Monthly Archives: August 2014

ClearNav Joystick Part 4 – Back to the Drawing Board Again

Part 3 described a ‘back to the drawing board’ approach to the ClearNav remote caddy joystick grip project. That effort resulted in a cylindrical grip with the CN caddy from the clay model grafted on.  This worked out OK, but it didn’t look very pretty – it was a bit asymmetric, and I never got the surface smoothness I wanted on the caddy section – it was kind of lumpy and irregular.

So, I went back into MeshMixer and spent some quality time figuring out how to use the sculpting tools more effectively.  The documentation for all of the Autodesk 123 products (and TinkerCad too) is almost non-existent, so the only way I have found to learn how to use the various tools is by trolling for the few (and also now outdated) YouTube videos and by brute-force experimentation.  Anyway, after many hours of playing around, I figured out how to do such things as combining MeshMixer-provided primitive shapes with my clay model derived CN caddy section, and how to use the ‘attract’ sculpting tool to regularize surfaces – very neat!!  I was ultimately able to combine both a rectilinear solid and a torus into something that was a lot more regular, and may well have formed the basis for a successful CN remote caddy grip.  However, as I was doing all this (and learning a LOT), it occurred to me that I was once again going about this the hard way….


It finally occurred to me that if all I wanted was a minimal CN remote caddy, I already had one!  Early on in the project I constructed a blank plug using TinkerCad and working off the dimensions from an old CN remote I had laying around the house.  All I had to do to create a ‘minimalist’ caddy would be to expand this plug a few mm in all directions, and then put a plug-sized hole in the middle of it.

CN Remote plug constructed early on in the project

CN Remote plug constructed early on in the project

So, I copy/pasted the above plug into a new TinkerCad design, expanded it as described above, and mated the result with the cylinder grip from Part 3, as shown below.


Minimal CN remote grip with caddy cavity and CN remote shown

Minimal CN remote grip with caddy cavity and CN remote shown.  Note the cable management loop about halfway down the grip cylinder

Top view showing CN remote installed on minimal grip

Top view showing CN remote installed on minimal grip.  Note the cable management loop about halfway down the grip cylinder

Side view showing CN remote installed

Side view showing CN remote installed.  Note the two cable management loops built into the design.

Side view showing CN remote cable and cable management loops

Side view showing CN remote cable and cable management loops

On all the previous designs, the plan was to utilize the ClearNav stick-top remote accessory rather than the fob-mounted style, as the fob style has a telephone-style connector on the front to connect the cable that goes from the remote to the ClearNav itself.  On this ‘minimalist’ design it occurred to me that I could do away with that requirement by putting a slot in the front of the caddy section to accept the phone jack, and adding a couple of cable management loops to the grip body.  In this way the user could simply detach the remote from the fob and press it into the caddy cavity, and presto – instant stick-top remote!

A complication with this plan is that the CN stick-top remote accessory comes equipped with an integrated PTT switch, as the stick top remote assembly typically takes over the real estate formerly used by the original PTT button.  Since the ‘minimalist’ design doesn’t do that, the user can simply re-use the original PTT button. To facilitate this, I put a small pilot hole in the top center of the cylinder.  I used a pilot hole here because I don’t know the diameter of the original switch.

Anyhoo, this design was shipped off to my friend yesterday, for its date with reality.  I have high hopes for this one, but who knows?  Stay tuned! 😉



ClearNav Joystick Part 3 – Back to the Drawing Board

At the conclusion of Part 2, I had a finished design and a finished 3D part, which I sent off to my friend for evaluation in his glider.  Unfortunately, the evaluation was – “It sticks up too high, and hits my stalk-mounted ClearNav unit”  After going through some back-and-forth, he sent me some photos to illustrate the problem.  The original rubber stick grip with top-mounted PTT switch just clears the bottom of the ClearNav (CN) unit, so anything higher than the original is going to be a problem.  The finished grip I created based on the clay model was, unfortunately, about 2″ too high :-(.

So, back to the drawing board.  I tried a ‘shorty’ version of the original grip, but that only got me about 1″ of the needed 2″ or so height reduction, so that was out.  Then I decided to throw the entire clay model derived design out the window, except for just the CN remote caddy portion, and start over from there.  The problem with the original clay model design was that it was slanted in such a way that it could not slip all the way down onto the stick, so I decided to start with a simply cylindrical grip that would slide completely down onto the stick, and then somehow tack the CN remote caddy onto the front.

Cockpit photos showed that the vertical portion of the joystick was about 4″ long, including the trim release trigger, so I started with a cylinder of a little over 100mm.  This cylinder would house the hole for the stick, so it would obviously have to be bigger than the stick diameter of 25mm, plus some additional wall thickness.  How much bigger?  I decided make it just big enough to completely sever the CN remote caddy portion from the rest of the ‘finished’ grip derived from the clay model.  I started this process in TinkerCad by placing a cylindrical ‘hole’ in the model, and increasing its diameter until it just stuck out of both sides of the model at the neck, separating the front and back halves.  This required a cylinder diameter of 35mm, as shown below.

Separating the CN remote caddy from the rest of the grip

Separating the CN remote caddy from the rest of the grip

Removing the rest of the grip from the design

Removing the rest of the grip from the design

After that, I added a rectangular ‘hole’ to remove the now-separated back half of the grip, leaving only the CN remote caddy portion with a 35mm-diameter arc in the back.  Then I simply added a 35mm diameter solid cylinder to the design in the same place as the ‘hole’, and of course this cylinder fit perfectly into the arc made earlier by the 35mm diameter ‘hole’.  The only thing left to do was to ‘drill’ a 25mm hole into this grip cylinder, leaving a 5mm wall on the sides, and a 3mm wall at the top.  Assuming this grip arrangement was seated fully on the stick, then it should stick up no more than 3mm from the top of the stick itself, or less than the height of the original grip plus PTT switch.

This design is nowhere near as elegant as the clay model derived one, but it should work as a practical starting point for a design that actually works – the elegance can come later!

As a side note on all of this, the process of going from the original design to the ‘cylindrical grip’ design was very interesting because it is completely and utterly different than normal design practices.  Instead of building another design up from scratch, I was able to add just two ‘holes’ and one hollow cylinder to the original design to come up with something completely different.  In TinkerCad, you can add and combine solid parts, but you can also remove material by adding ‘holes’.  Every primitive in TinkerCad can be used as either a solid object that adds material to the design, or as a ‘hole’ that removes material from the design.  Moreover, portions of a design removed by holes don’t get removed until grouped with that hole.  Material that is removed via the addition of a hole isn’t really deleted – it is just ‘hidden’ by whatever combination of holes negates its presence (exporting the design as an STL file and then re-importing it into TinkerCad does, in fact, permanently remove all ‘holed’ portions of the design).  This process leads to some bizarre and counter-intuitive results, as it the order in which holes and solids are grouped determines the final visible result.  In a complex design, it is quite possible to wind up with an unexpected result, because the grouping order got changed somewhere along the way.  If the grouping error occurs down inside the design, then it might not get noticed until the 3D part is printed, and a hole that was supposed to be there isn’t, or some material that wasn’t supposed to be there suddenly reappears!

OK, so this design will go off to my friend tomorrow for yet another clash with reality.  Hopefully this one will be a little closer to usable, and maybe point the way toward a final product – we’ll see!




Dewalt Cordless Drill Bit Holder

I have a really nice DeWalt DCD710 3/8″ cordless drill/driver, and I think it’s the greatest thing since sliced bread.  It’s small, light, very powerful, and the lithium Ion batteries last forever and charge quickly.  What more could a guy ask for, anyway?

DeWalt Cordless Drill/Driver

Well, what I could ask for, but didn’t get, is a convenient way to carry extra (or any, for that matter) driver bits with the cordless drill.  My previous drill had a nice bit caddy built onto the case, and this was a very nice feature.  I tried gluing a metal clip onto the side of the DeWalt, but that lasted only a day or so before it broke off again, leaving only an ugly scar.  So, now that I have my own 3D printing factory, I thought I’d give this another whirl.

The first step was to find a shape that would fit snugly over the top of the drill body, out of the way of normal use.  I started with a circular ring with a rectangular cross-section, and adjusted the diameter and thickness to get what I wanted.  Initially I kept the width small to cut down on printing time

First try at the body clip ring - way too loose!

First try at the body clip ring

After three more tries, I got a body clip that I liked, complete with a prototype bit clips attached.  The bit clips were actually the body clip scaled down, rotated, and translated to attach the sides.  Unfortunately, the details in the body clip didn’t scale well down to the bit clip size, so I basically had to start from a fresh sheet of virtual paper for the bit clip.

TinkerCad drawing for the final body clip, with prototype bit clips attached

TinkerCad drawing for the final body clip, with prototype bit clips attached

Again it took 3/4 revs to get the bit clip geometry the way I wanted it – with a good, firm grip on the bit, but not so ‘firm’ that it would be impossible to get the bit out of the clip without a broken fingernail or two.

Final bit clip detail.  Note the beveled edges (done with a wedge and a rectangle hole

Final bit clip detail. Note the beveled edges (done with a wedge and a rectangle hole

Now to combine the body clip and the bit clip into a final product.  Rather than attach the bit clip to the outer surface of the body clip as I did with the prototype, I had the brilliant idea that I could create an outrigger from the body clip that went forward along the drill body, and then attach the clip to the outrigger.  This would get the stored bits closer to the drill body, and hopefully make them less prone to being pulled off or snagging.


Final body/bit clip fixture. The clip was copy/pasted into the overall design

Final body/bit clip fixture. The clip was copy/pasted into the overall design


ClearNav Joystick Part 2 – From TinkerCad to Finished Print

At the conclusion of ‘Part 1 – From Clay Model to TinkerCad’, I had finally managed to get a decent 3D model into TinkerCad as a binary STL file.  Now the challenge would be to transform that blank template into something that could actually be printed on my PrintrBot and used in a real glider aircraft.  To get from where I was to where I wanted to go required the following steps:


  • Modify the joystick top to accept a ClearNav remote controller
  • Design in the the ability to install a separate switch, for use either as a ‘climb/cruise’ vario switch or as a separate ‘push-to-talk’ (PTT) switch (the ClearNav stick-top remote controller accessory has it’s own integral PTT switch, but…).
  • Create a 1″ diameter hole to mount the joystick onto the glider joystick handle/tube
  • Create a wiring passageway up to the top of the joystick
  • Print it out on my PrintrBot Simple Metal.


Modify the top to accept a ClearNav remote controller

This step appeared to be the hardest and most critical part of the design, so I decided to tackle it first.

Of course, a fundamental part of this step required that I have precise dimensions for the ClearNav stick-top remote controller, and this turned out to be rather more problematic than I had expected.  ClearNav, Inc didn’t have any technical specifications for the part on its website, and the support crew there couldn’t provide anything either.  The president of the company promised to send me a 3D design of a blank controller part as an STL file, but never delivered anything, even after multiple inquiries.  Fortunately, I had a hand-held remote controller left over from my previous life as a glider pilot, and I happened to know that the outside dimensions of the stick-top and hand-held controllers were identical.  The difference was that the stick-top remote has an extra button to replace the normal PTT button, and the hand-held controller does not.  Another non-relevant difference is that the hand-held remote has a telephone-style RJ-45 connector, while the stick-top version uses a wire pigtail.

So, I was able to use my hand-held controller to produce a blank 3D model for sizing the stick-top cavity.  I started out with a blank that was as precise as I could make it, and then oversized it by about 1mm in all dimensions to use as a ‘hole’ in the design.

Disassembled Hand-held ClearNav Remote

Disassembled Hand-held ClearNav Remote

Slightly oversized blank for joystick ClearNav remote cavity

Slightly oversized blank for joystick ClearNav remote cavity

Then I started trying to fit the blank into the top of the joystick, with very limited success initially.

First attempt at fitting the ClearNav remote into the top of the joystick

First attempt at fitting the ClearNav remote into the top of the joystick

The thickness of the 3D representation of the clay model just wasn’t sufficient to contain the volume of the ClearNav remote, no matter how I moved it around.  So, back to the drawing board (literally!).

I did some more research, and taught myself how to use MeshMixer’s ‘Inflate’ sculpting brush to add some bulk to the top of the joystick, and the ‘Flatten’ brush to slim and smooth the neck area.  After several back-and-forths between MeshMixer and TinkerCad, I arrived at a version that would indeed contain the remote.

Close, but no cigar!

Close, but no cigar!

Remote is completely contained now in the joystick, so this one is very close to final

Remote is completely contained now in the joystick.  Note the neck has been slimmed down as well

Design in the the ability to install a separate switch.

The typical cross-country glider uses a boom microphone and a stick-mounted push-to-talk (PTT) switch for radio communications, and there is often at least one more switch (typically a SPDT toggle) mounted on the forward surface of the stick top.  The stick-top ClearNav takes over the real estate used by the original PTT pushbutton, but cleverly replaces it with an integrated PTT switch on the remote itself (this integrated PTT button isn’t on the handheld version).  However, I still needed to make room for the front-mounted SPDT switch.

The first step in this portion of the design was to create a 3D model of a ‘subminiature’ SPDT switch.  Fortunately I happened to have one in my design shop, left over from an even earlier lifetime as an electrical design engineer.  Now that I have my high-quality Fowler calipers from McMaster-Carr, it was a snap to measure the switch and create a fairly accurate 3D model in TinkerCad.

Subminiature SPDT switch model

Subminiature SPDT switch model

Once I had the switch, I was able to figure out how to shoehorn it into the top of the joystick, in a forward-facing orientation.  This took a while, and involved creating a smaller ‘sub-basement’ cavity under the one created to accommodate the ClearNav remote.

MountedSPDTSwitch2 MountedSPDTSwitch1

Create the 1″ diameter mounting hole and wiring passages

You’d think this would be the simple part – just a couple of cylindrical ‘holes’ added to the part and we’re done.  Unfortunately, life (or joystick design) just ain’t that simple, and what I thought would be a ’10 minutes tops’ job turned into a multi-day headache, and finally into a fun piece of creative work.  The initial 1″ diameter hole wasn’t too bad, but since the joystick body isn’t particularly symmetric, it wasn’t (and still isn’t really) clear where the hole should go.  I finally opted for the placement that would allow the hole to penetrate the farthest up into the joystick body, as that would result in the widest range of mounting options in the actual aircraft.  Then I created a smaller diameter angled cylinder to connect the vertical hole to the top cavity, to act as passage for the necessary wiring.

This seemed to be working really well, until I printed a couple of half-scale models and discovered that both the vertical and slanted cylinders poked through the side of the joystick, even thought the TinkerCad model showed some material thickness all the way around.  I was trying (and failing) to figure out how this could possibly happen when my wife, who knows nothing about 3D printing, pointed out that the minimum printable wall thickness stays the same regardless of scale, so something that shows 2-3 min thickness walls at full scale might not be even one min wall thickness at half-scale – oops!

OK, back to the drawing board.  I played around with this forever, but finally concluded that I was going to have to give up on the linear passageway idea, and go with something curved if I wanted to have decent wall thickness all the way around the passageway for its entire length from the top of the 1″ mounting hole to the cavity at the top of the joystick.  To make this work, I used TinkerCad’s ‘Torus’ primitive, and adjusted the torus diameter and cross-section to get what I wanted.  When everything looked right, I used several rectangular ‘holes’ to cut off the sections I didn’t need.

Final version, showing the 1" vertical cylinder for joystick handle mounting, and the curved wiring passageway

Final version, showing the 1″ vertical cylinder for joystick handle mounting, and the curved wiring passageway

Printing on my PrintrBot Simple Metal

After verifying this hole structure via a half-scale model, I was ready to step up to full scale testing.  However, I really really did not want to pay the time and filament cost for multiple full scale prints, so I decided I would just print the top of the model to verify all the cavities at full scale.  Since none of the hole structures poked though anymore at half scale, I was pretty confident they wouldn’t at full scale.  So, I made a series of full scale prints of just the top portion, and these caused me to make some adjustments in the auxiliary SPDT switch cavity and mounting arrangements.  With these partial full scale prints, I was able to use the actual full scale real-world parts (ClearNav remote and subminiature SPDT switch) to check for fit and clearances.

First full scale print of just the top cavity structure.  Note the top part of the cavity is incorrect.

First full scale print of just the top cavity structure. Note the top part of the cavity is incorrect.

Second full scale print of the top cavity structure.  Note the top portion of the cavity has been corrected.

Second full scale print of the top cavity structure. Note the top portion of the cavity has been corrected.

Final version of the joystick top cavity structure

Final version of the joystick top cavity structure.  This just required a slight resizing of the cavity to accommodate the actual full scale ClearNav remote, and the actual full scale SPDT switch.

After the full scale partial printouts, I was ready to go for a full scale print.  The overall height of the joystick (121.6 mm or 4.8″) would be close to the 6″ maximum for my PrintrBot, so I was a bit worried that bad things were going to happen.  Also, since this was to be such a long duration print, I was worried about filament jams and all the other things that could go wrong on a long print.  As it happened, the print went off without a hitch, and produced a near-perfect model.

 Summary and Lessons Learned

  • Although I much prefer to have a ‘real’ project as a motivator when learning a new software package or skill, I probably overreached a bit with such a complex project so early in the learning curve.  Learning how to capture a 3D model from photos, how to use MeshMixer’s sculpting tools, advanced TinkerCad techniques, and a challenging print size and overhang configuration all rolled into one project!
  • The combination of the Autodesk suite of 3D applications (123d Catch, 123d Design, MeshMixer, and TinkerCad) forms a very complete and rich design suite for capturing a 3D object in a form suitable for further development and eventual 3D printing.  The fact that all of these applications are (at least for the moment) entirely free is amazing!
  • the 3D capture and design application world is changing and evolving at warp speed. All of the above apps have serious bugs, deficiencies, and internal inconsistencies, so staying light one’s feet is an absolute necessity.  If it doesn’t work right now, check back tomorrow!  In my case the 123 Catch application literally changed overnight – on day 1 I couldn’t seem to get my capture to stitch at all, and on the next it was all done automagically!  The downside of all this is that skills and/or workarounds learned today may be irrelevant tomorrow, so the need for constant retraining is going to be a fact of life.
  • As in other endeavors, success is 1% inspiration and 99% perspiration.  I just kept banging away at the problem until it gave up and rolled over.  It didn’t matter to me whether my progress was due to my brilliance or just sheer doggedness – either one was fine with me ;-).


ClearNav Joystick Part 1 – From Clay Model to TinkerCad

In a previous lifetime I was a cross-country glider pilot.  This means I would regularly fly an aircraft with no engine up to six or seven hours and cover hundreds of miles without landing.  Expert glider pilots can do this at average speeds approaching or exceeding interstate speed limits.  Since gliders must stop occasionally to regain lost altitude in rising air currents (called thermals), their inter-thermal speed has to be significantly higher than the average, meaning a glider flying along an interstate will easily outpace the cars and trucks below.

Anyway, a friend from that previous life showed me a clay model of a custom joystick handle he was working on.  The model was intended to incorporate a complex instrument remote control panel in the top of the joystick, where the push-to-talk (PTT) switch would normally go.  When he first showed it to me, I was just thinking about getting into 3D printing and in my ignorance I thought this would be a perfect 3D printing project (little did I know at the time!).  Later on when I had just ordered (but not yet received) my PrintrBot Simple Metal Kit I asked him to send me his clay model, and promised him I would at least make the effort to turn his clay model into a finished 3D printed product.  This is the story of how I went from 3D ignoramus to Joystick hero in a few short weeks.


07/28/14 Capture using Autodesk’s Catch/123d:  I’ve gone through this now a couple of times with BZ’s joystick, and I am now starting to get some clues.

  • The first time through was with just some painter’s tape patches placed on the joystick surface to give some reference points.  This worked, but not very well.  The patches didn’t stick very well due to the oil in the clay, and I got a number of unstitched photos.  Also, I couldn’t manually stitch photos together – just never worked

    Joystick with blue painter's tape 'stickies'

    Joystick with blue painter’s tape ‘stickies’

  • Next time through I used narrow strips of painter’s tape, wound around the joystick in several places.  This worked MUCH better, and in fact I had zero unstitched photos, and was eventually able to generate a full 3D STL file editable in 123d Design and TinkerCad (see below).  However, the only fly in the ointment was that the painter’s tape wasn’t completely conformal with the joystick surface in several places, and this came through on the model as raised ridges.
Joystick wound with strips of  blue painter's tape

Joystick wound with strips of blue painter’s tape

  • The third try was to replace the painter’s tape with felt-tipped marker markings. The thought was that this would be more conformal to the surface, and if done properly would also be appropriate for automatic stitching.  However, what actually happened was that the model came through OK, but with many unstitched photos.  Then when I laboriously manually stitched a number of photos into the model, the re-submission crashed – ouch!  This problem continued even if I re-submitted after stitching only one photo.  This was all done with the PC version, so I tried again with the online version.

    Joystick with Sharpie pen markings for surface contrast

    Joystick with Sharpie pen markings for surface contrast

  • In the online version, I see that I have a number of projects that appear to be ‘In processing’, even though they are older (as in days older) versions of the joystick process, and there doesn’t appear to be any way to remove them!.  The ‘Sharpie’ version is shown to be complete, and when I open it in the online version it looks great, but in the online version there is no ‘lasso’ tool for removing all the background elements.


08/07/14:  Working with a newer version of 123 Catch

  • A newer version of 123 Catch became available in the last few days, so I decided to try a new capture using my photos from the ‘Sharpie’ version of BZ’s joystick.  This time when I  uploaded the photos, I didn’t get any unstitched images – yay!!
  • I discovered the ‘mesh resolution’ setting in Catch, and was able to change the mesh resolution from ‘Mobile’ to ‘Maximum’.  This also takes a selection area as a parameter, and re-meshes only the portion of the capture within the selection, so it takes much less time than doing the entire scene.  Remeshing took only a few minutes with the selection limited to just the area around the joystick.


08/09/14 – Still working on the ‘Sharpie’ joystick:  I was able to print a ½ scale model of the joystick, but I discovered it was all solid inside, notwithstanding the ‘hollow’ attribute advertised by the Catch/3D Print operations above.  Also, I wasn’t able to figure out how to undo the ‘minimum support’ setting that left the joystick on its side.  So, I’m making another try at this from scratch and will try to document the steps more rigorously.

  • Started a ‘New Capture’ in 123 Catch, using the 07/28/14 Sharpie photos.  This took a long time to process.  Catch asked for a Capture file name, and suggested ‘Capture_2014_08_09_06_17_31’ (date and time).  When it completed, I was presented with the constructed model as shown below.

    First successful capture of the 'Sharpie' model

    First successful capture of the ‘Sharpie’ model

  • I did an immediate ‘Save As…’ at this point, and noticed I already had a ‘Capture_2014_08_09_06_17_31’ folder and .3dp file saved in the same folder as the original Sharpie photos (140728_Sharpie Photos).  I have seen this before, but AFAICT, this folder and file aren’t usable later – can’t figure that out.  I cancelled the ‘Save As…’ operation.
  • I found a 2011 tutorial at!%20Take%20a%20photograph%20and%20create%20a%203D%20Model.pdf.  This was apparently a presentation at an AutoDesk conference.  This tutorial explained things like the ‘photo lock’ mode (constrains the scene view to just the available discrete camera locations), but wasn’t all that helpful for my purposes.
  • I somehow got into ‘Photo Lock’ (PL) mode and now I can’t get out again!  If I disable PL, I get a blank screen with just the camera locations and the coordinate axes shown.  Hmm, I clicked on ‘show mesh’ and now I have the scene back – weird.  Yep – confirmed that you have to have ‘show mesh’ checked to get *anything*!
  • OK, selected the lasso selection tool and deleted everything around the joystick.  Shit!  I deleted a small section of the mesh, and *then* got a dialog warning me that I needed to make sure I was in the correct mesh quality setting, or edits might be lost.  So I tried to undo the mesh edit, only to find there’s no UNDO function!
  • Used the rectangle selection tool to select just a small area around the joystick for re-meshing (including part of the deleted area from the previous bullet) as shown.  Note that I rotated the view to a fairly high angle so that my selection was restricted to just the newspaper around the joystick – omitting any of the office background.

    Remeshing a selection of the original Sharpie model

    Remeshing a selection of the original Sharpie model

  • Selected the Remesh icon and selected ‘Maximum Quality’.  This produced a dialog with the original capture name (Capture_2014_08_09_06_17_31) which I assume is a reference to the previously uploaded photos.  Curiously, this field is editable, giving the impression I could have used another name – maybe then it would have saved the re-mesh into a different capture structure?
  • OK, the remesh finished successfully, leaving me with a rectangular patch from the original scene.

    Sharpie model after remeshing a selected portion of the original scene

    Sharpie model after remeshing a selected portion of the original scene

  • I saved this result as ‘140809 Sharpie Capture After Remesh.3dp’.  I don’t really know if this will actually save anything or be useful later, but I thought it couldn’t hurt.  I also saved it as an .OBJ file, which might actually be more useful/permanent.  By default, both these files were saved in the same folder as the original capture photos, i.e. ‘F:\3D Projects\Joystick\140728_Joystick Sharpie Photos’.  The .3dp file is only 5.3KB, indicating that (as noted in the 2011 presentation) it only contains references to the online location of the Capture files, not the files themselves).  The .OBJ file is a more respectable 4 MB.
  • Back in Catch, I used the lasso tool to further refine the mesh to just the joystick, and saved this in both .3dp and .OBJ format.  Even after being very careful with the lasso operation, I wound up with a big hole on the right side of the joystick base.  I saw this before on a previous run through, but found that the 123d Print application was able to ‘repair’ the hole – strange.

    After the 'lasso and delete' operation, I have a big hole in the bottom of the joystick!

    After the ‘lasso and delete’ operation, I have a big hole in the bottom of the joystick!

  • Saved this as ‘140809 Sharpie Capture After Remesh And Lasso’ .3dp and .obj.
  • Clicked on the ‘3D Print…’ button to launch the AutoDesk MeshMixer app.  By default, this opens with the joystick in the ‘minimum support’ orientation – no idea how to change it back to the upright orientation (note – as it turns out, this isn’t the ‘minimum support’ orientation – it just looks like it).
  • Clicked on the ‘Modify’ icon and got a warning message about losing unsaved changes.  Clicked OK, and got the following:
  • After fooling around in the MeshMixer for an hour or so, I finally gave up on this model.  I couldn’t figure out a way to add surface material to repair the hole.   Still fooling around, I selected ‘Edits’ and ‘Overhangs’ and MeshMixer crashed – oops!
  • Back in Catch, I opened the file ‘140809 Sharpie Capture After Remesh.3dp’, and it indeed opened the correct project, as shown.
  • This time I used this model to go to ‘3D Print…’, (which launches Autodesk’s MeshMixer app) and got the following default layout.MeshMixerDefault2
  • This is actually a bit nicer to work with, as the section of newsprint gives me a decent X-Y plane to work with for transforming the joystick to the upright position.  After rotating 270 deg around X axis, and then ‘Move to Platform’ to move the base down to the Z = 0 level, I got the following.

    After a 270 degree rotation around the X axis and then 'Move to Platform'

    After a 270 degree rotation around the X axis and then ‘Move to Platform’

  • Hmm, I tried to go back to the ‘Modify’ mode in MM and discovered you can’t do that.  Apparently there are two distinct MM modes – ‘Modify’ and ‘Print’ and they aren’t integrated.  Transforms/Translations in ‘Print’ mode don’t flow back into ‘Modify’ mode – bummer!  To get to ‘Print’ mode, click on ‘Send to Print’.  To get back to ‘Modify’ mode, click on ‘Modify’.
  • OK, finally figured out Rot/Translate in ‘Modify’ view.  The center ‘box’ is for linear scaling for all axes.  The colored arcs are for rotating about the various axes, and the triangles are for translating.  After figuring this out, I was able to rotate the joystick to an upright orientation, as shown.  I still have no idea what the ‘L’, ‘S’, ‘A’, and ‘W’ labels are for.
  • Exported the model as ‘140809_MeshMixer_Rev3.stl’ in Ascii STL format and tried to import it into TinkerCad, but it doesn’t seem to want to import at all.  Imports easily into 123D Design, however.  Tried this trick again with the binary formatted STL file.  The binary version does import into TinkerCad (and 123d Design) OK – yay!!
  • OK, figured out how to use the Select tools to delete the newsprint mesh, leaving only the joystick (hopefully), as shown.

    Joystick after newsprint removal

    Joystick after newsprint removal

  • After this I was able to use the transform tools in ‘Modify’ mode to rotate/translate the joystick into a more understandable orientation, and saved the model as ‘140809_MM_Rev5_RotXlt_bin.stl’.
  • Next I tried using the Edit/Plane Cut tool to cut off the garbage at the bottom of the joystick, as shown below.  I accepted the transform, which gave me just a disk – oops!
  • Tried again, with the cut plane rotated 180 degrees.  This time things worked out much better.  The selection and the result are shown below.

    Plan cut operation with the plane rotated 180 degrees from the original

    Plan cut operation with the plane rotated 180 degrees from the original

  • After proper plane cut selection, the joystick bottom is nice and flat

    After proper plane cut selection, the joystick bottom is nice and flat

Saved this as 140809_MM_Rev6_PlaneCut_bin.stl.  Then I opened it in TinkerCad successfully, as shown below.  Note that the joystick in TinkerCad is still laying on its side, so  maybe the transformations in MM aren’t getting into the export file?


TinkerCad model after successful Plane Cut operation.  Note that the model is on its side

TinkerCad model after successful Plane Cut operation. Note that the model is on its side

  • Tried undoing the rotation transformation in MM and re-exporting.  OK, this worked!  Apparently, the coordinate systems in MM and the rest of the world are defined differently – so if going from Catch to MM to TinkerCad, don’t have to rotate in Meshmixer.

    After undoing the rotations & translations

    After undoing the rotations & translations

  • After this, I went back into MM and used the ‘Flatten’ brush to smooth out some of the rough spots, saved it as Rev8Flattened, and imported that back into TC

Summarizing lessons learned so far:

  • MeshMixer can be used to remove the newsprint background from the Catch export
  • No need to rotate/translate in MM when going from Catch to MM to TinkerCad
  • Probably need to establish a scale in Catch, as the resulting model winds up being very small in MM and TC (3.5 x 6 mm).  OTOH, I can just as easily establish the scale in TC (this is what I wound up doing).

08/09/14:  Starting from ‘140809 Sharpie Capture After Remesh.3dp:

  • Click on ‘3DPrint…’ to launch MeshMixer and load the file:  Opens as ‘2014-08-09-13-06-47_8466_41.obj’ in MM, with the ‘Print’ mode active.
  • Click on ‘Modify’ to get into that mode.
  • In ‘Modify’ mode:

o   Analysis/Inspector/Auto Repair All

o   Edit/Plane Cut & adjust as low as possible with a solid bottom.  This should also remove much of the newsprint area.

o   Choose Select tool with Unwrap Brush active and double-click anywhere in the remaining newsprint area to select it all.  Then hit DELETE to delete it all.  Save this state as a .MIX file, and export it as a binary STL.  Check in TC to make sure it can be imported properly (140809_MeshMixer_Rev4_JoystickOnly_binary.stl)

o   Choose ‘Sculpt’ and the ‘Flatten’ brush.  Run the brush over the entire surface, flattening out minor bumps and wiggles.  Spent some quality time on the top surface, flattening it out for future work.  Went through a bunch of revisions, but saved the last one as 140809_MM_Rev9_Flattened_bin.stl.

08/09/14  – in TinkerCad:

  • Imported 140809_MM_Rev9_Flattened_bin.stl.  This was very small, but it was properly oriented with the joystick upright – yay!
  • Found the ‘all axis scale’ function – Alt-Shift-Corner resizer.  This allowed me to scale all axes until the vertical dimension matched the measured 121.5mm from the original clay model.  Saved this in TinkerCad to ‘140809 Rev 9 Scaled to Clay Model’

Next up – Modifying the basic model in TinkerCad to incorporate the mounting hole for the joystick, wiring passage to the joystick head, and mounting arrangements for an auxiliary switch and the ClearNav remote  head.  Stay tuned!


Mounting Clamp

Clamp for Bicycle Aux Instrument Holder

Just as I was contemplating the dive into 3D printing, a friend came to me with an interesting problem.  Ray is an avid bicycler, and he has a number of auxiliary gadgets attached to his bicycle.  One of these gadgets is an auxiliary instrument holder that clamps onto the horizontal tube from the vertical fork tube to the handlebars, and provides its own small ‘handlebar’ for more instruments, as shown in the following picture

Side view

Side view showing aux instrument bar holder clamped to horizontal fork tube


Side view of aux instrument holder

Unfortunately, after a short time the strap that holds the instrument holder to the bicycle broke, rendering the whole thing useless.  The first time he thought it was maybe it was just a random manufacturing defect, but after going through several that all exhibited the same failure mode, he basically gave up on that model.  When I mentioned that I might be able to help out with my brand-new PrintrBot 3D printer, he brought me the parts.

When Ray brought the broken clamp in, it quickly became obvious what the problem was, and why it was breaking so quickly.  the system uses a metal band that is drawn down into a cavity by an adjustment screw, and this action requires the clamp band to make a right-angle turn right at the nut on the screw.  The band metal is thin steel, and quickly develops fatigue cracks right at the bend.

Mounting Clamp

Mounting clamp interior view showing the capture nut

Mounting Clamp

Mounting clamp and steel strap. Note the break occurs right at the right-angle bend

capture bolt

Capture bolt/nut. Notice the strap residue still on the nut

After some thought, I decided that the solution was not to try and reproduce the system exactly, but to redesign the clamping system to use a standard pipe clamp instead of the steel strap.  The trick would be to ‘cut’ a slot through the body of the plastic clamp in such a way as to still allow the mounting bolt to attach the clamp to the rest of the system, while still leaving enough thickness to prevent the pipe clamp from breaking through the plastic part under load.

After going through a number of revisions and downright mistakes, I finally got a product that worked.  One of the mistakes I made was trying to create the part without a decent set of calipers for precision measurements, resulting in a part that was about 10% undersized in one dimension, and about 10% oversized in the other.  I remedied this problem by getting a very nice Fowler digital caliper from McMaster-Carr.  Another minor problem was that the capture screw was too long, and interfered with the pipe clamp band.  I solved this problem by simply cutting down the bolt a bit with a hacksaw, as the extra length was no longer needed.  Also, as this was my first real 3D printing project, the print quality left something to be desired.  Since this project, I have figured out how to get much higher quality prints.

Bike Clamp Versions

Original clamp on left, mis-sized version in center, final version on left. Note slots for pipe clamp band

After action reporting:  Ray reported that the new clamp worked perfectly on his bike, and seems to be holding up very well.

20140812_071325_resized 20140812_071224_resized 20140812_071253_resized 20140812_071317_resized


Fowler Digital Caliper Booklet Clip

I recently purchased a nice Fowler digital caliper from McMaster-Carr, and I have been very happy with it’s ability to take very accurate measurements.  It came with a very nice case, but unfortunately there’s nowhere to put the little 1-sheet instruction booklet that came with it.  After struggling with this for a few days, I suddenly realized that “I have the the technology”  – I could make a pair of small plastic parts to clip the booklet in place in the case lid!

The photos below show the case with the booklet clipped in place with my new PrintrBot Simple Metal parts, and closeups of the clips themselves.  The posts to which the clips are attached keep the the caliper from banging around in the case, so I used them as the anchor points for my document clip.

Case with booklet under clips

Case with booklet under clips

Left Side Clip

Booklet Clip – left side

Clip Right Side

Booklet Clip – right side

I used my new calipers to obtain the dimension of the hold-down pedestals (sort of a recursive thing, using calipers to measure caliper case components?), and then I designed the 3D part using TinkerCad, exported the part as an STL file, and then printed it on my PrintrBot Simple Metal.  Total time from “Aha!” to finished parts – about 30 minutes! ;-)))

TinkerCad Design

TinkerCad design for the Fowler Booklet Clip

PrintrBot Metal Extrusion Problems

Had my first round of extrusion problems on my PrintrBot Simple Metal, and now I’m older and wiser (well, older anyway).  Turns out the problem ultimately was as simple as adjusting the filament feeder gear tension, but I didn’t know that at the time.  So, I carefully cleaned out the extruder and hot-end tip, using some tips I picked up on the net.  A couple of things that weren’t on other posts, but worked well for me:

  1. After removing the extruder tip from the extruder assembly, I temporarily remounted the extruder on the Y-axis arm and reconnected the heater and thermocouple plugs, and then ran the temp up to 200 or so. With the extruder tip missing, any extra filament material came out the bottom in a fairly large drop.
  2. With the particular extruder assembly I had with my recent version (July 2014) PrintrBot Simple Metal, the top (filament feed) end of the assembly is cool enough to blow into, pressurizing the filament channel.  This allowed me to simply blow extra molten filament material out and confirm that there was a complete, open passage through the extruder assembly (minus the 0.4mm tip at this point).
  3. After blowing out the extruder tube, I screwed the extruder tip back on the (still hot) assembly, and let it heat up.  Then I stripped a length of 30 gauge wirewrap wire I had laying around from a previous lifetime (30 gauge is about 0.3mm) and used it to clean out the now-hot tip.  This take a bit of fiddling, as solid wirewrap wire isn’t very stiff, but it did the job nicely.  In fact, I was able to strip a 4″ length and push it through the assembly from the hot-tip end all the way up through the top, verifying that the passage was completely clear.

After doing all this, I made some test prints, only to discover that the filament was still not feeding properly.  Eventually I tracked this back to an improperly tensioned feed roller bearing assembly.  When I added some more tension, the filament started feeding perfectly.


First prints, Z-axis calibration, and Scaling Issues

OK, so now I have a running  (sort of) PrintrBot and some projects I want to print, but first…

Went through the PrintrBot guide “Setting Up Your Auto-Leveling Probe and Your First Print” procedure.  This was a little scary to start with, as the hot end was really close to the bed (and HOT!) and the Z-axis sensor wasn’t much farther away.  Eventually I got this done to the point where I was ready to start some trial prints with the supplied starter filament, with the usual terrible results ;-).

First attempt at a bicycle clamp part (side view) - ugly!

First attempt at a bicycle clamp part (side view) – ugly!

First attempt at a bicycle clamp part - ugly!

First attempt at a bicycle clamp part – ugly!

Then I tried printing the pre-sliced fan shroud project from PrintrBot, and this came out much nicer

PrintrBot fan shroud

PrintrBot fan shroud – now happily installed on my PrintrBot


This convinced me that the PrintrBot was operating properly, and so I had to look elsewhere for the reason that my bicycle clamp project was faring so poorly.  As it turns out, I had the Repetier settings all screwed up, and once I got them more or less squared away, I got a much nicer print (still not right, but nicer).  My first decent try (center in the photo below) showed me that I had some sort of scaling problem, as the printed part was significantly smaller in all dimensions.  At first I thought this was maybe a PrintrBot mm/mm stepper motor scaling problem, so I tried just scaling up the model by 115% in Repetier, resulting in the print on the right in the photo below.  This still didn’t look (or measure) correctly, so I was left scratching my head.

Original part on left, first try (way too small) in center, scaled by 115% on right

Original part on left, first try (way too small) in center, scaled by 115% on right


So, I decided to do what I should have done all along, and attack the problem methodically (well, I am a professional engineer, after all!).  I downloaded the 20mm hollow calibration cube from ThingiVerse and printed it. This experiment started with an STL file, which was then sliced and diced in Repetier, thereby testing the entire STL – Repetier – GCode chain.  The result, as shown below, convinced me that both the Repetier and PrintrBot parts of the system were working properly.

20mm Hollow Calibration Cube

20mm Hollow Calibration Cube


Unfortunately, there were only two things left in the system – TinkerCad where I created the 3D model of the bicycle clamp, and the person (that would be me) who created the model.  After a couple of quick experiments with models of known dimensions, it rapidly became clear that TinkerCad was not at fault – leaving only the nut behind the wheel as the causal factor for the errant dimensions.  In my defense, I really didn’t have a good set of calipers, and the measuring tools I did have were all calibrated in inches, so I plead for mercy from the sentencing judge (I did jump on the McMaster-Carr site and order a decent set of mm/in digital inside/outside/depth calipers).

By the way, I have been using my wife’s really nice Canon ‘PowerShot’ SX260HS digital camera for this work, and I’m really pleased with the results.  It’s super easy to use, and produces 3000 x 4000 pixel images – way more than enough for everything I need.  Easy to upload photos via the built-in USB connection, too!  In fact, I’ve been using it so much that my wife has pretty much given up on ever getting it back ;-).

Stay tuned!






3D Printing

I’m just now getting into the exciting new world of 3D Printing.  It is pretty clear that the entire DIY 3D Printer is wildly chaotic and changing at a very rapid pace.  This reminds me a lot of the early Personal Computer days (when the term ‘Personal Computer’ meant something that could fit onto a normal-sized office desk!). In those days, PC makers appeared and disappeared on a weekly (if not daily) basis.  I remember buying a ‘Columbia’ PC (named because the company was located in Columbia Md).  Its claim to fame was portability – if you wanted to think of a 30-40 lb package as ‘portable’!  Almost all of these PC manufactures were gone in just a few years, I suspect the same thing is going to happen in the 3D printer market.  I wonder if there will be a Dell and/or a Microsoft/Apple of 3D printing, or if the entire industry will go off in another direction entirely.  One thing is for certain though, we are witnessing the dawn of a new era that will completely remake global industry and society.  You can’t download pizza yet, but you *can* download the designs for, and print, just about anything else!

After doing some research into the many many offerings out there, I decided to go with the PrintrBot Simple Metal Kit.  I have a pretty strong background in Electrical Engineering, and can find my way around basic construction toolboxes, so I figured I should be able to handle the kit and save some buckazoids in the process.

The kit construction turned out to be very straightforward, and the kit instructions on the web were pretty complete.  I did have some minor problems when it turned out that a late addition to the kit (a small DC-DC converter PCB for the inductive build-bed sensor) wasn’t referenced in the kit build instructions – oops!  A couple of quick emails to the PrintrBot support team, and some judicious Googling got me the information I needed to correctly integrate the new part.

In any case, here are some photos of my completed Printrbot Simple Metal.

First 3D Printer

My first 3D printer – a PrintrBot Metal Simple Kit

Underneath the covers.  Note the extra white cable tie mounts

Underneath the covers. Note the extra white cable tie mounts

After getting the PrinterBot completed, of course I now had to actually *do* something with it.  This required me to learn the software side of the house, and it too is a bit of a wild-west ride at the moment. It is entirely possible to design a part (or capture a 3D model from uploaded camera still photos) without paying a cent for software.  For initial 3D design, Autodesk has 123D Design, 123D Catch, 123D Print and TinkerCad (recently purchased).  The Autodesk apps come in standalone and web-based flavors, with the exception of 123 Design (which is being shut down due to problems with the required plugins) and TinkerCad.  All of these have their own ‘special’ learning curves, complete with a wide variety of bugs and gotchas.  Using any of them requires a *lot* of patience to work through missing functions and random crashes.  However, notwithstanding all the problems, the functionality of some of these apps is simply amazing, especially considering it’s all free! From nowhere to actually usable in just a few years (or months!).  For 3D printer management there is Repetier-Host – again free for the basic model.  This app accepts STL files from the design side and manages the process of ‘slicing’ the model for a 3D printer (using one of a number of plug-in ‘slicers’) and then sending the ‘G code’ instructions to the printer itself.  All in all, a hugely confusing (but exciting in a masochistic sort of way) landscape littered with bugs and obstacles on the way to that perfect 3D print.

Stay tuned!