Eureka!

Not knowing a thing about C++, I think I’ve been able to fumble my way through Dave’s code to the point I can replicate his calculations.

On to coding!

Impecible logic

A conversation from bedtime:

  • “Did you ever break a toy when you were a little boy?”
  • Yes, honey, sometimes I did.  And my daddy was pretty good at fixing things, but we didn’t have a robot.
  • “I have an idea!”
  • Oh?  What’s that?
  • “We’ll get a big box and a pulley and a rope and tie one end to your house when you were a little boy and pull on it and put the other end in my house and then you’ll have a robot when you’re a little boy!”

Robotics Work Area

My work area

My robotics work area

I thought people might be interested in seeing what my robot work area looks like. 1  Part of this last weekend was devoted to organizing the contents of the above library card catalog, putting things in appropriate drawers and labeling them. 2

You can’t really tell from the photo, but each of the Three-Dee printing ‘bots is sitting on a separate filament spindle kit.  I’ve got clear MakerBot PLA loaded underneath the Thing-O-Matic (“Flexo”) and black MakerBot ABS loaded under the Cupcake CNC (“Bender”).3 On the surface of the card catalog you can see a pink bracket I printed for my daughter so we can hang a bathroom towel4 at her level.  I’ve got a power strip duct taped down to the back left of the card catalog.  This has made the entire thing the perfect stand-up computing and soldering station.5

The drawer labels are difficult to read from that image – in large part because of my tragically terrible handwriting. 6  In case you’re interested, the highlights are:

  • Two different drawers labeled, “GLOWSTICKS”
  • One drawer labeled, “GLASSES”
  • One drawer labeled and filled with “NOTEBOOKS”7
  • One for “SPEAKER BADGES” of various kinds.  Admittedly, most are just from attending different conferences.  About a third are from when I was speaking at such conferences.
  • One drawer labeled and filled with various kinds of “TAPE”
  • One for “ORIGAMI” with paper and half-completed projects
  • One for “SANDPAPER” of differing grades
  • One drawer for “CABLES” and one for “USB CABLES”

I’m probably using almost 30 drawers, which is only half the front side of this library card catalog.  It’s got 60 such drawers on the front and back. 8 910  This monster occupies what was originally called a “living room.”  Now we just call it our “robot room.”  I was lobbing to change the name to either “The Robotics Lab,” “The Lah-BOHR-Ah-tory,” or the “Laboratory” but the idea did not receive the required 67% of household votes.

The way that I look at it – I could quadruple my robotics hobby and still have enough drawers for it all…

  1. It’s a bit messy, but worlds better than before I tidied it up. [↩]
  2. I had posted a description a while back, but this probably explains it all much better. [↩]
  3. FYI, Flexo has a small magnet installed behind the front panel.  That way I can affix a detachable magnetic soul patch. [↩]
  4. What color do you want, honey?  “Pink, PINK!”  *sigh* Now, if ONLY we had a robot that could make a pink towel hook for you…  “Daddy, stop being silly.  Of course we do!” [↩]
  5. I use a long wooden tray when I solder or assemble something with small fiddly bits.  That way if I drop something it falls into the tray. [↩]
  6. If anything, the JPG compression probably helps the readability. [↩]
  7. Including my DIY homebrew recycled paper and shopping bag analog notebook [↩]
  8. The sad part is this thing is SO huge and SO heavy that if we move, we’ll never be able to take it with us. [↩]
  9. It took an unreal amount of fuel, beer, and pizza to move it to where it is today. [↩]
  10. If you live in the Bay Area and are interested in it – drop me a line. [↩]

Scrapping for parts

Over the weekend I took apart two old DVD players for parts.  I found some interesting small motors, magnets, tiny precision rods, and some other assorted odds and ends.

Today at work our office manager mentioned that some e-waste recyclers were coming out to pick up some old printers and other stuff.  I suggested we pull out any left over paper, toner cartridges, etc from the assemblies.  I would have liked to have scrapped these machines for parts too, but:

  • There’s only so much time in the day.
  • I don’t have any screwdrivers and other assorted tools at work.
  • Hanging out in the middle of the office taking things apart might raise eyebrows. 1

As I did so I realized that the toner cartridges contain thin precision rods.  Those could actually be kinda useful.  I think the next time we have old printer cartridges at home (or work) I might take one apart to see what kind of magic it hides.

  1. “Um, did he forget his meds again?” [↩]

I did it!

I desoldered the burned H bridge on my extruder board and soldered in a new one!!!  I’m so freaking happy!

I’ll be posting the details soon…

Anyone in the Bay Area with a burned out extruder board?

Laptop woes

I probably own about four or five laptops – all in states of serious disrepair.  I have broken down laptops like some people have cars on blocks on their lawn or tires in piles in their backyard.  Here’s what I’ve got right now, with a description of what it would take to fix it:

  • Dell Somethingorother.  Purchased used, old, heavy, running Windows 98, one bad pixel1 , terrible battery life, and about 1/2 the keys on the keyboard do not register unless you literally hurt your fingers pressing/hitting it.  With an external keyboard it’s not that bad, really.  I’ve got a PCMII WiFi card for it.
    • This laptop just isn’t for most people.  If you want to surf the web and word processing, it would be fine with an external keyboard.  That said, it’s pretty slow.
  • Dell XPS.  This is one of the few computers I’ve owned since it was brand new.  Big hard drive, DVD burner, speedy.  However, it’s running Vista (boo!!!), the battery lasts about half an hour, and the monitor is extremely dim no matter what I do.  I leave this one plugged into my Cupcake.
    • Vista is a pain, but an endurable one.  The monitor is dim enough that it is noticeable.  There’s no specific thing keeping me from using this laptop except that it is heavier than what I would like to carry around.  It’s on it’s second battery, an after market special, that holds about an hour or so of charge.
  • Everex Stepnote.  A computer I fixed twice,2 the previous owner drained the battery and let it sit for six months, threw it around, broke off both hinge covers, and scratched it all up to hell.  The DVD drive is completely shot and the battery lasts about 5 minutes.  It’s only got 1 GB of RAM, so it gets bogged down with medium tasks.  Last, but not least, the “+/=” button does not work.  At all.  The lack of those two keys makes programming a bear. 3
    • I’ve been using this laptop almost exclusively for the last year or so.  But, having the +/= button go bad means I am disincentivized to program – which is a bad thing.  I’ve taken this laptop apart, but there’s no way I can see to fix that button short of replacing the keyboard.  At $35+, the replacement keyboard costs on eBay not cost-effective.  The cost to upgrade this computer is not appetizing – $50 for 2GB RAM, $35 for a keyboard, $30 for a new battery?  That’s $115 for an underpowered laptop that is weighed down by a non-functional optical drive.
  • Dell Mini10.  Another twice fixed computer, zero battery (it holds absolutely no charge), tight keyboard, and small screen with a pretty poor resolution.
    • Nothing can be done about the screen, its resolution, or battery.  I could get a new battery, but my concern is there’s some flaw on the motherboard causing it to systematically kill the battery.  When traveling I take this laptop with me and use it to connect into my home network via a VPN.  It would be better with a battery, but with the screen as bad as it is, I’m not looking to spend much time using this computer.  This is the laptop I booted with Ubuntu and wasn’t able to connect to my WiFi network. 4

I’m somewhat undecided on what to do.  Should I get a new computer or try to get one of these running better?

  • Anything over 2-3 hours is great.  Bonus points for more.
  • Minus points for an optical drive – I have an external and don’t need the extra weight.
  • Keyboard and monitor size can be small, as long as it has good resolution.
  • Any current processor is fine, I offload all big tasks (video transcoding, etc) to brainier machines on the home VPN, but 2GB RAM is pretty key
  • Lower price is better, obv.

Anyone have any suggestions?  Either for repairing or what you’d recommend for a laptop?

  1. Stuck on red, if you must know [↩]
  2. Seriously, Tom – who the hell deletes an operating system… TWICE??? [↩]
  3. Amusing note:  in order to circumvent this problem, there is a “+=” contained on every page of this blog – in white text on the white background.  When I need either symbol, I just pull up this site, copy the character I need, paste, and rock on. [↩]
  4. I suspect there was some problem with Ubuntu not recognizing my WiFi card [↩]

DIY laser cutting

Peter Jansen's reciprocating laser concept

Peter Jansen's reciprocating laser concept

Peter Jansen’s latest post about selective laser sintering (SLS) is nothing short of amazing.  Most of his posts on the RepRap Builders blog posts deal with his adventures and research into SLS fabrication – basically directing a laser over a bed of powder to fuse powder in successive layers into a 3D object.  Since the object is being created in a bed of powder and any new layer is supported by the powder above it, the powder print media becomes it’s own support material.

His latest post diverges from his adventures with SLS 3D printing and details his efforts at building a DIY laser cutter.  His idea is for a “reciprocating laser” which would change the focal length or the height of the laser above the material being cut.  Peter points out that commercial high power laser cutters essentially brute force burn through the entire depth of the material to be cut.  They’re so powerful that it doesn’t matter that the laser is out of focus and “cooler” at different depths.

He has demonstrated a proof of concept using much lower power laser to cut material by lowering a much lower power laser as it cuts material.  The downside is that the lower power laser requires a much longer time to burn through the material – having to hit the same area several times at different depths to cut all the way through.  His proof of concept setup was about the size of a CD/DVD drive – since CD/DVD drives, motors, and housing provided most of his building materials.  So far he’s been able to burn through most of two CD case backs – about 2mm together.  He’s hoping to push it to cut thicknesses up to 3.0mm to 4.5mm.

The incredibly small size of his setup means that it can only very small pieces of material.  However, this gave me two ideas:

  1. If the low power lasers are so cheap, why not install multiple lasers at different focal lengths?
  2. If the entire setup is that small, what about making the entire setup mobile? 1  Think hexapod CNC mill.  If a laser cutter wheeled or hexapod robot was as small as a CD drive, you could conceivably just take out a large sheet of acrylic or thin plywood, set the robot in the dead center, and let it go. 2
  1. This reminds me of one of my favorite sayings.  “If Mohammed won’t go to the mountain, the mountain must come to Mohammed.” [↩]
  2. The robot could stay oriented in any number of ways.  You could draw a grid on the material, the material could have a thin paper coating with LeapFrog style micro-dots that told the robot it’s location, you could project a grid onto the material with light or guide it with another laser like a laser guided missile. [↩]

MakerBot woes

Building my MakerBot and getting it printing reliably was challenging, but totally doable by a technical novice such as myself.  I have lots of people on the MakerBot Operators group to thank for their patience and help in getting my MakerBot online. 1  Looking back, I spent about a month building and then calibrating my ‘bot. 2

It’s easy for me to forget that first month of occasional frustrations and triumphant victories, now that I’ve been printing successfully for more than eight months.  It actually makes me a little sad when I read people writing about their own frustrations and how they’re ready to throw in the towel.  The most recent example was noobcake getting frustrated with her ‘bot and getting ready to sell it off in parts.  Thankfully, Spacexula swooped in to help her out.

This brings me to We Alone On Earth‘s recent post.  WAOE are a group of introspective, philosophically and technologically minded twenty-somethings.  To give you you an idea of their frustration with their ‘bot, the post was entitled, “MakerBot: not very much fun at the moment (caveat emptor)”  Yikes. 3  I realize that WAOE has revised their original post several times since the original publishing date – but they have a lot of legitimate concerns.

WAOE list off seven problems with the MakerBot.  I’m not going to refute these points – but rather offer another perspective on them.  After several updates, WAOE offer additional comments, I’ll include them here in “[]“.

  1. The PTFE is prone to melting.  [WAOE expects the new MK5 Plastruder will resolve this issue]. I have never heard of a PTFE barrier melting.  I’ve heard of them deforming from a blockage and had one develop a clog which I had to remove.  Several people have purchased MakerGear PEEK replacements – but these are far from necessary.  I clogged my first barrier once, cleared it, clogged it again, and am now using a slice of it as an insulating washer.
  2. Inexplicable printing behavior due to noise.  [WAOE fixed this issue by twisting wires and installing a resistor]. I’ve never had this problem, but I know others have.  Like WAOE, I’ve heard of people fixing these issues by twisting wires, using resistors, or ferrite beads.  Perhaps my workstation has less electronic noise, but I haven’t had to do any of these things.  Then again, perhaps my prints suffer from a certain degree of noise?
  3. Printing large objects is hard without a heated build plate.  [WAOE notes this isn't an issue if you're good at soldering]. Totally true for ABS, but not PLA.4  However, this is really a problem with the print media – not with the printer, right?  ABS will warp as it cools, unfortunate but true.  I’ve had less warping problems in warm weather or during with a second print – basically when the build platform is already warmed up.  Zaggo’s printruder is one of the largest things I’ve printed.  Interestingly, his design takes into account that certain parts are expected to warp. 5  Or check out Clothbot’s train track – it was designed with a lattice/correlated bottom to prevent warp problems.  Plastic warps – but with careful and thoughtful designing, this shouldn’t be a limitation.
  4. The heated build platform is difficult to build and requires a relay kit. [WAOE notes this isn't an issue if you're good at soldering]. I can’t dispute either point.  I just got both and haven’t had a chance to assemble them yet.  I’m assuming the heated build platform, which requires SMT soldering, will be challenging.  Frankly, fear of SMT soldering was the big reason why I didn’t jump into buying a MakerBot sooner. 6  The MakerBot HBP is just one option for a heated platform – there’s several others out there.  Don’t like SMT soldering?  Try out Rick’s platform over at MakerGear.  More into DIY?  Well, use the plans posted for any of several other variations.  As for the relay kit – it’s not a requirement – but it will prevent MOFSETs from burning out on your extruder motherboard. 7
  5. Calibrating Skeinforge is hard.  [WAOE notes this is still an issue]. I like to use the word, “challenging.”  A better way to look at MakerBot calibration is that you get out of it what you put into it.  I have my MakerBot tuned to the point that I get reasonably good looking durable parts.  Sure, I could spend more time and get even better looking parts.  However, once I got it printing reliably I was much more interested in printing new things than refining the printing process.  I’ll get around to improving the print quality even more – but I’m having too much fun right now.
  6. The Plastruder MK4 feed system is unreliable. [WAOE expects the new MK5 Plastruder will resolve this issue]. Getting the tension on the MK4 idler wheel is just one of those aspects of my MakerBot I had to experiment with and get just right.  I’ve been printing reliably for eight months using the same idler wheel and gear.  With proper maintenance, flossing the extruder, and clearing chips out of the extruder the current setup is serving me well.
  7. The threaded rods are of poor quality. [WAOE are getting new threaded rods, which should fix their problem.]. Of my four threaded rods, one is definitely warped and two have very minor warps.  By experimenting, rotating them just so, and printing a few wobble arrestors I’ve eliminated most of these issues.  You can definitely get more expensive and straighter threaded rods and improve your build quality.

A MakerBot Cupcake CNC kit is not for everyone – but the kit can be build and operated by anyone who is willing to invest the time to do so.  It is a cheap, hackable machine that is literally going to be just as useful as you make it.  Want less warpage, higher resolution, more reliable extrusion?  You can buy an upgrade, build one from their plans, or design your own solution. 8  Want a CNC mill, CNC pencil, or CNC music box?  Design the very first one!  Then again, you don’t have to do any of these things.

A MakerBot kit is just a platform for your creativity.  It’s just that big. 9

As for you, WAOE, if you want some help – drop me a line!

  1. If I had an acceptance speech, I’d go on and on while the music played. [↩]
  2. My first successful print was on 12/31/2009. [↩]
  3. Don’t get me wrong – I love my MakerBot, but I readily acknowledge its limitations. [↩]
  4. From what I heard.  :)  [↩]
  5. It was designed before availability or widespread use of heated build platforms. [↩]
  6. Well, that and a little thing called “money.” [↩]
  7. Did I get that part right? [↩]
  8. I haven’t installed a single non-printed upgrade. [↩]
  9. Or that small.  :)  [↩]