Category: Projects

Various different projects in various states of construction and destruction

DrawBot – Printed Parts

So far I’ve got three types of printed parts:

  1. Spools
    1. These spools hold the monofilament and are friction fit onto the motor shaft.  You can check out the designs on Thingiverse.
  2. Motor Mounts
    1. The Thingiverse page actually has a lot of information about the motor mounts.  They’re designed in OpenSCAD and are mostly parametric.  Since I’m mounting these motors inside a box, the mounts are designed to go into the corners of the box.
  3. John Abella’s Gondola
    1. I haven’t hooked everything up yet, so I don’t know how well this will work.  I can’t wait to find out!
  4. Arduino Mount
    1. I’m kicking around some ideas for how this would work.  Ideally, I’ll end up designing a bracket that the Arduino and motor shield can just snap into.
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DrawBot – The Assembly, Part VI

Okay!  It was a good day for drawing robots in the MakerBlock household!  Here’s what we got accomplished:

  • I designed some motor mounts, printed one… and had to redesign it.  Gotta love having a 3D printer!
  • I selected a long shallow pine box to hold the motors and electronics.
  • I tried a variety of sound insulating materials.  Bubble wrap was easily the most effective, but least practical.  I settled on some corrugated cardboard.  I placed some cardboard between the motor and the motor mount and between the motor mount and the wood.
  • I soldered some longer wires to the motor leads.
  • I drilled holes in the wooden box, attached some monofilament line to the spools, put the spools on the motors, mounted the motors, ran the leads to the Arduino, powered it up… and it moved around and stuff!

As this point the next step is to mount it on the wall and actually attempt to draw stuff.  Yay!

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DrawBot – The Assembly, Part V

I just finished soldering the Adafruit Motor Shield … this time with all the bits in the correct places.  The Adafruit directions are incredibly detailed, I just soldered a few parts in wrong like an idiot last time. This time it went much smoother and much quicker.

I just wired up the two steppers, plugged in the power adapter, plugged in the USB cable, uploaded the Polargraph firmware, fired up the Polargraph software, and asked it to try to draw something.  And it started to twitch away in what appeared to be a meaningful pattern!!!

Huzzah!

Now… for sleep!

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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

    [↩]

  2. I’ll want to make sure I can get this first one sorted before I try [↩]
  3. 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 [↩]
  4. Gah, why didn’t I pick up a desoldering pump while I was out today?! [↩]
  5. And chipped, at that. [↩]
  6. It’s really quite a miracle I got the first board soldered at all in the first place. [↩]

DrawBot – The Silver Lining of Failure

After having fried my Adafruit motor shield with excessive levels of stupidity by accidentally soldering two chips in each other’s spots, I thought of a little bit of silver lining.  I now have an H-bridge and an IC that may both still be good!

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DrawBot – The Face Palm

Okay.  Confession time.

First, if you have been following along at home, I’m sorry – I have been leading you on a fool’s quest.  I did warn you at the outset I had no idea what the hell I was doing.  Carry on, don’t worry about me, I’ll go down with this ship.

Second, here’s the actual confession.  Despite amazingly detailed directions from Adafruit’s website, I soldered the Adafruit Motor/Stepper/Servo Shield for Arduino Kit v1.0 totally totally wrong.  I soldered one of the L293D chips into the location for the 74HC595N integrated circuit chip.  And I wondered why it didn’t work.

This would completely explain why the shield made a pop noise, why there was the smell of burning, and why one of the L293D chips (which was not an L293D chip AT ALL) was getting super hot while the other was just fine.  I just tried to de-solder the L293D chip, but that’s not going to work.  I’ve de-soldered a part before, but surface mount parts are MUCH easier to de-solder. 1

At this point my choices are, from wisest to most foolish:

  1. Abandon all hope and prayer of building a DrawBot.  Power down my laptop, unplug my router, take the battery out of my phone and stop inflicting my delirium on the world.
  2. Order another Adafruit Motor/Stepper/Servo Shield for Arduino Kit v1.0, and start again. 2
  3. Keep trying to de-solder that damned L293D chip, hope and pray I didn’t destroy both the L293D and the 74HC595N, then try to put them in their proper spots.
  4. Damn the torpedoes!  Full speed ahead!  Who cares that one sad little chip refuses to act like another sad little chip?!  More power and brute force will carry the day.  If I cannot make this work, I will ride this project straight into HELL!  Mu-ah-ha-ha!!!3

I’ve taken a stab at desoldering the L293D, but it just isn’t working.  The solder isn’t really coming out.  Even if it does, I’m going to have one hellishly ugly board by the end of the day – and I’ve probably already burned out the L293D and/or the 74HC595N.

At this point, I think I’ll opt for #2 above.

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  1. Score one for SMT, eh? [↩]
  2. It’s a nice day to start again. [↩]
  3. The world is ours, let’s use it up. [↩]

DrawBot – Halp!!! No – seriously, a little help?

Okay, I’m stuck.  I don’ t know what I’m doing wrong or what I need to do next.  So, I’m calling upon John Abella, Sandy Noble, and Kongorilla for your help.  :)

Here’s where I am:

  • The burning!
    • At last attempt, I hooked up some small steppers to the Adafruit motor shield, put the shield on my Arduino Uno, hooked up the USB cable and the 9v power adapter.
    • I heard a small pop and smelled warm electronics.1
  • After the burning
    • I can upload and run the Arduino basic blink sketch.  I can alter this to change the blinking pattern.
    • I can upload and run the Arduino sketches to operate a microservo.  I can alter this to change the microservo’s behavior.
    • I can upload the Adafruit sketches for steppers – but I can’t make the steppers move.
    • I can upload the Polargraph sketch – but I can’t make the steppers do anything.

Now, I’ve got tons of questions for you:

  1. Did I ruin my Arduino?  I can still run the blink and microservo sketches.
  2. Did I ruin my motor shield?  How can I tell if it is operational?  When I connect the power to the Arduino and have the little jumper in place, the green LED is lit up.
  3. What am I doing wrong?
  4. What should I try next?
  5. How should I diagnose a problem?
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  1. Now I’ve got a cold and couldn’t smell anything if I wanted [↩]

DrawBot – Design Considerations

This post isn’t really so much of an update as it is a way for me to jot down some thoughts about this DrawBot and to keep me occupied. 1 23

  1. Stepper motors mounts
    1. Right now I’m designing some rather mundane stepper motor mounts.  They’re inspired by Ed’s designs, but I’ve written the code myself.  I’ll post the code on Thingiverse once I’ve printed it.  It will output a good looking motor mount, but the design isn’t entirely parametric yet.
  2. Beaded cord, belts, and filament, oh my!
    1. If you check out this Polargraph video, you can see @ 0:22 where Sandy Noble shows a version of his Polargraph operating using two spools winding and unwinding filament.  The versions Sandy was producing for sale used a beaded cord.  The Der Kritzler uses a toothed belt.
    2. There are several downsides to using beaded cord4 or toothed belts.  First, they’re more expensive and slightly more work to obtain than simple mono filament line.  Secondly, they are both bulky.  If you’re using beaded cord or a toothed belt, they’re going to have to dangle off the side of your machine.  This means more moving and swinging parts – which is a whole other problem.
    3. One of the benefits to using a filament line is that you can easily route and redirect the line using pulleys.  This means that you could mount the motors and electronics in close proximity to each other – and then run the filament line through something like an eye bolt or a specially designed5 part.
    4. I don’t know how any of these options would affect the placement and usage of a servo for penlifts.
  3. In a box6
    1. I have this long shallow pine box, at least three feet in length, that may be perfect for this project.  I think I’ll be able to mount the motors, electronics, and just about everything I need entirely inside this box.  If I do, then all I’ll need to do later is mount the box to the wall, plug the USB cable into a computer, plus the power adapter into the wall, and start printing away!  Now, I realize that this implies a totally vertical drawing surface, but I think that is not as much of a problem as it could be.
  4. The Russians used a pencil
    1. Writing on a perfectly vertical surface with a pen can be challenging.  My thought is to create a gondola that has the weight farther back on the gondola – so that it is pushing the pen against the paper.  If the pen were angled down slightly, this might even work a little better.   But, obviously, I’ve never tried any of these variations.  I have to imagine that smarter men than me have considered and discarded these designs.  I have a crappy sketch for this, but I’m really tired and should get some sleep.

To sleep, perchance to dream.  Ay, there’s the rub.

Fear not gentle reader.  If history tells us anything, tomorrow shall bring your RSS feed another deluge of nonsense!

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  1. I don’t feel like working, even though the hour grows late and I will need to get a bunch of things done one way or another. [↩]
  2. And, really making a drawing robot is SO much more productive than what I do on a daily basis. [↩]
  3. I wish I were kidding. [↩]
  4. Either metal or plastic [↩]
  5. Perhaps printed?! [↩]
  6. With a fox! [↩]

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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Test