I'm moving in with my girlfriend, which means purging certain things in the name of love. Therefore I'm giving away two old pen plotters and a mid-century modern Danish sewing cart. They're all free, but the catch is that you'll have to pick up your desired item before February 1st 2015 at my place. Contact me at email@example.com if you're interested. First come, first served.
Hewlett-Packard 9872C "OctoPen" Prototype from the 1970's
I bought this from a retired HP engineer on a dark night in a deserted parking lot in the outskirts of San Jose back in 2010. I'm not sure it was ever supposed to leave HP's labs. It worked once via a USB to HP-IB adapter I got off eBay, and I haven't been able to communicate with it since. I'm not sure if it's a software thing or if the hardware is off – it only has an HP-IB port on the back, no RS-232 or any other fancy stuff. The buttons on the front panel work fine, and the plotter can still select pens and move them around if you use the arrow keys. Maybe there's a way to hack directly into it, I haven't really looked into it. In any case it's an interesting historical object or a good source of some really high quality motor parts.
It has a super cool electrostatic paper holder that sucks the paper down at the push of a button – it might also mess up your pacemaker in the process. It also has a few undocumented buttons that the production version didn't have, as well as the project mascot, an octopus, stamped on the front panel. If you need to impress an older HP engineer, this is the plotter to have in your collection.
It comes with a broken paper bag filled with manuals, full spec electrical diagrams and other nerdy stuff, but no power cable as far as I remember – those are cheap though.
Houston Instruments 2000 Analog XY plotter
This guy is pretty cool. It's an analog pen plotter from, I believe, the late 60's. Each axis maps to a configurable voltage range, for instance 0-5V. The X-axis can also do a time sweep, if you're into that. I used to run it with an Arduino and two 12-bit DAC's, which gave me a resolution of 4,096 x 4,096 on A3 paper. Using higher resolution DAC's will give you higher resolution output. It holds the paper down with air suction, kind of like an inverted air hockey table. It'll hold most pens, if you use some duct tape. It's super fast, noisy and very old-school. It doesn't come with anything except for the power cable and a few wires wired into the pen up/down switch.
You can see a glimpse of it in action here, around the 1:10 mark:
Mid-century modern Danish sewing cart
I just don't really have a need for this thing. It's a sewing cart made in Spøttrup, a town in Denmark mostly known for its not-so-impressive castle. It has four caster wheels, a pull-out bag kind-of-thing that could use some new fabric, and a drawer with lots of little compartments. The top could use a little love, but otherwise it's in pretty good condition.