest means to an end possible. In that case, grab your Arduino and heat up that etching solution to make your own GRBL compatible shield.

This familiar footprint manages to contain everything you need for a three-axis machine. The purple boards slotted into the pairs of SIL headers are Pololu Stepper motor drivers. Going this route makes replacing a burnt out chip as easy as plugging in a new module. The terminal block in the center feeds the higher voltage rail necessary for driving the motors. The DIL header on the right breaks out all of the connections to the limiting switches (two for each axis), spindle and coolant control, as well as three buttons for pause, resume, and abort. There’s even a header for SPI making it easier to add  custom hardware if necessary.

This is a dual-layer board which may not be ideal for your own fabrication process. [Bert Kruger] posted his Gerber files for download if you want to put in a small run with OSH Park or a similar service.

This Predator suit was premiered at this year’s Monsterpalooza conference. It’s nothing short of incredible. But the shoulder cannon is really what caught our attention. The thing is fully motorized and includes sound and light firing effects.

We saw a glimpse of what [Jerome Kelty] is capable of about two years ago. He was showing off an Arduino-based animatronics platform he put together for a Predator shoulder cannon that tracked based on where the predator’s helmet was pointing. But other than a video demonstration there wasn’t much info on the that actual build. This post makes up for that and then some.

A replica of this quality is rarely the work of just one person. A team of fans joined in to make it happen. After getting the molded parts for the backpack and canon from another team member [Jerome] set out to fit the support structure, motors, and control electronics into the space available. That meant a ton of milling, cutting, and shaping parts like the support arm seen above which integrates a servo motor into its rectangular outline. All of the controls fit in the backpack, with cables running to the helmet, as well as the cannon.