http://www.fabhub.net/blog.php This is a discussion forum powered by vBulletin. To find out about vBulletin, go to http://www.vbulletin.com/ . en Thu, 17 May 2012 22:29:22 GMT vBulletin 60 http://www.fabhub.net/images/misc/rss.jpg http://www.fabhub.net/blog.php http://www.fabhub.net/blog.php?b=32 Tue, 03 May 2011 16:53:00 GMT Image: http://farm6.static.flickr.com/5029/5683640777_208809b7a2.jpg (http://www.flickr.com/photos/quadshop/5683640777/) Here is a minimal, first...

Here is a minimal, first version of Duinolab. It has an Arduino, 4 buttons, 6 LEDs, and 2 potentiometers. Each peripheral is connected to an I/O pin on the Arduino, but can be turned on or off (via I2C). When off, it is electrically neutral, and the user can use that pin for something else.

The Arduino pins are broken out to the central breadboard, which is easily removable/swappable to allow the same Duinolab to be used for multiple projects.

The hardware design is at http://duinolab.googlecode.com/svn/trunk/hardware/

The software is still in progress, but will include an Arduino library and sample code. I'll talk more about that when I finish it.


The front panel design is clearly not quite there yet... but that will come with the next version, where I will engineer the circuit boards so that the connectors and chips are on the bottom, and the controls/LEDs/whatever can be mounted on top.

In addition to a nicer faceplate, also to come in the next version:
- Reset buton and power switch (with cool cover)
- LiPo battery and charger/boost converter
- Graphical LCD with 4 menu buttons (eventually to be replaced with this)
- Speaker, microphone, and photoresistor
- True rainbow LEDs (need purple/violet!) ]]> jmanton http://www.fabhub.net/blog.php?b=32 http://www.fabhub.net/blog.php?b=30 Wed, 06 Apr 2011 16:26:28 GMT So I tend to be a bit disorganized. Usually I live with this fact. But things got to a breaking point last week.

I hadn't done much experimenting with electronics for several months because I'd been doing the polyhedral models stuff. But I was going to be doing some stuff with the guys at Makerspace Urbana, on the Great Global Hackerspace challenge. And I needed to find some parts to use for a hacking session. I wanted my Arduino, my MakerBot extruder controller (old school 2.2), some switches and knobs and a little joystick I got from SparkFun. I also wanted a protoboard and my neat prototyping wires (everybody should have these because they are awesome).

But I couldn't find everything. I couldn't even find most of the things. I spent 30 minutes going through all of my electronics crap, and I only found parts of it here and there. It was 3 days before I was able to track down everything (including stuff that was in a bag under the drill press in the garage... I said I was disorganized).

Enough is enough. I don't want to have to spend time sorting and organizing and searching when I just want to hack some quick project together on the Arduino. So I came up with the idea of the duinolab. The concept is a small document case that closes up (like this), fits in your laptop bag, and has all the stuff that you would want to mess with an Arduino-based electronics project, in one easy-to-store, easy-to-transport, easy-to-use package. It is inspired by the Radio Shack Electronics Learning Lab, which I used to first learn electronics more than 10 years ago (and I still use from time to time even today, because it is just so darn convenient).

Here is a gratuitous picture of my inspiration for this:

The case would include the Arduino and a prototyping board. It would also have an LCD display, 8-segment LED displays (driven by a dedicated chip), discrete LEDs with current-limiting resistors, buttons, switches, potentiometers, rotary encoders, joystick, speaker (with low-current amp), and microphone. Some space would be left open based on individual interests, like an XBee, motor driver, RC servos, or sensors. It might even have a low-current adjustable power supply and rechargeable battery pack, to allow the project to run without being connected to the laptop. Everything would be mounted in some way, so the case can simply be closed and put away for easy storage and/or transport. If you had several (e.g., at a makerspace or fablab) it means they can be easily stacked or stored without having to break everything down.

There would be space inside the case to store prototyping wires, and a small amount of storage for discrete components and chips for use on the protoboard. You could close the case without disturbing your protoboard - all the wires would fit.

Oh, and the protoboard itself would be on a carrier with a ribbon cable attachment to the rest of the board. At any time you could take out the protoboard (without breaking down your current project), and put in another. So if you are in the middle of one project and have an idea for something else, you can just swap back and forth. Duplicating just the protoboard (and a couple of connectors) costs a lot less (by an order of magnitude) than duplicating the whole thing.

I would probably use an Arduino Mega for this. That way everything can be permanently hooked up to the "extra" I/Os on the board, and the normal 19 Arduino I/Os are left free. If I did this I'd also have an Arduino library that allows you to easily access all the little peripherals without having to figure out the pinouts, read the data sheet, or whatever.

It would be kind of cool to build in a place to store a Bus Pirate and/or Open Logic Sniffer (both are awesome, by the way). But maybe then things are getting a bit crowded... ]]> jmanton http://www.fabhub.net/blog.php?b=30 http://www.fabhub.net/blog.php?b=29 Tue, 11 Jan 2011 19:04:55 GMT Image: http://farm6.static.flickr.com/5006/5346960258_78313e2bf9_m.jpg (http://www.flickr.com/photos/quadshop/5346960258/) Image:...

Today was my last enrichment activity with the kids from my daughter's school (6th graders). For our last project we put together a stellated dodecahedron with the property that for any face you look at, the star is the same color (I'm not explaining that well - look at the pictures to see what I mean). Each of the kids got their own "kit", and three of the six had the figure complete or almost complete in just one class period (43 minutes), with the rest about half way done.

The models are made up of twelve different "spikes", each of which is its own piece of paper.



One of the problems with making paper models of stellated polyhedra is it is a lot harder to make the concave joints with flexible paper, especially as you get to the last few parts of the model. You just can't get your fingers in the right place to put tabs in place or to hold things together to properly glue them. And it gets really hard to fit tweezers in to help, since everything is already closed up.

So I made models with holes in the faces. This turns out to make it a lot easier to put them together, as you can get tweezers in the right place without any difficulty. And I think they look pretty cool too :-)

For this model I decided to use tab-and-slot design for the individual spikes, but to use something else to connect them all together. I actually took 1/2" mailing labels, and cut them to length (a sheet at a time). This made nice, white stickers, which made it easy to make a complete kit. The stickers are used to connect the five sides of the base of each of the "spikes" to its neighbors.

Each of the panels in the kit has a different arrangement of colors. You need a little instruction sheet to figure out what connects to what. While it is a bit confusing, I made one of those as well.



The source files are here. There is a uncolored version that has Inkscape files, and PDFs ready to be laser cut. The color ones depend on printing and then cutting with registration marks, so all of those files are in Silhouette Studio format. No Inkscape for the color ones, though you can probably open the PDFs in Inkscape and get something approximating a native SVG file.

No-color one, can be laser cut (PDF, svg)

Each of the three color sheets with spikes:
sheet1 (PDF, studio)
sheet2 (PDF, studio)
sheet3 (PDF, studio)

Instructions (two sets per page - I just cut them in half):
instructions (txt, docx, PDF) ]]> jmanton http://www.fabhub.net/blog.php?b=29 http://www.fabhub.net/blog.php?b=28 Mon, 20 Dec 2010 07:31:45 GMT I've developed an Inkscape extension to render the polyhedra nets I've been making the last few months. It can make nets for the platonic, archimedean, and archimedean dual solids. There are several options for tabs including tab and slot, no tabs (for showing rather that assembling), and a couple of options for tabs that can be glued.

The nets are pre-colored so that you can use color mapping to get dotted fold lines along with the cut-out outline, as described here.

The code is here, where I keep all my fablab-related stuff.

The relevant files are:
polyhedra_other.inx
polyhedra_platonic.inx
polyhedra_archimedean.inx
polyhedra_archimedeandual.inx

polyhedrondata.py
polyhedra.py

You can either install this for all users on your system (fine if it is a personal desktop or laptop) by copying all 6 of the above files into the inkscape/share/extensions directory where inkscape is installed. Alternately, on Linux, you can copy them into your home directory, in $HOME/.config/inkscape/extensions.

Once it is installed, you need to restart Inkscape (if it was running). Then you should have a submenu called "Polyhedra" under the Inkscape "Extensions" menu. There are several submenus because of the number of solids - it was overwhelming when there were 33 choices in the drop-down menu. ]]> jmanton http://www.fabhub.net/blog.php?b=28 http://www.fabhub.net/blog.php?b=27 Sat, 27 Nov 2010 20:44:27 GMT Image: http://farm5.static.flickr.com/4106/5212526240_47e36b7aab.jpg (http://www.flickr.com/photos/quadshop/5212526240/) Perhaps it is time for...

Perhaps it is time for an intervention? :o

But seriously, Réka and I are having a blast making these things. The really colorful ones in the back are due to an idea by my friend Bruce. We were talking about how it was fun to make the polyhedra, but if you wanted to make one that you didn't have a net for, you had to spend some time making up the net. Now, I've made that easier by writing an Inkscape extension that renders nets (not ready for release, but soon...). But what if you want to make something unusual, like a house for your lego figure?



So, his idea was to make individual panels. We worked out the connector shape (basically a tab and slot next to each other), and voilá! There it was!

I went and bought some colored cardstock, and cut them out on my Silhouette SD machine. Here are some pictures that show a bit better what the panels look like:



Right now there are only files for the Silhouette (in the newer "studio" format, not GSD), which isn't very helpful. I'm going to make up some Inkscape ones tonight or tomorrow, so I can cut a ton of them out on the laser cutter for my enrichment class on Tuesday. The kids said they wanted to make ones with different colors - I think this qualifies :cool: ]]> jmanton http://www.fabhub.net/blog.php?b=27 http://www.fabhub.net/blog.php?b=26 Tue, 26 Oct 2010 16:20:51 GMT Ok, now I think I'm starting to get a bit carried away...



After about 15 iterations I've finally come up with a slot/tab design that allows all these models to go together easily without glue or tape. They work well on both my paper cutter and on a laser cutter. I've tested it with 65lb and 80lb cardstock, and 100lb bristol board, and it works great. For inserting into inkscape documents. Note - the sizes are very specific - if they are resized, the various clearances for the slots have to be adjusted. Here is the file with 1", 2", and 3" tabs and slots: tabs.svg.

I updated the truncated icosahedron (soccer ball) model with the new tabs. My first version of this model (see a couple of posts back) took almost 2 hours to put together with glue and tape. This one took about 15 minutes, and half of that was pre-creasing all the folds.



Here's the file: TruncatedIcosahedron.svg (PDF) ]]> jmanton http://www.fabhub.net/blog.php?b=26 http://www.fabhub.net/blog.php?b=25 Thu, 21 Oct 2010 15:49:31 GMT I bought an inexpensive ($200) paper cutter (http://www.amazon.com/Silhouette-Digital-Craft-Cutting-QuicKutz/dp/B0021VNTMC) online and it arrived... I bought an inexpensive ($200) paper cutter online and it arrived last night. It is slower than the laser cutter, but does a great job building my polyhedron models:



That took about 2 minutes to cut (mostly due to the complex slot design - no tape!), vs. probably 20 seconds on the Epilog. But I have one in my house, rather than only getting to use it for a couple of hours a week ( :mad: ) at the fablab.

The other advantage this has over the laser cutter is that it has a small optical scanner that can find registration marks. So you can print designs that will go on the outside of your model, then put it in the cutter and it will cut along the lines. Pretty cool. ]]> jmanton http://www.fabhub.net/blog.php?b=25 http://www.fabhub.net/blog.php?b=24 Wed, 20 Oct 2010 16:02:30 GMT More polyhedra at the fablab! Image: http://farm2.static.flickr.com/1084/5099863744_3716c59c11_m.jpg ... More polyhedra at the fablab!



The first one is the truncated icosahedron (SVG, PDF), also known as the "soccer ball" (well, the old soccer ball...). Its what you get when you take an icosahedron (20-sided figure made up of triangles), and cut the corners off. Each triangle becomes a hexagon, and all the vertices in the old icosahedron are transformed into pentagons. The funny lines and arrows written on the surface is my attempt to come up with a net that has more room to have better tabs. I'll update the link when I get that worked out.

The second one is the snub cube (SVG PDF). It's what happens when you take a cube, cut off the corners (making triangles), then replace each edge with two more triangles. You end up with squares on the faces of the "old" cube, but they are rotated (and smaller). There are actually two versions of this that are mirror images of each other. I think you could make either one with the same net, simply by having a different side of the paper facing out (not sure though).

The third one is nets of the rhombic dodecahedron (SVG PDF), rhombic triacontahedron (SVG PDF), and the dodecahedron (SVG PDF). I also made models of these, just didn't photograph them yet (I'm at work, models are at home...). The rhombic dodecahedron is a 12-sided figure (dodecahedron) made up of rhombi (rhombuses?) instead of pentagons. It goes together very differently than a "standard" dodecahedron - if you put it together you'll find that some vertices have 3 shapes coming together, and some have 4 coming together. The rhombic triacontahedron is a 30-sided figure made up of the same type of rhombus. The vertices vary between 3 and 5 shapes, depending on if the three larger angles meet or the four smaller meet. The dodecahedron is a 12-sided figure made up of pentagons. I think it could also be called the pentagonal dodecahedron, since the 12 sides are all pentagons. But that would be redundant :-)

The fourth picture is just a jumble, showing that I actually made some with different colors.


I really don't like the tab structure on these - they are waaaaay too hard to put together. I'm going to try to engineer something tomorrow in the lab that makes them easy to put together without glue or tape. We'll see how that goes... If I can figure out a good design for the tabs, I'll replace the ones linked here with new ones with the new tabs in place. ]]> jmanton http://www.fabhub.net/blog.php?b=24 http://www.fabhub.net/blog.php?b=23 Fri, 15 Oct 2010 21:58:56 GMT I've been experimenting with paper cutting at the lab off and on for several months. I decided to start working on cutting out models of Polyhedra. I've been inspired in this project by the website of George Hart and the books of Magnus Wenninger, specifically Polyhedron Models. George Hart is speaking at a conference here in Champaign-Urbana tomorrow, and I plan to go (10am on a Saturday... who's idea was that?). Hopefully I can get some patterns out there for other polyhedra, perhaps using the nets function in Mathematica, or perhaps by exporting data out of the Stella program (which I plan to buy anyway, since it looks cool).

One of the other guys at the lab showed me a neat trick that I used last night to cut out my first model. The trick is to use the frequency setting on the laser cutter to get dashed lines. This is great when cutting out nets of polyhedra to fold - you can cut with one color, and score the folds with another.

Here are pictures of the icosahedron I did last night:



And the source file:
PDF SVG

The fun part about this project was the settings used. I used color mapping, and set it up for red to be dashed lines, with 100 speed, 25 power, and 50 frequency (that's not a typo - fifty for frequency). Blue lines were more standard paper (cardstock) cutting settings, at 85/50/500. This is all on a 50-watt Epilog Mini.

I had a strange problem where after everything was cut out correctly, it would go over a couple of the dashed lines again at the default vector power level and cut them out. It was very frustrating, and for a while I was just hitting the stop button on the Epilog when it finished with the regular cut (when I discovered it was at the default level, I changed the power to 0 and the frequency to 10 by default, so it just went over the lines without cutting).

I spent a lot of time trying to find "hidden" lines, including looking at the SVG source file, and couldn't figure out why it was doing that. But now I think I figured out the problem. The lines in question had the "fill" set to black (these are 2D lines...). This *shouldn't* result in anything being printed, but what was happening is that for those lines, the laser cutter would go back over them with the default power settings.

I think I fixed that in the files linked above. I haven't tried it yet, so your results may vary :-) ]]> jmanton http://www.fabhub.net/blog.php?b=23 http://www.fabhub.net/blog.php?b=22 Mon, 06 Sep 2010 03:46:25 GMT My daughter Reka and I made this in the C-U FabLab last week: Image: http://farm5.static.flickr.com/4151/4962041339_4ea281c0ed_m.jpg ... My daughter Reka and I made this in the C-U FabLab last week:



The design files are at this link: http://jmantonfablab.googlecode.com/...ives/sa_gears/


The design

How we got the design is a fun story. At the FAB6 conference last month I met Pieter Tolmay from the Potchefstroom Fab Lab in South Africa. During the showcase on Thursday night, he was showing some things that they'd made in their lab to help teach mathematics to local kids:



I was particularly interested in the little gear train with the rack and pinion mechanism. Reka has just started middle school, and it seemed like something her school might be able to use when teaching mathematics. Pieter and I exchanged cards, and he sent me the Corel Draw design files for the gear train. This really of exemplifies the spirit of FabLabs worldwide - we design something useful, share it with each other, and something designed in South Africa will end up in my daughter's middle school in central Illinois, USA.

I wanted to make sure that future kids at Reka's school would be able to appreciate that it was designed half-way around the world for kids just like them. So I etched the following text on the base:



It says "Designed at the AMTS FabLab North-West, Potchefstroom, South Africa. Made at the Champaign-Urbana Community FabLab, Urbana, IL, USA September 2010". Then Reka added "From Reka" in a sharpie, to sign her gift.


Making the gear train

Anyway, once I had the file I imported it into Inkscape and made a few minor modifications (etched where the "hub" pieces should attach on the base, etched out some text, and added etched dots on each gear to help keep track of where the gears are). Those modified files can be found at this link. I made a few small changes at the lab, namely rounding the corners of the base plate and breaking all the gears out into different files so I could cut them out of different colors.

The base is made out of 3/16" frosted acrylic, and the gears are made out of various colors of 1/8" clear acrylic. After everything was cut out, I super-glued small pieces to the base so that the gears would have something to rotate on:



Once we had it together and played with it a bit, Reka made some really good suggestions for how we could improve it even more. The first one was that we cut some small cylinders out of the 3/16" acrylic to act as handles on the gears (held on with more super glue):



The second one was to put some feet on the underside of the base, since it was really hard to pick the base up off the table:




Using it to teach math

I'm not a math teacher, so I don't know how to write a lesson plan for this (any volunteers?) but Reka spent some time playing with the gear train, and offered up this starting point (she will show this to her class on Tuesday, when she gets to school).

Arrange the gears with the dots on the two smaller gears right next to each other, and the dot on the yellow gear touching the orange gear, like so:



Move the blue rack gear until the dot on the smallest gear has gone all the way around once, like so:



Now, why aren't the dots lined up any more? What has happened to the dot on the yellow gear? And most importantly, why have these changes occurred? ]]> jmanton http://www.fabhub.net/blog.php?b=22 http://www.fabhub.net/blog.php?b=21 Thu, 02 Sep 2010 17:52:20 GMT Here are some photos of recent projects. I'm sure I'll get to full writeups for all of them... eventually.

Here is the start of the 3D printer Bruce and I are building. These pictures were from last fall (2009), before we put a Dremel tool on it. As of late June 2010, we still haven't finished the extruder, but it has seen a lot of use just with the Dremel as a mini-CNC router.










This is a PCB I made using the aforementioned router with the Dremel tool. It drives an 8x8 bi-color LED array, and displays the game of life cellular automata.




This is the "blinky" project. It is a circuit from an introduction to electronics set from Radio Shack. Réka and I worked together to convert it to a PCB, and then produced it on the router. This project was a lot of fun, even though it was simple.




This is the future extruder controller for the 3D printer/router thing. Bruce and I assembled it from a kit from MakerBot Industries. I was nervous at first, as I had very little experience with surface-mount components. It turned out well in the end.




This is a gear train that I designed using Inkscape and cut out of acrylic at the fablab. The other shots are spare parts and such for mounting the gears. It is sort of a gear construction kit!








This is a photosensor and encoder wheel for a motor. There is one infrared LED, and two phototransistors. The enclosure was designed using that old standby CAD tool vi, in gcode, and cut out on the Dremel router.




These are a couple of attempts at ball bearing joints. I bought bearing balls from McMaster-Carr. The first one is out of MDF, and actually works pretty well. It was also cut out using the Dremel router, with a python program to create the circles in gcode. The clear one was cut out on a laser cutter, and it turned out I cut it out wrong. But I'll make another version... someday.




This was a pain in the ass. It is a 12-sided figure made out of acrylic cut on the laser cutter. Everything is press-fit, no glue at all, and it holds together fine. The biggest issue was that I found out (the hard way) that cast acrylic can vary by up to 30% in thickness across a single piece (!!). Which means only about half of the support pieces I cut actually fit. It was a tedious, frustrating job to get it put together. I have some ideas for ways of making the holes springy, to get around this, if I ever make another one.








This was a project Réka did at the fablab. Over a two week period, she designed a box (using a neat Mathematica program done by another volunteer), and cut out a bunch of small pieces of acrylic to put in the box. This is the result.






This is a model from the book Orgami Architecture. It is cut with an x-acto knife out of a single piece of cardstock. It took a long time, but is pretty awesome.

]]> jmanton http://www.fabhub.net/blog.php?b=21 http://www.fabhub.net/blog.php?b=14 Mon, 16 Aug 2010 18:01:03 GMT I arrived in Amsterdam yesterday for the FAB6 conference. The conference started last night with a dinner in the Tolhuistuin garden, just across the... I arrived in Amsterdam yesterday for the FAB6 conference. The conference started last night with a dinner in the Tolhuistuin garden, just across the IJ waterway from Centraal Station.



The idea of the instructables restaurant was to make a do-it-yourself restaurant based on recipes from instructables.com. The recipes and raw materials were provided, and the participants had to cook their own dinner.

I was initially kind of skeptical - there were lots of "obvious" reasons why this "wouldn't work". But in true fablab fashion the bugs were worked out by the participants, and in the end it was a fantastic evening all around.

It appears that my hotel is metering/throttling the wifi access, so I can't upload the pictures quite yet. But here is the commentary, and I'll add the pictures later today if I can find better network connectivity.

It seems that if there is a climbable tree, people flock to it. This is how the evening started, with a couple of fablabbers perched on top of this tree/staircase.



This tree turned out to be a central location for cooking later on because of the many convenient-height surfaces made by the steps.

The restaurant had lots of raw materials for cooking. Refrigerators with veggies and meat:



Tables with vegetables, spices, and supplies for making marinade:




Recipes from instructables:



And of course, there has to be a way of cooking the food once it is prepared. They supplied personal-sized mini-barbeques for this purpose:




We received information about how to start from the organizers:


The first step was to get the barbeques lit, since the coals take a while to heat up. We were lucky in this whole process in that Gary Watson is a boy scout leader, and had done this type of thing before.







Some people had a bit more trouble getting things going. The sight of people fanning their cooking fires was a common one at first:



One group looked like they were planning to smelt the aluminum rather than cook with the foil:






There were all kinds of configurations of fires. I think this one was my favorite:



Fires started, it was time to start preparing the food:


















Food all ready, time to cook!

(I got tired of linking the pictures - lots more on my page on Flickr)
327, 331, 332, 333, 338, 339, 344, 353, 354, 355, 356, 357, 358, 359, 365, 366, 367, 368,

By this time we were all pretty hungry. But it turned out pretty well in the end:

360, 361, 362, 363, 364, 369, 370

There were a few bugs in the program. Like using wooden tables to cook with personal barbequeues:



All in all it was a great evening! ]]> jmanton http://www.fabhub.net/blog.php?b=14 http://www.fabhub.net/blog.php?b=8 Wed, 11 Aug 2010 05:51:02 GMT So, I built my first PCB completely in the fablab (see thread here (http://www.fabhub.net/showthread.php?14-Modela-for-circuit-boards)). And I got... So, I built my first PCB completely in the fablab (see thread here). And I got it to work to the design. Unfortunately, it isn't working quite how I wanted it to, for a number of reasons.

1) The ICSP programming header doesn't have two pins hooked up in the original design. Neither the VCC or RESET pins were connected to *anything*. This made it, well... kind of hard to program the device. So I soldered a couple of wire-wrap wires to the pins in question. I could then program the device using my STK500 on my Windows PC using AVR Studio.
2) I haven't been able to get the Arduino bootloader to work on the board. I think this is because the device I used was an ATmega88PA, rather than the ATmega168 used in the Fabio. The chips are functionally identical, except for the amount of flash memory. It may be that is the problem, I don't know.
3) The programming instructions for the Fabio are... well, a little light. That's a nice way to put it. The correct way to say it is "they are incomplete". They don't actually talk about programming the bootloader using the ICSP headers at all. So I've been trying to figure out from what they do have there how to program it. And I've been unsuccessful (so far).
4) I like using a Mac laptop when I'm doing stuff at home. I don't actually like sitting at my Windows PC, since it kind of removes me from the activities going on in the house. Until tonight, I couldn't use my mac to program via the ICSP port because I didn't know how to make the programmer I have work with my Mac laptop.

Anyway, #1 is fixed. #2 and #3 are things I'll work on later (hopefully successfully...). I got #4 done tonight, and this is how I did it.

My Mac doesn't have a serial port. The STK500 programmer I have interfaces to the computer via a serial port. So I need a USB to serial adapter. I bought one from Sparkfun (I believe), and it worked fine on my PC. But no drivers on the disk for my Mac. Also, I couldn't figure out what the thing was, either from markings on the cable or from the driver disk that came with it (I'm sure I *could* have somehow extracted it from the content of the disk, but I didn't do that).

I plugged the USB serial device into my Mac, and using the system profiler, was able to determine that the device was product ID 0x2303 from Prolific Technology Inc. A short google search later had me downloading the mac adapter from this page. After a reboot, the Mac prompted me to set up a new network device. I didn't really know what to enter, so I just hit apply, and closed the window. After that, the device /dev/cu.usbserial showed up.

I installed the AVR Crosspack next. This gives me the whole package of various command line tools to deal with AVR development on the Mac. Using avrdude (and some experimentation), did the following:

sudo avrdude -p m88 -c stk500v2 -P /dev/cu.usbserial -n -v

I ended up with an error about a bad signature, but it worked!

After a quick Google search, I found out that the ATmega88 device has a different signature than the ATmega88P device. I don't know what the difference in the chip is, but I found this bug report, and copied the file attached to it into my avrdude.conf file. After that, the following worked just fine (only difference is in the device name - m88p instead of m88):

sudo avrdude -p m88p -c stk500v2 -P /dev/cu.usbserial -n -v ]]> jmanton http://www.fabhub.net/blog.php?b=8 http://www.fabhub.net/blog.php?b=7 Fri, 06 Aug 2010 22:11:47 GMT Ran across a couple of really neat things from the people over at Dangerous Prototypes (http://dangerousprototypes.com/). The first one is like a... Ran across a couple of really neat things from the people over at Dangerous Prototypes.

The first one is like a Swiss army knife of electronic testing gadgets, the Bus Pirate. It does all kinds of things, including low-speed logic analysis, programming microcontrollers, and more things that I can name here (feature list).



The other one is a high-speed logic analyzer at a bargain-basement price, the Open Workbench Logic Sniffer. It is inexpensive, but provides 32 channels of logic analysis running at up to 70 MHz. It is based on a Xilinx FPGA, plus open source logic analysis software (SUMP). For those that don't know, that's amazing performance, for something that costs less than $50.

]]> jmanton http://www.fabhub.net/blog.php?b=7 http://www.fabhub.net/blog.php?b=6 Thu, 22 Jul 2010 18:02:35 GMT I just got back from volunteering at my local FabLab, hosting a group from the Don Moyer Boys and Girls Club. I've helped out with the last couple of sessions, and I've learned a lot. This is the first group we've taken through the FabLab, and we are figuring things out like the right size for a class, the types of things that the kids can do on their own, vs. needing one-on-one help, etc.

One of the neat things I've seen is that as the kids are finishing up with their "main" project (a robot kit that they assembled and decorated with tools from the lab), they are starting to get ideas about projects they'd like to pursue on their own.

Today, we were doing some basic 2D sign printing on the laser cutter. Basic stuff - download an image off the web, put a border around it that is cut out, add some text, and send it to the Epilog. One of the kids decided he wants to go further than that. He wants to build a cardboard model of the coliseum in Rome. We started with cardboard and some scissors, and he made a prototype, by stacking layers of cardboard on top of each other. When he had a rough idea of how to proceed, we went to the computer. We found a nice overhead picture of the coliseum that allowed him to see what the contours were on the inside, and the shape of the upper level that is only half there. We didn't finish today, but he is really excited to finish next week. ]]> jmanton http://www.fabhub.net/blog.php?b=6