Restoring A Vintage Computer And Its Plotter

September 22, 2025 by Bryan Cockfield 23 Comments

Repairing vintage computers is bread-and-butter for many of us around here. The machines themselves tend to be fairly fixable, assuming spare parts are available and there hasn’t been too much physical damage. Peripherals can be another matter, though. Since they interface with the real world they can have more esoteric problems that aren’t always solvable. [joekutz] was handed just such a device in the form of a CE-150 docking station for a Sharp PC1500 Pocket Computer, which has a plotter built in. Here’s his “tip” for getting plotters like these working again.

The first step here is to disassemble the original, dried out pens to scavenge a few of the parts. The outer case needs to be kept so that it can be put back into the plotter, and a small O-ring is saved as well. To replace the dried-out tips [joekutz] discards the original tips and replaces them with tips from a common ink pen, using shrink wrap tubing to help fit the pen’s tip into the original plotter cylinder. He also takes the ink from the pen to fill the plotter’s cartridge, completing the surgery on the multi-colored plotter and bringing it back to life.

Of course this build goes well beyond the plotter, including bringing the PC1500 back to life as well. There are a few other videos about this project covering that original restoration as well as demonstrating some of the quirks of how this computer is meant to be programmed. But we mostly focused on the plotter here since that is a little bit out of the ordinary, and we’re also sure that refilling ink cartridges of any sort gets under the skin of everyone at HP.

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New Pens For Old Plotters

March 23, 2024 by Jenny List 17 Comments

Finding consumables is an ever-present problem facing anyone working with old computer hardware. Many of these devices ceased manufacture decades ago and what old stock remains is invariably degraded by time. [Retrohax] has encountered it with the pens for an Atari plotter, a machine that uses an ALPS mechanism that appears in more than one 1980s machine. The original pens had dried out beyond the ability to refill, so he takes us through the process of finding replacements.

Sadly there are no equivalent modern pens ripe for modification, so whatever replacement he used would have to involve a little lateral thinking. He thought salvation was at hand in the form of multicolor ballpoint refills of the type where the ink is in an easily cuttable plastic tube. [Retrohax] and was able to make a 3D-printed holder for a cut-down ballpoint refill. Sadly the pressure required for a good line from a ballpoint was much higher than the original pens, so he was back to square one. Then he happened upon gel pens and tried the same trick with a gel pen refill. This gave instant success and should provide a valid technique for more than just this ALPS mechanism.

If you haven’t got a classic plotter to hand, never fear. You can have a go at making your own.

This Arduino Pen Plotter Is Built For Speed

June 19, 2022 by Dan Maloney 20 Comments

We see a lot of simple pen plotter projects around here, and while we appreciate them one and all, most of them are a little on the slow side. That’s OK — a glacial pace is sometimes all that’s needed, as long as it gets the job done. But there’s nothing wrong with putting the pedal to the metal, so to speak. And that’s exactly what this super-fast Arduino-based plotter is all about.

As the story goes, [IV Projects] felt the need for speed after building an earlier pen plotter project that worked, but failed to excite. With the additional goal of keeping the plotter easy to build with cheap parts, the design centers on a “grit roller drive” for the Y-axis — the one that actually moves the paper back and forth. And move it does, using Dremel tool sanding drums on a lightweight shaft to maximize acceleration. In fact, all the moving parts are kept as lightweight as possible, and the results really show — the three steppers really sing when this plotter is in action.

There are some really clever details in [IV Projects]’ design. We particularly like the way the pen lift mechanism works, and the surprise appearance of a clothespin spring as a belt tensioner was a real treat. Judging by the pile of rejected prototype parts, it took quite a bit of work to get this design right. If you’d like to build your own, STLs are available for the printed parts.

If you’re interested in what the other end of the speed scale looks like, check out this bare-minimum pen plotter.

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Flashpen Is A High Fidelity Pen Input Device

April 1, 2021 by Lewin Day 10 Comments

Pen input has never really taken off in the computing mainstream, though it’s had somewhat of a renaissance in the last decade or so. Various smartphones and tablets are shipping with the technology, and some diehard users swear by it as the best way to take notes on the go. Recently, researchers at the Sensing, Interaction and Perception Lab at ETH Zurich have been working on Flashpen, a high-fidelity pen interface for a wide range of applications.

The fundamental technology behind the pen is simple, with the device using an optical flow sensor harvested from a high-end gaming mouse. This is a device that uses an image sensor to detect the motion of the sensor itself across a surface. Working at an update rate of 8 KHz, it eclipses other devices in the market from manufacturers such as Wacom that typically operate at rates closer to 200Hz. The optical sensor is mounted to a plastic joint that allows the user to hold the pen at a natural angle while keeping the sensor parallel to the writing surface. There’s also a reflective sensor on the pen tip which allows cameras to track its position in space, for use in combination with VR technology.

The team show off the device being used in several ways, primarily in VR tasks, but also in simple handwriting and coloring work. It’s a project that could readily be replicated by any eager experimenter by gutting a gaming mouse and getting down to work; our writers will expect six of your submissions by June 1st to the tipsline. Those eager to learn more can check out the project paper, and may also find the team’s TapID technology interesting. Video after the break. Continue reading “Flashpen Is A High Fidelity Pen Input Device” →

Pen Plotter Draws Maps Directly On The Wall

January 19, 2021 by Dan Maloney 22 Comments

For map-lovers like [Christopher Getschmann], poring over a quality map can be as satisfying as reading a good book. Good maps can be hard to come by, though, especially at a scale worth looking at, or worth using as adornment on a dull, lifeless wall. The solution is obvious: build a wall-mount CNC plotter to draw maps directly on the wall.

[Christopher] began his map quest by scraping world map data from a number of sources, including OpenStreetMap, Natural Earth, and GEBCO. This gave him data for coastlines, terrain, and bathymetry — enough for a map of the world large enough to fill a wall. Since the scale of the map would preclude the use of even a large-format inkjet printer, [Christopher] set about building a wall-covering pen-plotter to render the map. The CoreXY-style plotter is large, but still light enough to hang on the wall while it works, and to be repositioned to cover a larger area.

The plotter runs on steppers driven by ultra-quiet Trinamic TMC5160 drivers, so the plotter wouldn’t be a nuisance while it worked. The map was plotted on eight pieces of cardboard mounted directly to the wall, filling the 2- x 3-meter space almost entirely. Landmasses and elevation contours were plotted as continuous lines in black ink, while bathymetric data was rendered in blue ink as cross-hatching with variable spacing, to make deeper oceans darker blue.

We find [Christopher]’s map breathtaking, all the more so considering the work that went into making it. It would be interesting to find alternate uses for the plotter, which reminds us a little of a cross between a draw-bot and a Maslow vertical CNC router, now that it’s done with its cartographic duties.

Hacking A 3D Pen For Better Performance

January 13, 2021 by Bryan Cockfield 9 Comments

When 3D pens first became available, many assumed them to be gimmicky or part of a general fad that would eventually die out. Like most revolutionary technologies, though, they’ve found a firm foothold, especially in the art community where the ability to 3D print in freehand is incredibly valuable. There are still some shortcomings with the technology, though, but [tterev3] recently tore into a 3doodler pen to make some necessary upgrades.

First, this pen has some design choices that are curious, to say the least. The cooling fan runs regardless of temperature, and it has pushbuttons for start and stop rather than a momentary button that controls the extrusion. To fix these issues, as well as change the filament size, improve the cooling, and provide greater control over the extrusion speed, [tterev3] completely rewrote the firmware, changed the microcontroller on the PCB, and made several hardware upgrades to accommodate these changes. He also went ahead and installed a USB-C port for charging, which should be standard practice on all low-voltage consumer electronics by now anyway.

The detail work on this project is impressive, given the small size of the pen itself and the amount of precision hardware needed to make the changes. Especially regarding the replacement of the microcontroller on the board itself, which is an impressive feat even without the incredibly small dimensions. The firmware upgrade is available on his GitHub page as well if you have your own 3doodler that needs modifications, and if you’re still struggling to find uses for these handy devices, we’ve seen them used with interesting effect to build drones.

Tech Hidden In Plain Sight: The Ballpoint Pen

December 17, 2020 by Kristina Panos 125 Comments

Would you pay $180 for a new type of writing instrument? Image via The New York Times

On a crisp fall morning in late October 1945, approximately 5,000 shoppers rushed the 32^nd street Gimbel’s department store in New York City like it was Black Friday at Walmart. Things got so out of hand that fifty additional NYPD officers were dispatched to the scene. Everyone was clamoring for the hottest new technology – the ballpoint pen.

This new pen cost $12.50, which is about $180 today. For many people, the improved experience that the ballpoint promised over the fountain pen was well worth the price. You might laugh, but if you’ve ever used a fountain pen, you can understand the need for something more rugged and portable.

Ballpoint pens are everywhere these days, especially cheap ones. They’re so ubiquitous that we don’t have to carry one around or really think about them at all. Unless you’re into pens, you’ve probably never marveled at the sheer abundance of long-lasting, affordable, permanent writing instruments that are around today. Before the ballpoint, pens were a messy nuisance.

A Revolutionary Pen

A ballpoint, up close and personal. Image via Wikipedia

Fountain pens use gravity and capillary action to evenly feed ink from a cartridge or reservoir down into the metal nib. The nib is split in two tines and allows ink to flow forth when pressed against paper. It’s not that fountain pens are that delicate. It’s just that they’re only about one step above dipping a nib or a feather directly into ink.

There’s no denying that fountain pens are classy, but you’re playing with fire if you put one in your pocket. They can be a bit messy on a good day, and the cheap ones are prone to leaking ink. No matter how nice of a fountain pen you have, it has to be refilled fairly frequently, either by drawing ink up from a bottle into the pen’s bladder or inserting a new cartridge. And you’re better off using it as often as possible, since a dormant fountain pen will get clogged with dried ink.

Early ballpoint pens were modeled after fountain pens, aesthetically speaking. They had metal bodies and refillable reservoirs that only needed a top-up every couple of years, compared to once a week or so for fountain pens. Instead of a nib, ballpoints have a tiny ball bearing made of steel, brass, or tungsten carbide. These pens rely on gravity to bathe the ball in ink, which allows it to glide around in the socket like a tiny roll-on deodorant.

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