OpenROV 599 — Build Diary 03

Cleverness and Mistakes

All three of my cats find the OpenROV build fascinating. Lyra was "helping" for all the steps described in this update to my build diary...

All three of my cats find the OpenROV build fascinating. Lyra was “helping” for all the steps described in this update to my build diary…

[3 May 2015]
One of the clever things about OpenROV is their use of everyday items to do the job in the machine. Case and point: the use of syringes in today’s step. Small tubes are needed in the end-caps, so they are cut from common, everyday 1 ml syringes.

In this step they have you put the syringes in a vice, hacksaw off the bits you need, and then clean up the saw cuts. I don’t have a small vice on my bench, and hacksawing didn’t really seem like the optimal way to do this, so I decided to so this slightly different.  Instead of sawing off my syringe, I decide to use a pipe cutter — it will make a more precise and more square and clean cut.

Of course you can’t just willy-nilly try something and assume it will work, so I did a test first. The ends of the syringes are discarded, so I made a test cut on the end that was to be thrown away.  It works great! After sanding and filing the edge flat (it was already pretty square), I deburr by twisting Phillips head screwdriver in the end, but there is almost nothing there to remove.

When I make the cuts on the piece of the syringe to keep, one cut is just past the plunger stop. There are two bits to the syringe here — an outer shell that the pipe cutter goes through just fine. But inside that is a nozzle, that is supposed to slip into the needle attachment. The pipe-cutter can’t reach this bit, so I simply roll the syringe while pressing on this bit with my Exacto knife, it and it shears it off nicely.

[9 May 2015]
IMG_6101Tonight I go through Steps 13-18 of my instructions, to assemble the endcaps.  This is a messy messy step, as it involves doing large surface-cementing between flat round disks, and filling the gap with copious amounts of cement that bleeds out. The instructional video posted by OpenROV was quite helpful to watch before I started!

I do okay with the first one, but it’s a bit messy.  Quite a bit of end-cap marring by cement running everywhere, but I think I do okay — there are no big crazy bubble areas between the panes of acrylic — the bonds look good.

IMG_6102

On the second one I made a BIG MISTAKE. Despite being warned in the video, depsite being warned in the instructions, and despite attempting to be careful and lay the parts out and see how they are going to fit before I even touched the cement, I glued the last endcap flange disk on BACKWARDS!

The two endcaps are supposed to be mirror images of each other. Somehow I just flipped it all in my head when I was putting it together (maybe it was the paper peeling where I flipped it? or juggling the cement and disks together? or maybe just my L-R dyslexia?)  In any event BIG MISTAKE.

So there are three possible courses of action:

(1) Acquire new parts and build a new, correctly oriented assembly. This is probably my first choice.

(2) Perhaps an edge could be cut down to give the right symmetry to the end piece; this would leave a flat edge on one side of the flange, and I don’t know the ramifications of that.

(3) I could have someone cut me new parts, and I could reassemble this stage one more time, correctly.

I emailed support at OpenROV and asked about purchasing replacement parts. We’ll see what they say.

The next stage involves soldering, but I’m still fuming so maybe I’ll wait to do that until tomrrow! 😛

OpenROV 599 — Build Diary 02

[2 May 2015]

An old shop trick of mine, to avoid disasters.

An old shop trick of mine, to avoid disasters.

Today I began assembly of the infrastructure of the ROV — that means “cementing acrylic.” I’ve never done this before (other than styrene models), but I dutifully watched the TAP plastics video that the instructions pointed to. Even so, I think I was still a bit unprepared for how free streaming the cement really was!

None the less, things progressed steadily without too many hiccups. Copious notes are in my OpenROV599 CompBook, but I capture the important points here for reference. The “STEPs” labeled are the step labels in the instructions [2014-03-20 version in the version history].

The pieces for today all laid out.

STEP 003: I got the first two pieces aligned pretty well, but the third one was off just a tiny smidge; you can’t see it well by eye, but I can certainly feel it. Shaving it down with a knife didn’t seem to be workable, and I didn’t want to sand it for fear of rounding off the whole assembly, making contact surfaces problematic.  I test fit it onto the Lateral Shroud Support, and it seemed tight enough, so I didn’t worry about it.

STEP 004: Note in this phase of the instructions, the piece is referred to as “top piece of internal structure” and as “top plate“. It is called top plate on the line schematic drawing shown in Step 2 of the instructions.

IMG_5951

It’s not easy to see from the instruction pictures which way it all goes together. If you look at the Top Plate face on, it kind of looks like a barn — the handle is aligned in the vertical direction of the barn, with the finger holes close to the roof, and the horizontal piece (the Lateral Shroud Support, bonded to the handle) parallel to the floor.

STEP 005: Not all the parts used in this step are named in the instructions. They are (corresponding to the line schematic in Step 2 of the instructions): Horizontal Motor Mount, Axial Shroud Supports, and Vertical Motor Mount.

motorMount

Note that the shape of the holes in my Vertical Motor Mount are not the same as those shown in the line schematic — mine have slightly rounded inner edges, rather than flat edges. This was the first step where I had to really pay attention to the pictures and try to understand how to put the parts together — it’s hard to see what is going on with that clear acrylic!

IMG_5952

I did my bonding at this stage in 3 steps: (1) Bond motor mounts to the left Axial Shroud Support. (2) Bond motor mounts to the right Axial Shroud Support. (3) Bond the interface between the Motor Mounts.

STEP 006: This took me a little while to decipher from the pictures how to put this sub-assembly together. The pictures are not obvious, and hard to parse. The motor mounts are bonded to one end of the Axial Shroud Supports (see last step). The open edge of the Vertical Motor Mount bonds to the lower face of the Bulkhead (under its central U shape); the edges of the Axial Shroud Supports also bond to the Bulkhead (on either side of the central U shape), with the tabs fitting into pre-cut slots.  When correctly put together, the Horizonal Motor Mount is parallel to the Bulkhead.

The Bulkhead Brace is laminated onto the long edge of the Bulkhead to make it double thick. It is under the central U shape of the Bulkhead, and contained by a slot formed between the Axial Shroud Supports and the Bulkhead. Tabs on either end of the Bulkhead Brace match tabs on the Bulkhead.

As noted in the instructions, some later kits have larger plastic heads on the end of the Bulkhead Brace than shown in the pictures. That is true of my Bulkhead Brace — the brace is large enough to cover the tab holes in the Bulkhead.

STEP 007: Join the two major sub-assemblies at this point, and then add some bracing.

CONCLUSIONS TODAY:

(1) Photographing clear acrylic so it makes sense is HARD (mine, shown here, and the OpenROV guide photos just don’t always make sense!). To this end, pushing parts togther and handling the structure and looking at it from all angles while staring at the pictures is crucial to getting it all together right. Sometimes to figure it out, I had to step ahead a step or two to see where it was all going to fit together.  Don’t pick up the cement until you’re sure you got it right!

IMG_5972(2) The acrylic cement is crazy stuff. Holding tension on parts means there were a few times it ran under my fingers too. That means there are several places where my fingerprints are molded into the infrastructure. Oh well; that just means 200 years from now, when marine archaeologists find Jack on the bottom of Lake Michigan, they’ll be confident this was really my OpenROV! :-)

OpenROV 599 — Build Diary 01

[15 Mar 2015]

1455144_10201131592353663_488880109_nThis is my first OpenROV build. I purchased my OpenROV kit in the fall of 2013, the moment I first became aware of its existence (sadly, I don’t remember exactly how I stumbled on them). I had just moved to Chicago, and the proximity of Lake Michigan was rekindling the interest in ROVs that had lain dormant since I left California after my postdocs there.

We had just moved to the city, and were living in a small apartment, and I had not sorted out how to have any kind of hobby space, so my OpenROV kit sat waiting patiently in its box. Finally, we moved to a slightly larger apartment, and I carved out a hobby space!

benchI used to have a garage, and a full out workshop with benches, power tools, the works. I had to be far more compact since I’m confined to an apartment. I wanted a solid surface I would work on, with plenty of storage. My workbench is a 30″x72″ work surface, setup on an array of cubeshelves. I made the surface out of softwood (pine boards) supporting bamboo panel flooring for my work surface. The top of the bench is 37″ off the floor, so this is definitely a “standing” bench.  I’ve been meaning to write an Instructable about my bench; I’ll have to do that sometime (after my ROV is done!).

notebookSTEP 000: Record keeping is a BIG thing with me. I have notebooks for everything that I do, and the ROV isn’t any different. In addition to this electronic diary, my day to day notes and work associated with the build are being recorded in a composition book dedicated to this project. Per my normal habits, it is kept diary style, with numbered paged and dated entries — everything goes in the notebook.  I call this notebook “OpenROV599 CompBook” in these entries.

STEP 001: First step was unboxing my OpenROV and inventorying the set against the Bill of Materials (BoM) that is listed with the build instructions. I used the 28 Jan 2014 version.

Unboxing everything in the kit and checking it against the Bill of Materials.

Unboxing everything in the kit and checking it against the Bill of Materials.

A few observations and oddities about the process of checking against the BoM:

  • The BoM is written as if you are building your ROV from scratch, rather than from a kit. As such, the first entries are for sheets of acrylic; in the kits, you have pre-cut parts, and there was no way to know if you had all the parts or not!
  • The Construction Materials listed in the BoM are not the same as those listed in the instructions themselves; I followed the instructions. :-)
  • In some instances, some colors for the parts would have been extremely helpful. Especially the first time I pull all of this stuff out of the box, I have no idea what any of it is! For instance, the BoM lists “Wire Sleeve Material.” This was yellow in the kit, so saying yellow would have helped me find it, rather than process of elimination (the “Wire Sleeve Material” also is erroneously listed as being 30mm long, when it is 30cm long).
  • There was one screw missing from my inventory (An M3x10 nylon pan head screw). Scanning ahead in the instructions, there was a place where it is used and they note that early versions of the kit did not include it, and suggested we just lift one from elsewhere in the ROV. That doesn’t sound like something I would do, so I’ll order some more from McMaster Carr.

My copy of the BoM that I checked against is on pages 2-3 of my OpenROV599 CompBook.

STEP 002: I’m always thinking that I might want a new part or need to replace parts. I could trust that the OpenROV folks are going to be there always, but who knows whether or not they’ll be able to provide parts in 20 years! What if one breaks and I’d like to repair it sooner than I can get a new one? There are all kinds of reasons I could imagine needing a copy of the parts I started with.  I decided the best plan was to scan them all into a PDF, so I could print out new 1:1 copies if I ever needed to.  The parts are transparent acrylic, so after experimenting a bit I decided I could get good scan results by putting a piece of blue paper behind them when I conducted the scan.

I print out my scans and put them in my OpenROV 599 CompBook on pgs. 7-11. I number all the parts and as I use them in the assembly, I’ll note on those pages the first step where the part is used.

And so it begins…

imagineRockOn the corner of my desk, I have a small, smooth river stone, just big enough to fit in the palm of my hand. It has been engraved with a single word.

Imagine.

I am a professional scientist by trade, and more than anything else, the trait I value the most in myself, my students, and my colleagues, is imagination. All too often when we learn about science as kids, we are taught that it is a little box with explicit rules that must be obeyed (sometimes called “The Scientific Method“). While there is some truth in that notion, nothing could really be further from the truth. The beginning of all science is imagination.

We imagine what the world should be like.

When we see the world, we imagine why it looks the way it does.

When faced with puzzles and problems, we imagine ways to solve them.

When we want to explore a far away place, we imagine how to do that.

Perhaps not surprisingly, my “hobbies,” the things I do outside of my professional work, all have a sciencey flair to them, but what they really have in common is imagination. My hobbies are all endeavours that connect me in some way to the Cosmos, to fuel that crazy little muse in my brain called my imagination.

OpenROVI already blog regularly about science topics at writescience.wordpress.com (go check it out!), so why start this blog? The impetus to start this blog was my acquisition of a small, underwater robot known as an OpenROV. I decided I had to have a place to record my efforts to build and operate one. Over time, I expect we will delve into other things I do (build telescopes, fly high-altitude balloons, rocketry), but my ROV is the beginning. I expect all things being equal, it won’t be as polished and clear as I try to be at my other blog; I think of this more as “my diary of imagination and adventure.” I hope you enjoy riding alongside.

koshI have a healthy respect for great works of the imagination. I try not to let my mind be fettered by scientific inaccuracies in movies and television shows. Instead, I focus on the fact that these works of art are endeavouring to help us learn something about ourselves — they are telling stories about us, right here right now, through the lens of science fiction. I gather deep pleasure and motivation from these stories, fueling my ambitions not because they present some target for my scientific work and hobbies, but because they inspire me to do what I do and tell the stories of what I do in the hopes of moving some one with tales of the Cosmos the way they have moved me with tales of imagination. Hence, blogs like this one. My allegiances in the world of science-fiction fandom are many, but J. Michael Straczynski and Babylon 5 hold a special place in my heart. The title to this post comes from Babylon 5, spoken by the enigmatic ambassador Kosh as our heroes took the great leap off into the unknown sea of the future.

And so it begins…