3D Printing Pen and CNC Machine Yields Cheap 3D Printer

3D printers are ubiquitous now, but they’re still prohibitively expensive for some people. Some printers cost thousands, but even more inexpensive options aren’t exactly cheap. [Daniel] decided that this was unacceptable, and set out to make a basic 3D printer for under $100 by including only the bare essentials needed for creating anything out of melted plastic.

3D printers are essentially four parts: a bed, filament, and a hot end and extruder. In a previous project, [Daniel] used parts from old CD drives to create a three-axis CNC machine which he uses for the bed. To take care of the hot end and extruder, he is using a 3D printing pen which he mounts to the CNC machine and voila: a 3D printer!

It’s not quite as simple as just strapping a 3D printing pen to a CNC machine, though. The pen and the CNC machine have to communicate with each other so that the pen knows when to place filament and the CNC machine knows when to move. For that, [Daniel] went with a trusty Arduino in order to switch the pen on and off. Once it’s working, it’s time to start printing!

[Daniel] does note that this is a design that’s relatively limited in terms of print size and resolution, but for the price it can’t be beat. If you’re interested in getting started with 3D printing, a setup like this would be perfect. 3D pens are a pretty new idea too, and it’s interesting to see them used in different ways like this.

Pneumatic Pen Gun is Fit for James Bond

The James Bond franchise is well-known for many things, but perhaps most important to us hackers are the gadgets. Bond always had an awesome gadget that somehow was exactly the thing he needed to get out of a jam. [hw97karbine’s] latest project would fit right into an old Bond flick. He’s managed to build a single-shot pellet gun that looks like a pen.

[hw97karbine] started out by cutting the body from a tube of carbon fiber. He used a hacksaw to do the cutting, and then cleaned up the edges on a lathe. A barrel was cut from a piece of brass tubing with a smaller diameter. These two tubes will eventually sit one inside of the other. A custom front end cap was machined from brass. One end is ribbed and glued into the carbon fiber tube. The barrel is also glued to this end of the front cap, though it’s glued to the inside of the cap. The other end of the cap has 1/8″ BSP threads cut into it in order to allow for attachments.

A rear end cap is machined from Delrin. This piece also has a Delrin piston placed inside. The piston has a small piece of rubber used as a gasket. This piston valve is what allows the gun to operate. The rear cap gets glued into place and attached to a Schrader valve, removed from an automotive tire valve stem.

To pressurize the system, a bicycle pump is attached to the Schrader valve. This pushes the piston up against the barrel, preventing any of the air from escaping. The piston doesn’t make a perfect seal, so air leaks around it and pressurizes the carbon fiber tube. The Schrader valve prevents the air from leaking out of the pen body. A special machined button was threaded onto the Schrader valve. When the button is pressed, the air escapes; the sudden pressure imbalance causes the piston to shoot backwards, opening up a path for the air to escape through the barrel. This escaping air launches the projectile. The whole process is explained better with an animation.

Now, the question left in our mind: is this the same pressure imbalance concept that was used in that vacuum pressure bazooka we saw a couple years back?

Continue reading “Pneumatic Pen Gun is Fit for James Bond”

Scribble: Wait, Kickstarter Is Vetting Projects Now?

PenFirst rule of reading anything: if a headline is an interrogative, the answer is a resounding ‘no’. This might be the one exception to that rule.

This Kickstarter is actually fairly interesting. Not because it’s an obvious scam, mind you, as there’s very, very little to actually call a scam. It’s noteworthy because it was on track to be a highly successful campaign but it was shut down by the creators just days after its launch.

Before getting to the unsavoriness of this Kickstarter campaign, a little bit of history is in order. Several years ago and before crowd funding was a thing, a designer came up with a rather clever if completely improbable idea: a color picking pen. Simply hold the end of a pen up to an object, press a button, and using technology and/or magic the pen now writes in that color. There are obvious shortcomings in the design like using red, green, and blue ink cartridges for color mixing – a classic case of confusing additive and subtractive color models. Still, this is just a design concept and over the years the idea of a color sensing pen that mixes ink has bounced around the Internet. With enough people willing to throw money at their screens in the hopes of actually getting a product as interesting as this, you just know it’s going to be on Kickstarter sooner or later.

Enter the Scribble Pen. Yes, it’s the same idea as the 5+ year-old color picking pen, with a few of the technical challenges already addressed. They’re using a CMYK (plus White) color model that can theoretically reproduce just about any color, and do so on any color paper. How are they doing this? I have no idea, but the whole campaign is super, super sketchy.

Continue reading “Scribble: Wait, Kickstarter Is Vetting Projects Now?”

A Robot’s Favourite Pen

A test of various pens using a robot

Some people are very picky about their pens. Entire forums exist to discuss the topic of pen superiority. However, it comes down to a personal choice. Some people like gel while others prefer ballpoint.

[Jens] built a drawing robot that produces drawings like the one seen here. It uses several linkages connected to two stepper motors, which give fine control over the pen. With the robot working [Jens] set out to find the best pen for robotic drawing.

Seven pens were tested on the machine, each drawing the same pattern. [Jens] found that gel and rollerball pens work the best on the robot, and started examining the performance of each.

The pens all performed differently, but two winners were chosen to use in the machine. The Pentel Energel Deluxe RTX and the Pilot G-2 07 beat out the competition since they maintained good lines at high speeds.

If you’re looking to build a drawing robot, [Jens]’ research should help you pick the best pen for your application. For inspiration, a video of the robot in action is waiting after the break.

Continue reading “A Robot’s Favourite Pen”

CNC ping pong printer uses simple construction


This is one of the simplest CNC builds we’ve seen but it still functions quite well. It’s a clone of the EggBot, but is aimed at printing on spherical Ping Pong balls rather than oblong eggs. [Chad] calls it the Spherebot, but you should be careful not to confuse it with the morphing sphere robot which can walk around like a hexapod.

The project is both mechanically and electronically simple. The body of the printer is made up of three acrylic plates, which we’re sure were clamped together when drilling holes to guarantee proper alignment. Threaded rod and nuts are used to mount the plates to one another, as well as to hold the sphere in place while printing. One stepper motor turns the ball while the other pivots the pen mount. A servo motor is responsible for lifting the pen. The entire thing is driven by an Arduino along with two stepper motor driver boards. Don’t miss [Chad’s] presentation embedded after the break.

Continue reading “CNC ping pong printer uses simple construction”

Handwriting suck? Build a machine to do it for you


Children of the information age are doomed to have the worst handwriting just for lack of use if nothing more. But some students at Olin College harnessed technology to find a solution to that problem. Meet Herald, a CNC machine that can produce beautiful calligraphy.

The machine uses a gantry to move the writing tip along the X and Y axes. The flexible-nib calligraphy pen is mounted on a sprocket which rotates the tip onto the writing surface, taking care of the third axis. The rig was beautifully rendered from their CAD drawings, then tweaked to ensure the smoothest motion possible before the quintet of Sophomores began the physical build.

The drive hardware is very simple yet it produces great results. It uses an Arduino along with three stepper motor drivers. There are also limiting switches to protect the hardware from runaway code. The software interface designed by the team lets the user cut and paste their text, and select a font, font size, alignment, etc. It then converts the text to G-code and pushes it to the Arduino where the GRBL package takes care of business.

Don’t miss the device in action, writing out a [Langston Hughes] work in the clip after the break.

Continue reading “Handwriting suck? Build a machine to do it for you”

Self-feeding pen printer

At first look we thought this was a plotter, but it’s really more of a dot matrix (or line matrix) printer. [Bruno] whipped this up using parts from a DVD optical drive. It is capable of moving the pen along the Z and X axes, and feeding the paper along the Y axis.

The video after the break shows the machine printing Megaman, an image perfectly suited to the low-resolution pixels this can put out. But even without the high-pixel counts you might get from a thermal printer, we just love the look of this one. And who doesn’t have an optical drive sitting around just waiting to be hacked? It looks like the one part you’re going to have to source is the stepper motor and geared feed wheel that moves the paper.

Continue reading “Self-feeding pen printer”