DrawBot – The Assembly, Part VIII

Well, my newly designed motor mounts, while cool, just aren’t working.  If I were committed to using that long pine box, I could probably make a go of them.  I’ve tried several variations on this robot, and nothing has really worked so far.  Here’s what I’ve tried:

  1. In a box, mounted to the wall
    1. This just didn’t work.  The spot I found on the wall was in our robot room, behind my monstrous card catalog.  It was difficult to get to, the laptop I had it hooked up to wasn’t really talking to the robot, and I didn’t even get it fully hooked up in that location before I decided it just wasn’t going to work.
  2. In a box, under an easel
    1. In a fit of inspiration I realized that I had a painting easel, a rather nice one at that.  I took an old new canvas1 , put it on the easel, put the easel’s feet inside the long pine box, ran the monofilament line from the motor, through holes in the pine box, up behind the canvas, through an eyescrew on top of the canvas, and down over the front.  This was terrible.  It creaked, shuddered, and the pen sputtered around the front.
  3. In a box, on an easel
    1. Not ready to give up on Project Easel, I tried to put the pine box on top of the canvas and hold them together in the easel.  This really didn’t work.  Because of the location of the motors in the pine box, the canvas was either going to block the holes for the monofilament line or I’d have to run the line through the top of the box, which would have resulted in the same creaky, shuddering, sputtering problem of using the line through a hole in the box as if it were a pulley.  Either way, the entire assembly just wasn’t stable on the easel which did not want to hold it together.
  4. Bolted to a chunk of wood
    1. I actually have some spare plywood, but it’s been in the garage for a while and has a weathered look to it.  It also has a large 1.5 foot radius quarter circle cut out of it.  I figure if I’m going to keep this inside, I might as well spring for a new piece of wood.  A bit over $14 at the hardware store and I was in business.  Now that I’ve given up on my nifty motor mounts, I designed and printed a dead simple motor mount.  I could have accomplished much the same result by just drilling some holes in a piece of scrap wood. 2  I’ve also abandoned a gondola of my own design. 3
    2. The final result is essentially as follows – a 2’x4’x0.5″ piece of plywood, wrapped in butcher paper, two steppers bolted to mounts and screwed to the left and right sides at the end of the plywood.  The steppers are wired to the stepper motor in the center, and the Arduino and stepper motor controller are in an ill-fitting plastic holder which is duct taped to the front top of the plywood.  The plywood is then propped up against our built-in on which my most useless laptop is sitting, ready to run the robot.
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  1. Old because I’ve had it for about 10 years; new because it’s still in the shrink wrap.  Now, to my credit, I have actually painted on my other canvases – this is just the last one and I completely forgot about it. []
  2. These will probably have been the very very last thing I’ll have ever printed with my black ABS. []
  3. While cool, it just did not work well at all – I made the pen holder so large it would only hold the largest sharpie made by man, it didn’t do a good job of holding the pen against the paper, and it held the weights rather awkwardly. []

DrawBot – The Assembly, Part VII

Yesterday I accomplished a little more with my DrawBot.  Here’s what I did:

  1. Drilled holes in my project box1 for running mounting wires through the box.
  2. Drilled holes in my project box for the power cord and USB cable.
  3. I added several yards of monofilament line to each spool.  The way I have the motors mounted into the box I had to add some filament line to it on the spool.  Obviously, I had no way of knowing how much line I would need, so I just added a few feet.  Today I cut off several additional yards, tied the new section to the shorter section already attached to the spool2 , cut off the little loose ends, and rolled the spool with a finger.
  4. Found studs in the wall, put two huge screws into two studs3 for holding the box on the wall.
  5. Ran some sturdy steel wire through the box for mounting on the wall.
  6. Cut a huge sheet of cardboard out of a box we had in the garage.  I wrapped three edges of it in packing tape, so that it would remain flat and not shed little bits of cardboard paper.  The fourth edge I covered with duct tape for a sturdier hold.  This was then mounted on the wall underneath the pine box using more huge screws going through the side with the duct tape.  The purpose of this is to give the DrawBot a flat surface to draw on, rather than the textured wall.
  7. I then plugged the power cable and USB cables in and tried to fire up the Polargraph software.  Since this is all being done in a different room, I’m connecting all of this to a totally different laptop using different software.  I have an older laptop running Windows Vista that is connected to my Thing-O-Matic and Cupcake.  Now it is attached to my DrawBot as well.
  8. At this point the only physical components of the DrawBot missing are the gondola which I haven’t installed and blank paper.
  9. Unfortunately, that laptop I connected the DrawBot to is having some kind of problem communicating with the Arduino.  But, that’s another problem for another day.
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  1. A long pine box []
  2. Square knot []
  3. True story:  My wife heard the new electronic stud finder going all wacky from the family room.  She called back, “If it’s making that beeping noise, you’re doing something wrong.”  I replied, “Yeah, I’m just running it over my belly just to see what it will do.”  My daughter ran over in disbelief and then called back to my wife, “Mom!  Daddy’s rubbing the finder on his tummy!”  Say what you will, that damn thing is accurate. []

DrawBot – The Delivery, Part VI

Okay, that was FAST.  I ordered the Adafruit motor shield from MakerBot on 1/26/2012 just after midnight and it arrived today a little after noon.  That’s about two-and-a-half days for the parts to be packed, shipped, make it from Brooklyn, NY to Oakland, CA and then to my secret robot lair in the Bay Area.1  While at the hardware store today I picked up some small eyescrews and new tips for my soldering iron.  Tonight I’ll assemble the board.  Again.

I can honestly say that I was mightily tempted to purchase a third motor shield along with this second.  However, as I have no immediate designs on a secondary DrawBot2 I’m not ready to admit the possibility of defeat.  In the words of Kongorilla, I will not fail.3

Actually, now that I’ve got these new soldering iron tips, I stand a chance of being able to desolder the mis-soldered parts. 4 My old soldering tips were old, tarnished, and somewhat crusty.  The soldering tip I’m replacing is all of these things plus it is in the rough shape of a flathead screwdriver. 56

Wish me luck!

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    • Delivered, January 28, 2012, 12:09 pm, [SECRET ROBOT LAIR], CA [9XXXX]
    • Out for Delivery, January 28, 2012, 8:14 am, [SECRET ROBOT LAIR], CA [9XXXX]
    • Sorting Complete, January 28, 2012, 8:04 am, [SECRET ROBOT LAIR], CA [9XXXX]
    • Arrival at Post Office, January 28, 2012, 5:17 am, [SECRET ROBOT LAIR], CA [9XXXX]
    • Depart USPS Sort Facility, January 28, 2012, OAKLAND, CA 94615
    • Processed through USPS Sort Facility, January 28, 2012, 2:26 am, OAKLAND, CA 94615
    • Electronic Shipping Info Received, January 27, 2012
    • Depart USPS Sort Facility, January 27, 2012, BETHPAGE, NY 11714
    • Processed at USPS Origin Sort Facility, January 26, 2012, 11:40 pm, BETHPAGE, NY 11714
    • Accepted at USPS Origin Sort Facility, January 26, 2012, 10:25 pm, BROOKLYN, NY 11217

    []

  1. I’ll want to make sure I can get this first one sorted before I try []
  2. Actually, that’s a little more bravado than I’m really capable of.  If I fail, I fail – I just have no intention of ending at failure.  Rather, I’m committing to repeated failures … until I end up with a working DrawBot []
  3. Gah, why didn’t I pick up a desoldering pump while I was out today?! []
  4. And chipped, at that. []
  5. It’s really quite a miracle I got the first board soldered at all in the first place. []

DrawBot – The Assembly, Part IV

Here’s what I was able to do last night:

  • As I’ve mentioned, I know very very little about Arduinos or how to hook them up.  Although the Adafruit stepper motor page gives some guidance as to how to hook up the Stepper motor – 200 steps/rev, 12V 350mA, “Red, Yellow, skip ground, Green, Brown,” I have no idea which side or starting from which end of the terminal block this is supposed to go.  Admittedly, I have a 50/50 chance of wiring it up properly.
  • I tried hooking up two old steppers I had scrapped from some old electronics – but all I got for my troubles was a small popping noise and the smell of electronics.  There was no blue smoke, no apparently burned parts, and I was able to program the Arduino Uno to blink and then run a servo through the Motor Shield.
  • I designed and printed a spool for holding the monofilament line and which will fit snugly on the stepper motor shaft.  I got a little sidetracked playing with Skeinforge settings, but the spools turned out really well.
  • I printed a gondola for holding the pen, designed for the Polargraph by John Abella
  • I designed and printed a holder for the Arduino with the Motor Shield on it – but it was slightly too narrow for some reason.  I’ll have to redesign, reprint.
  • I’ll have to design and print a new motor block as well as a filament line guide.  I have some cool ideas for the latter.
  • I tried to use the Polargraph controller, but I wasn’t able to get it to do much.  I”ll give it another whirl tonight.
  • I know I’ll also have to change some of the Polargraph Arduino code to accommodate the motor and spool combination I’m using.
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DrawBot – The Assembly, Part III

I debated with myself over how best to lay out my build log for this DrawBot. 1  Is it better to post the build process as I’m working on it, so that it would span numerous posts, or is it better to try to keep posting all the major steps into one post so that it is easy to follow?  At the cost of appearing repeatedly repetitious over and over again, I think if I were following along at home I’d want to read either one long post that covers everything or a small series of posts that cover the few major steps.  It’s easier at this stage to put all the information into one long post, revising it as I go along and pruning the ubiquitous2 nonsense out as I go.

Here’s what I’m adding in this iteration:3

  1. A section about optional hacks to the Adafruit Motor Shield
  2. More detail about the various libraries and the sketch necessary to upload the Polargraph source code
  3. Instructions for uploading the Polargraph source code
  4. Slightly better organization of my build outline

Continue reading

  1. FYI, I was explaining this DrawBot to a friend at a party yesterday.  He suggested I create a wipe board robot instead, similar to the Lady Ada and Matt Metts robots, and call it the BotWiper. []
  2. Don’t you just love that word? []
  3. Since this information is 95% stuff you would have seen from the prior Assembly post, I’ll put it after a little “More” tag. []

DrawBot – The Assembly, Part I

I assembled most of the Adafruit Motor/Stepper/Servo Shield for Arduino kit – v1.0 last night.  Since I don’t have an Arduino yet,1 I didn’t want to solder in the connector pins.  Other than those four connectors, it is all soldered up.

FYI, don’t try to put the L293D into the 16-pin sockets before you solder the socket into place.  I tried to do that and it was a mistake.  I bent some of the leads to the socket and stabbed myself in the finger with the L293D chip.

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  1. It’s on its way!!! []

DrawBot – The Delivery, Part III

So, I’ve figured it out.  Admittedly, it took until about 4:45pm today, but I figured it out.

Today was Friday the Thirteenth.  Duh.  That DEFINITELY explains my work day.

I was very happy to find the Adafruit Motor/Stepper/Servo Shield for Arduino kit – v1.0 had arrived from MakerBot.  When I opened1 the package I noticed that the kit really was a kit.  Which I already knew.  I knew this was a kit, but somehow I kinda forgot about it.

In a way, it’s irrelevant that I don’t have the other parts since I have to assemble this kit.  So, tonight I’ll assemble the motor shield and tomorrow, hopefully, I can assemble the rest of the DrawBot.

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  1. Read: shredded the USPS box []

PLA Woes

My adventure with PLA has ended in heartbreak.  It wasn’t working very well so I switched back to ABS – which was fine for a few prints.  Until I found it just wasn’t extruding and stripping the filament.

So, disassemble time.  My filament looked like it was getting shoved into a jam and splitting apart like a banana – with the center making it down to the nozzle through a small aperture.  I found I couldn’t remove the insulator – and upon looking closer found that a very small amount of PLA had oozed down and around the nut above the insulator/ washer.  I removed the extruder assembly from the ‘bot, and the heater assembly from the extruder, heated it back up and slowly removed the PTFE insulator.  I found the barrel was clogged with ABS as was the insulator.

I’ve managed to clean out most of the insulator, the nut, and the threads of the barrel using drill bits and precision screwdrivers.

I’m going back to ABS, I would rather deal with warp than the heartbreak of PLA ooze into the threads of my heater assembly.

Heater barrel – backasswards?

Dangit.  According to the very latest changes to the MakerBot assembly wiki, I put the heater assembly together with the heater barrel upside down.  I’m not entirely sure what this means for my heater.  Clearly it was working well enough that I could extrude reasonably well.

The questions is – do I leave it as is or disassemble/reassemble?

If I leave it as is, I suppose there’s a chance I could bulge the insulator, ruining it.

I’ve already disassembled/reassembled once because of a bad thermistor connection.  If I disassemble again, I’m thinking the ceramic tape and nichrome may have had it.  Not to mention that I’m probably going to have a royal mess of plastic inside the barrel and nozzle to clean up.