Making cheap HP plotter pens + yet another HP-GL viewer

If you’re running an old plotter, getting pens can be a worry. While there are some companies that might still make them (Graphic Controls/DIA-Nielsen, for one) they are expensive and limited in range. They’re also felt-tip, which means they’ll dry out if not carefully re-capped.

While eBay might supply all things (like these Roland DG plotter pens I scored a couple of days back; fine, black, new old-stock, or these German plotter pens), I also found this:

$_3It’s described as “11.5*28MM cutting plotter vinyl cutter pen holder 50mm for Roland holder Pcut”. I bought two, and eventually the slow boat from China came …


The one on the left is an unmodified pen holder. Well, it’s really a ballpoint-refill holder, as it comes with a (random colour of blue) refill.  To modify these to fit into an HP desktop plotter, you will need to:

  1. Cut ~10 mm from the end of the holder. A Dremel + cutting disk is a satisfying way of doing this. The gap between the knurled bit and  the thread seems to be a decent place. Clean up the sharp edges
  2. As the knurled lock ring will stop the pen engaging in the carriage (my HP-7470A does a lovely little hesitant try… nope; try… nope; try… give up sequence), you’ll have to do without it. Find another way of jamming the threads of the threaded collar in the right place. I used electrical tape, and it’s held so far. Wiser users will use different colours of electrical tape for different pens, ahem …
  3. Stick the pen refill in and tighten down the collet lightly with pliers. ¡¡¡ Do not try to pull the refill out while it is in the collet !!! (The ballpoint insert will likely pop out, and viscous ink will start to blort out everywhere. Ask me how I know!)
  4. Snip the end of the refill flush with the end of the pen holder using diagonal cutters. Best to do this directly over a rubbish bin, as pen ink is nasty. Dab off excess ink from the end of the refill, and clean your cutters, too.
  5. The base of the threaded collar should be around 29 mm from the pen tip, otherwise nothing will plot (if it’s too short) or you’ll poke holes in the paper (if too long). This measurement doesn’t seem to be extremely critical: my Roland pens have it at 28.5 mm, the DIA-Nielsen pens are 28.9 mm. One of my homebrew pens is working at 30½ mm, but then, my basic plotter has no force control, so it may be more forgiving than more elegant beasts.

modified holders and cut/not-so-cut refills

My modified pens look like the above.

The dollar store is a good source of cheap ballpoint pens. I managed to snag 8 retractable red pens for $1.25, and 4 black pens for $1.

one of the donor red pens, plus the disassembled pen holder

(These retractable pens more often than not eject the whole internals across the room when you retract ’em.)

It’s probably a good idea to scribble with the pens a bit before and after modifying them, as they take a while to flow freely. They plot very lightly; the black ink looks more like a faint pencil line.

Double-plotted nested bézier curves
Double-plotted nested bézier curves

If you look close up, not merely are the lines very faint, but something else important shows up:

double-plotted detail, showing off-centre effects (actual size 17 × 17 mm)
double-plotted detail, showing off-centre effects (actual size 17 × 17 mm)

The lines — which should be a constant(ish) distance apart, if the paper has stayed in registration — are showing a varying distance from each other. It looks like the pen points are a little off-centre, so when the pen is swapped out, it gets turned to a slightly different position. This would really only matter for precise work, and I find the effect interesting.

As for the HP-GL viewer? GhostPDL, by the makers of Ghostscript. You’ll have to build it from source, and its documentation isn’t quite where one might want it to be, but it implements a full HP PCL6  / HP-GL/2 interpreter than can output bitmaps, PostScript or PDF. The SVG graphic below was made using the tools/ script to convert HP-GL to PDF, then I used ghostscript to convert that to SVG. Nifty!

weave.pltAs a bonus, GhostPDL comes with one of the prettiest plotter fonts ever:

The strange world of the 808 Car Keys Micro Camera

They have no viewfinder, no way of focusing, no controls beyond a power button and a multi-function shutter button (and two other seemingly useless buttons). They come with no manual, no readily identifiable manufacturer and you don’t really know what you’re going to get until you turn them on — yet they sell in their thousands. They are the 808 Car Keys Micro Camera.

I first heard about them from This Camera is an Adventure on MetaFilter, then someone suggested one as a solution to my Halfbakery idea “Tiny high quality digital camera”. So I bought two:

  • a #3 from ebay seller liangmin9888. Total cost $14.59 shipped from Hong Kong.
  • a #16 from ebay seller elehomegood. Total cost $40.99 shipped from Hong Kong.

I chose these sellers for their high reputation, and they didn’t disappoint. The cameras? They’re no Leicas.

The #3 is supposedly the best of the standard resolution cameras. They have a large yellow timestamp permanently inscribed in the corner of any image or video. The one I have is loaded with lens aberrations, and makes a Lomo look like a view camera. Still, I see some potential in it.

The #16 is a bit better. It still is miles behind my phone camera, and it only takes slightly soft 0.9 megapixel images. No video samples yet, but here’s a squinty picture I took in Lakefield today:

Lakefield, rather wonkily by 808 #16

I do feel a bit self conscious about using such a covert camera, but I’ll see what I can do with them.

cheap databases for Mac

Apparently they all use the wonderful SQLite, too.

Make your own 120 Film Cans

I wrote this ages ago, but it wasn’t in the easiest to find place. I discovered today that Ilford fit inside Agfa, and – with a bit of brute force – an Ilford will fit inside an Ilford. So I made a few more of these …
I’ve often wondered why the relatively tough little metal-clad 35mm roll comes in a neat plastic case, while the bigger and more delicate 120 roll has nothing more than foil to protect it. You can buy 120 film cans, but they are expensive after-market things.

Since I also (used to) shoot 35mm, I tend to end up with a lot of empty film cans. Some brands of film, I noticed, have quite different can diameters. Fuji seems to have the narrowest, Ilford next, and then Agfa the widest. A Fuji can slips quite neatly inside an Agfa can — in fact, if you bore a small hole in the bottom of an Agfa, fill it with water, and slide a Fuji can in as a plunger, it acts as quite an effective single-shot water pistol. But I digress …

But best of all, I discovered that a Fuji can is a tight interference fit into an Ilford can. Since I knew that a 120 spool is a smaller diameter than a 35mm roll, and is less than twice the length, I knew I could do something with this.

ilford and fuji film cans, knife.

You will need:

  • an Ilford film can. It doesn’t need to have a lid, as it will be acting as the base of the “stretch” 120 can.
  • a Fuji film can. I’ve only used the black kind you get with the faster films. I suspect that the clear cans that are used on the rest of the range might work, but won’t be light-tight.
  • a sharp knife. The pictured Opinel may not look much, but it has a razor-like carbon steel blade.

fuji can with end sliced off.

Slice the end off the Fuji can. It helps to poke a hole in the side of the can a couple of millimetres up from the end, and then start slicing where you made the hole.

fuji can jammed in ilford can.

Jam the now baseless Fuji can into the Ilford can, and push it down to the desire length. It really helps if you take the lid off the Fuji can, as otherwise you’d be working against air compression. It also helps if you have a spare 120 spool handy, to check that you haven’t pushed the two cans too far in to be useful.

120 film can in use!

And there you are! It might be rather rough and ready, but it works. I don’t know how durable or waterproof these things are, but they’ll afford considerably more protection than having them rolling about loose in your camera bag.

scrummy scran from the HAL Burgers man

I really like HAL Burgers (244 Adelaide). Good burgers, clever decor and decent beer. Not the cheapest burger I’ve ever had, but one of the better ones.

Update, August 2007: oh no, it’s closed! Notice of Distress on doorway dating back to July, so again I’m the last to know.

nostalgia for something that never existed

The Verbatim FlashDisc seems to be a solution without a problem to solve.

verbatim flashdisc

It’s a cheap ($4) but very tiny (16MB) USB memory key in the vague form of some kind of magnetic media. There are problems:

  • $0.25/MB may seem cheap, but it would mean that a 1GB key at this price was $256
  • It neatly blocks most of the USB ports on a machine
  • Just what kind of media is it supposed to be? It looks closest to an old spool of mag-tape, but folks buying this wouldn’t remember that.

Maybe it was too easy …

Configuring the rest of the Sempron box has been a slog. It seems that there isn’t a single wireless adaptor that works with 64-bit Linux. I might have to resort to a wireless ethernet adaptor, like the D-Link DWL-G820. They’re not cheap, but they may be the only option.

the computer does not work

My 4 year old Athlon XP box finally gave up this week. It had been acting ropily for a few months, and now it won’t even boot. Don’t really need to replace it with anything powerful; maybe just a cheapo Sempron box. We’ll see what Canada Computers has to offer.

a joy forever

a thing of beauty

I finished fixing up the brakes on the Super Galaxy, and put new handlebar tape on the bars. I still suck at fitting bar tape; should’ve stuck to my old standard Benotto tape, which, while almost useless for shock absorption, is cheap and easy to fit.

Once all was fitted, I took it for a spin. The new brakes are a delight; very positive and extremely powerful. I will enjoy riding again.

(And yes, you bike nerds, there is no straddle cable in that picture.)

zeiss it ain’t

fish sculpture

For no good reason, I bought a very cheap ($20) mini digital camera at the airport. Its limitations make it quite fun to use:

  • has the astonishingly high resolution of 352 x 288
  • fixed-focus lens chock-full of chromatic and spherical aberration
  • no display, except for a cryptic 2-digit LCD
  • takes 20 images, then it has to be downloaded
  • grossly inaccurate viewfinder, which shifts when you press the shutter button
  • images have pronounced scan lines
  • refuses to take images in low light
  • weird non-standard USB connector

It is very small, and can also work as a webcam. It also works as well as it could under OS X (use macam to download the pictures, or enable the webcam). Using the webcam does seem to delete the pictures, so make sure you download ’em first.

I’ve made a minicam gallery, which I’ll add to until the novelty wears off.

Happy Nuke Day!

Yup, Chernobyl was 20 years ago. Let’s just have a wee pause for a technology that’s still messing us up, yet we’re told it’s the green technology of the future. Yeah, and I bet it’ll be too cheap to meter, too.
There are still farms in Scotland affected by the fallout from Chernobyl. Though, what with all the nuke plants in Scotland, it could be any one of them that’s the real culprit.

Now, if you’ll excuse me, I’ve got a wind farm to survey …

Tax Time

Phew – that’s the 2005 income taxes filed for Catherine and me, and also my GST return in. I don’t grudge paying taxes (no civilization without taxation, after all), but I hate filling out the returns. I’m also too cheap to get someone to do it for me. Sucks to be me, eh?

The week of shaving carefully

So how did my first week of shaving with a plain safety razor go? Pretty well, I think.

I’ve discovered that Weleda shaving cream and after-shave balm work well for me. They have a muted, natural scent, and are very soothing.

What didn’t work for me was Lush Prince shaving cream. This heavy, waxy preparation clogs up the blade, it smells too strongly of neroli, and is a horror to rinse off. I also cut myself the only time I used it. Styptic pencil owies resulted.

Catherine has remarked on the closer shave (I suspect ‘cos I’m spending more time on it). It’s strange, but the stubble seems sharper. I wonder if multiple blades smoothed the razor-cut ends of the hairs, and thus gave an impression of a smoother, longer-lasting shave?

I like my Merkur. Using it for a year will end up cheaper than any cartridge razor, and result in far less trash.

just yer basic yerba, mate

Scored some yerba mate for Catherine’s cousin Phil yesterday. Seems there aren’t so many South American food stores in KCMO, while there’s a strip of them on Augusta in Kensington Market.

The store at 239 Augusta had a whole yerba mate section. Since it was cheap ($2 for the half key), I got some for myself. Wonder what I’ll do with it?

cheap powermeter

I snagged a UPM EM 100 Energy Meter at crappytire yesterday. It was a good bit cheaper than the old standard P3 Kill A WATT. We’ll see if it’s useful.

(So I guess I’ve answered my own Talk Energy post.)

happy desktop

Did some upgrades/maintenance to the Linux box tonight:

  • added a DVD±RW drive
  • finally fitted the cheapo Zalman fan controller to take the edge off the CPU fan noise
  • got X11 working with the nVidia graphics card again, under 2.6.14. It was fiddly.

Some people might wonder why I keep maintaining a 3½ year-old Athlon XP1800+. It works, and with the amount of RAM I have in it, it’s plenty fast.

look ma, no wires!

I’ve finally got rid of the ethernet cable that snaked across the kitchen floor to this linux box. A cheapo wireless PCI card (TRENDnet TEW-423PI, from CWO) plus ndiswrapper, and we’re laughing.

I hate Sony

While I like my Cybershot P100, I can’t believe that Sony would make the Memory Stick Pro incompatible with older Memory Stick readers. It’s bad enough that Sony had to created their own expensive, proprietary memory card format (which does exactly what better than CF or SD?), but to make it incompatible between revisions of itself is beyond inexcusable.

Y’see, I scored a cheapo Lexar multi card reader from CWO the other week because it was quite small and takes both CF and MS. I discovered this evening, when it failed to read my MS Pro cards (in the adaptor) but happily read my mum’s plain MS card, that the two formats are gratuitously incompatible. Um, hello, earth to Sony R&D …