Go ahead, browse the archives.
It took me more than a couple of minutes to find this, so for future reference, the package that provides raspistill, raspivid, and raspiyuv is libraspberrypi-bin.. This is primarily for raspbian-ua-netinst which doesn't install it by default.
I’m working on a project using Atmel’s ATXMega series of microcontrollers, which are quite a nice step up from the ATMega series. They’ve been out for a few years, but aren’t very widespread, and here are the best overviews I’ve seen if you’d like to read up on them.
PDF Slides: XMEGA intro_2010.pdf mirror via
Video from linux.conf.au in 2012: David Zanetti, XMEGA Internals (CC-by-SA, or, youtube link at 56:55 in; original is from videos page)
I just realized I forgot to write anything about last year when I put together the Mantis bot 9.1. Cutting took a little planning, but I made it out of a single 2 × 4 sheet with almost no waste and all the remaining pieces are useful for building a second copy. While I didn’t make it for <$100, I did learn quite a bit about what matters for a small CNC machine like this and probably could get the incremental cost to $200 if I built more than one.
The single most expensive parts are a 3/8-12 ACME tap ($80ish) used for making the leadscrew nuts, and the electronics (the Mantis site assumes you can manufacture them yourself, which requires… a bot, or toner transfer (which I haven’t had good luck with)). I was able to use some older reprap boards, which connected with test clips to my parallel port. To date I haven’t had a short, although the clips do tend to fall off.
As you can see from the photo up top, I made it out of plywood with a thinner outer layer than spec’d. This is because MDO is comparatively difficult to find, but you can find 12mm cabinet plywood at a place like Lowe’s or Home Depot. I’ve since found a local lumberyard that stocks MDO in precut 2 × 4 pieces, which I plan to go with for my next project.
Although I understand one of the primary goals was to make a really inexpensive machine, there are several points that I feel could be improved for an additional couple percent in cost.
So far I’ve done basic engraving with it using a V bit in cardboard and plywood, some drilling with PCB bits, and attempted to make a couple of circuit boards using a 1/64 endmill. My biggest lesson learned so far is that if you crash the bit into your work piece without it spinning, the tip will break.
When I pick it up again next, I plan to construct something more stable for electronics (if I want to keep using EMC2, a parallel breakout board with Pololu drivers; if separate, something based on the reprap Gen7 boards). I’d also like to build a larger one, the ~6 × 4” area is pretty limiting.
I discovered these while assembling my derivative of the Printrbot. Links go to photos that are part of the Printrbot Detail album.
Even with all that, my bot is still a kludge. I have lots of binder clips holding parts on, and the main board isn’t even screwed down to anything. The Printrbot isn’t a ready-to-go kit, but it may well be the best repstrap in terms of availability to print the bot you want to end up with long term.
Earlier this year, I got wind of the Printrbot 3-d printer kit. After the Kickstarter was funded, but (well before) it shipped, Brook released the source files under an open source license, so I found someone who could print me a set. A common problem in hobby 3-d printers is the chicken-and-egg problem: most reprap printers incorporate printed parts, so how do you get started?
Anyway, after very slowly assembling the v1 parts, there are obviously a few places that the design could be improved. Answering question I had myself before building (based on building a “Pro” sized 8 × 8 with plastic parts, rather than lasercut):
The allowance for the lower motors is enough for average size motors, but not some large ones that I had on-hand.
The homing switches are necessary, despite the fact there weren’t any v1 printed parts to hold them. The X one (on the upper left) will get a fair bit of stress because it moves up and down. With the output from Slic3r it needs to home all axes before each print and the X axis again only after it finishes (this could be substituted with a G0 X0 with the same effect), so I need to hold the wire carefully to make sure it makes contact.
Initially I tried a press-fit plastic Y pulley, but it would get soft after a lot of use and slip. With Eric’s help last weekend I replaced it with an aluminum one, and it’s much more accurate now. The only Y problems that remain are from the way the belt pulls it, and the fact the belt is off center. The X axis is using a printed pulley with setscrew, and I haven’t had any trouble from it. The X idler is a little tricky to get right, I ended up mixing a 5/16” bolt I could find locally with a mix of metric and SAE washers.
The space provided for tensioning belts is basically useless; you need to remove an idler, zip-tie to tension, then reassemble.
After completing my build, I started to consider what I’d want in a printer if I started from scratch. The main points, Y axis riding on stationary rails and a belt path like Mendel has (which requires an extra idler), more airflow around the Y motor, something more rigid to hold the top of the Z axis, and printed parts that allow for easier-still customization, all seem to be design goals of Nophead’s Mendel90. For people starting out, I’d suggest that rather than a Printrbot (if you can get someone to make you the necessary parts).
