Author: Shadow8472

Posted on

Headphone Repair?

Good Morning from my Robotics Lab! This is Shadow_8472, and today, I am trying to fix a pair of headphones that popped a joint while I was off on vacation this week. Let’s get started!

I’ve had this set of headphones for a while now, and I’m not always the most careful with my technology. I often leave them on top of my cluttered desk or computer tower, and the household cats often pilgrimage to the window behind my desk. Be it from my cat or my klutz, the headphones often would wind up falling to the floor, and I would count my blessing when they still worked each time they tumbled.

Typically, I’ve had headphones fail at the micro-USB connection from the wire to the headset. This time, I stuffed them in a backpack along with a couple other laptops and a keyboard. Sometime between home and our second hotel, one of the sides had popped out, likely when a dog crate shifted into the backpack momentarily. I tried to push the piece back together, but I was afraid of damaging it, partly because we’d had the opposite problem happen to one of our dogs’ Gentle Leaders (a training tool worn on the dog’s head).

With the lack of enough progress on the Pi case I’ve spent months slugging on about, I noted the lack of broken-looking individual parts on my headphones and decided it wouldn’t hurt to disassemble the hypermobile joint and put the whole thing back together correctly.

I started by removing the four… three of the screws holding what was left of the wayward side together. The forth one was a little stubborn, but it eventually came out. The piece itself had a little more resistance, so my father and I coaxed it out gently.

Exploring the inside was a little disappointing. The first sign this wouldn’t be a successful mission was the tweaked, plastic fingers meant to hold onto a grooved peg (helpful for) earpiece rotation. Additional bad news came when I spotted an actual crack in one of the brackets.

For the purposes of the blog, I decided to pull the other piece off for comparison. Remember all those drops? The teeth on the “good” removed piece were well on their way to deforming in the exact same way. The backpack getting crushed must have affected only the one side and was either enough to finish the job or do it from scratch.

Either way, I won’t be able to repair them as I’d hoped. I wouldn’t trust my 3D printer with something so delicate, and even if I did, I don’t have a pattern or a way to scan the “good” piece (so it can be mirrored). The plan is to screw the pieces back where they go and either cache in on a warranty or save them for parts.

Final Question: Have you ever had to back out of a repair project when its apparent difficulty level spiked?

 

Posted on

A Spot of Network Maintenance

Good Morning from my Robotics Lab! This is Shadow_8472, and today, I am scratching around for something to talk about and I’ve come up with reviewing a home network crash this week. Let’s get started.

Years ago, I was staying in the dorm at my university as a Freshman. The walls were concrete, so they didn’t have the campus WiFi installed. If you wanted your own WiFi, there was a hard rule: “Absolutely no routers” because it messes with the network. Instead they had these wireless access available from IS (Information Services, the local version of IT). Each room had two Ethernet ports (and two disconnected phone connections thrown in for free), and even though I was alone in the room, I had my desktop, laptop, and now an access point. Hard wire is much better than the unreliable WiFi, so I ended up picking up this Ethernet switch.

An Ethernet switch is a step above an Ethernet hub, which was also allowed. While a hub just repeats each signal it gets to all the other connections, and the wrong connections ignore them, a switch directs signals to where they actually need to go. I ended up with an eight way switch.

My switch served for the next few years and eventually got integrated into my family’s home network system, where it’s been serving with all but one connection for a while. This week, the Internet cut out on us, all devices at once. My father was the one who actually talked to tech support, but after they told him his router was bad, he did some additional diagnostics, which pointed to my switch having failed.

My mother and I went to buy the replacement the next morning, and I was a bit perplexed when I opened the box. The old one was simple: plug and play. This new one comes with a CD, and an instruction guide for setup that doesn’t even work straight away with Linux. At this point, I’m getting conflicting impressions: Linux is king in the server world and prominent with people who are into computers, but they only seem interested in catering to Windows users.

I ended up ignoring the fancy setup for now and tried plug and play. It works. I cannot imagine why they would not list that as an option. It would have been a bit less frustrating if they had just said so right away and stated their extra software as “optional, for enhanced performance” or something like that.

Update: As I was finishing, the Internet dropped out again. After it’s stable again, I may want to take another look at my switch to see if it was working all along. In the meantime, a router reboot fixed it for now.

Final Question: What was the last piece of computer hardware you wore out?

Posted on

MineCraft 1.13 Cave Spider Farm Design

Good Morning from my Robotics Lab! This is Shadow_8472, and today, I am taking a break from the regular content on my blog and doing a tutorial on this easy Cave Spider XP farm I’ve developed with a little help. More on that later. Let’s get started!


Minecraft has a small zoo’s worth of farmable mobs, but one of the most challenging is the Cave Spider. With its ability to climb any surface as if it were covered with ladders and its tiny hit box, able to slink through all but the most airtight of hastily built walls, these pests are native to abandoned mineshafts, and nowhere else. The only reason anyone might even consider a Cave Spider XP farm is because of how often multiple spawners can generate close to one another.

.
This tutorial assumes you’ve already found an abandoned mine shaft full of cave spider spawners. Once you have a bunch of spawners captured, write down or take screen shots of each spawner’s coordinates. Remember, mob spawners only activate if you are within 16 blocks, so the farthest apart two spawner blocks can be is 32. If you aren’t sure if two blocks are in range, use the Pythagorean Theorem generalized for three dimensions, √[(x1-x2)²+(y1-y2)²+(z1-z2)²].


If you are looking to develop more than two spawners, which is usually the case if you are going to go for cave spiders, you’ll want to actually graph their x and z coordinates to filter out the false hopes a purely Pythagorean approach can yield. I recommend using a Geometry program like GeoGebra. Draw a 16 block radius around each spawner’s point and look for overlap. Once again, this won’t give you any hard positive results, but it will give you a fairly good idea of what to expect and how big your spawners’ overlap area is so you can start designing your grinding room.

You’re mostly on your own for the next part, since there is a plethora of possible arrangements between spawners, collection systems, and collection points, but I can give a few general tips.
Spawners won’t spawn mobs if too many are within a 9x9x9 box of the spawner block, centered on the exact middle of the spawner block. For maximum efficiency, drop your spiders down four blocks, then at least another two and into a water collection system.


Cave Spiders’ alleged super powers end when they can’t stick to ceilings. We can exploit this by using Iron Bars, Glass Panes, or the like to make a little overhang they can’t climb past. (From here on, whenever I say, “Iron Bars,” just use the narrow block of your choice.) To keep them from climbing into a corner and building up, we can use flowing water at the top to push them off the wall.


Here’s a cross section of my personal collection system. Important notes include highest part of the floor (the system need not be perfectly symmetric) is 4+2 blocks below any spawner above it, There are no water source blocks in the collection area itself, and the final water flow ends on the Iron Bars. Build the middle of the trough similarly, digging down whenever you run out of water instead of adding sources. The pistons are for a gimmicky lighting system I only recommend for those brave enough to deal with lava lighting.


My main innovation for this tutorial was this part right here. By lining the top of the transportation tunnels with top slabs (Trapdoors/Iron Trapdoors should also work and look nice), we don’t have to dig out so far to get that little tip of water to push the cave spiders back; a source and single flowing water should do. Once you are in the tunnel, feel free to use water sources whenever you drop the floor.


When you get to a corner, drop the waterline again and add a source block. On the upper “water rim,” be sure to use an upper slab so the spiders don’t get stuck on a quarter of an exposed block. Just carry the inner corner around the turn, but be sure you don’t accidently turn your flowing water into two lines of source blocks.


Here’s a picture of a Cave Spider grinder design from SteelToad, a colleague of mine from the server I play on. The Spider input is two wide, so I like to put a two wide soul sand bubble elevator in line with it and pipe them directly to the kill chamber.


Back in the plumbing, the entrance of the elevator is only a block wide. Unfortunately, we’ll need to use a pressure plate or sign to contain the elevator water and rely on the spiders pushing against each other to move things along. While we’re at it, we can lose the bars by adding water streams from the sides to guide the cave spiders into where they belong.

A final note: If you plan on any serious AFK time, be sure to include an auto killer switch. When I built this in survival, I used pistons to change the direction the elevator sent the spiders. Other than that, add whatever you want in a Cave Spider farm. Just don’t get too close to the spiders when whacking at them, as they can still occasionally bite.

Final Question: What other design improvements would you add?

Posted on

A New Tool Part 10

Good Morning from my Robotics Lab! This is Shadow_8472, and today, I am covering the finishing touches of the physical side of my new prototyping assistant. Let’s get Started!

I left off with the glue mask drying on the ghost’s foot area. When I peeled off the tape from around the stuff I actually wanted to paint, I ended up pulling bits of the glue mask off along with it. I ended up spending the week touching up the glue and waiting to paint the foot.

The lower half of the Pi case finally did get painted, but at present, I am waiting to put a clear coat on the whole thing. Order of operation keeps getting in my way, though, as the upper half of the case needs some touch up paint from where I goofed on the original masking.

In other news, I went to that workshop again. I hooked up the camera to the Pi and had it look through the pinhole. I was expecting a blue haze around the picture’s outer rim, but somewhere in the process of painting, likely when I was first painting the blue pupil and I stuck a pin in it, I must have expanded the hole just enough so it doesn’t show.

To finish this week’s project (late) I just need the touchup finished with a paint brush, a light sanding to remove the strokes, and a clear coat to protect the paint. After that, the foot’s masking can come off and I can mount the Pi board and tape the camera in place. As the file I printed up is meant for a slightly different board, I will only be able to use two of the four screw holes that align at once. I’m slightly worried about too much torque on the Pi’s circuit board, but if I’m always careful, it shouldn’t be a problem.

Final Question: I’m slightly worried I won’t have enough to write about when I get around to programming the thing. Will you be up to more technobabble style posts when they come?

Posted on

A New Tool Part 9

Good Morning from my Robotics Lab! This is Shadow_8472, and today, I am bringing another slow progress report. Let’s get started!

In retrospect, I spent a little more time on my project than I would likely have given myself credit for. Nevertheless, I didn’t make my goal of fully painting the case. I had to plan every step before hand, and carry them through.

Early on in the week, I once again sacrificed the texture of my fingertips as I sanded the Pi case. When I sanded the pyramid, aside from only doing half of it, I had the sandpaper flat. Flat sandpaper doesn’t work so well with curved surfaces unless you have some sort of machine to sand evenly. I’m working by hand, without any power equipment. I used different grits, mainly skipping some of the lower ones and working with something a little more appropriate to the quality it’s already on.

The 660 piece I used up was the only one in stock, so I ended up getting and using 1000 grit for polishing it. I will say, though, it wasn’t the surface without blemish I was expecting. I kept getting these rings as if the vertical layers were slightly scaled wrong.

My technique while sanding evolved as I worked. At first, I was just trying to conform the paper to the surface to sand. After a while of mildly frustratingly flimsy sandpaper slowing me down, I folded it over and focused on smaller spots at a time. Later still, my father got in there and gave me a wash cloth to use as a flexible sander block.

After sanding came masking. Now, I have two pieces. The head, and the body. The head is basically a dome with eyes, one of which I hollowed out for the camera. The body houses the Pi and has screw holes on mini shelves and ventilation holes stuffed into a waffle cone “foot” section. After an overnight test on the test pyramid, I painted the eyes first. I got out the blue painters’ tape and covered the whole outside of the head. Then I took a razor blade and cut out the pupils, scratching the lens pupil in the process. Oh well. After spraying that blue, I found a tip online to use some Elmer’s school glue as a mask. I covered the pupils in glue and uncovered the rest of the eyes before the glue finished drying. When I peeled back the glue, I realized this project might not look absolutely perfect, but it’s going to be far from ugly. I missed a few tiny spots with the glue, and still have to do a little cleanup. As it stands now, I have two coats of red paint on the main dome.

The foot is another interesting story. I decided early on I wanted to leave the inside of the case alone. I also added the uneven underside to the immunity. Since glue gets into annoying, little places, I went with that to mask off the inside of the case and the bottom of the foot. However, the inside of the case has some spots I doubt I will ever be able to clean, such as screw holes. So I covered the little holes on the inside, masked off the parts I wanted covered, and applied glue as the positive mask; this is where it stands now, waiting for the globs of glue I used to finish drying. Once that’s done, I will remove the negative mask and paint the lower half. With any luck, I will just have to get the glue out and install the hardware and I will have a tiny prototyping assistant for many projects to come.

Final Question: With any luck, I will be working on the software side by the end of next week, but I still don’t have a way to physically make the high frequency to repulse naughty cats. What would be a good place to look?

Posted on

A New Tool Part 8

Good Morning from my Robotics Lab! This is Shadow_8472, and today, I am taking a little side quest to try out some techniques so I can paint my Raspberry Pi case and have it look good. Let’s get Started.

I decided to paint one or more of my old test prints. The first two were an acrylic paint straight onto the plastic. It didn’t work all that well. I couldn’t even get a small piece devoid of any brush strokes, and I want a smooth finish. On top of that, I was able to easily scrape off part of the paint with my finger nail after it was fully dry.

My next step took the rest of the time for the week. I moved over to a goal of spray painting, so I printed up another pyramid from when I tried to figure out if the percent completed was in terms of time, z axis, or plastic used.

I was thinking of testing both sanded and unsanded surfaces, so I was going to print it twice, but I cut back and only sanded half of it. I still have the original around, but I wanted to leave that one alone as sort of a memory piece. Printing it again reminded me of how difficult the raft was to get off.

After getting most of the raft off, I got out the sandpaper, going through grits of 80, 150, 220, 320, and 600, using water for the fine grits on “waterproof” paper, and I actually got it pretty smooth. I did get the stubborn part of the raft off. After going back and forth on what part of the model to mask off first, I decided on using some blue painters’ tape to mask off the very top and dangling the whole thing off that. I applied two layers of white spray paint, including the bottom (primer included in paint). I let it sit for a day over Sabbath. After it had the recommended 24 hours to dry, I masked off the rest of the pyramid body and painted the capstone yellow.

As I peeled back the masking, I saw a few spots where I didn’t make sure the tape was perfectly creased in there and it leaked in. Lesson learned: use your thumbnail ensure the quality of your masking.

In the end, I like the smoother sides. The little ridges from printing poke out a little, and I’m not sure if they are catching dirt or wearing through, but I think it may be worth it to put the bit of extra effort to make the final product just that much better.

Final Question: I’ve been thinking of including a sub-title for multi-part projects. This one would have been something like: “(Side Quest: Painting Skills)”, but that makes it harder to just edit the URL to jump to adjacent posts. I know I don’t likely have enough regular readers to warrant this question, but should I include subtitles?

Posted on

A New Tool Part 7

 

Good Morning from my Robotics Lab! This is Shadow_8472, and today, I have a short post because the printer did most of the work. Let’s get started.

The printer took a little over two days to print. It went all right, except one time when the PVC pipe extending the filament holder slowly slipped out. It made a loud sound and I was able to repair the accident before anything print-ending happened.

Cleanup was actually not as bad as I was expecting. As with the practice ring, the slot to accommodate the HDMI, power, and sound needed attention. But the custom eye slot was one of the cleanest to come out of the printer yet. It only had the single most tricky tag to remove of all. After I poked it with a razer blade for a while, my father used a candle to heat a blade to melt it off. I’m a little annoyed some soot ended up sticking, but the artifact I don’t understand is why a tiny hole on the side popped into existence even after a final test print to make sure such a thing wouldn’t happen.

As it stands, I will be painting the eyes at least. This will at least disguise the little hole, but it will also blend in with the camera in case I ever decide to use it as a hidden security camera. One thing I didn’t account for was the paint when making the camera hole. I hope it doesn’t come to it, but I likely will have to drill the hole a little bigger.

Whatever the case, this case was designed for a slightly different Pi. I’ll only be able to use two of the four screw holes, but that should be enough to hold the main board in place.

Final Question: Printing the case turned out to be a full length project. How long do you think I will need to perfect the software?

Posted on

A New Tool Part 6

Good Morning from my Robotics Lab! This is Shadow_8472, and today, I am covering a lot of progress toward a viable Pacman Ghost head for my Raspberry Pi case. Let’s get Started.

Last week, I was stumped with fixing the a mesh representing my Pi camera. I reached out to my fellow TitanCraft members (Patrion MineCraft server of Tango Tek) and one player by the screen name of Rhyno talked me through fixing my mesh. I ended up doing it my own way, but I encountered a recurring motif of the week, having a real person who knows something in the field or program I’m working in is very good way for me to pull the answer to my own problem out of my own head.

I fixed the mesh and got Blender to produce a smaller cut out for the camera. It looked workable, if only I didn’t have to clean out a little bit of gunk blocking the camera from fitting snugly. The potential issue was compounded in my mind because of the awkward angle I’d need to get at it (from the bottom of the case).

I set that aside and turned my attention to the other big problem I wasn’t looking forward to: the ridge to accommodate the Pi’s HDMI, power, and audio jack. I used a cube in Blender to cut off most of the ghost head and I printed the base of it. To my surprise, while it still deformed, it didn’t cave in as badly as I expected, so I was hopeful a small fix could save everything.

I took both problems into a small workshop I recently joined. Both problems were basically resolved, “Tough,” and, “Tough,” but each one came with a “…but here’s why:…” segment. For the first problem, 3D printing is still fairly early on in its history, some cleanup is expected. For the second, I just need to trim away the junk strands and nobody will be looking up and under at exposed infill, and if I paint the whole thing, like I’m planning on doing for the eyes anyway, the paint will cover the hole anyway. While I was at the workshop, the instructor (for lack of a better word) had me plan my next few steps.

I wanted to learn about getting a support structure to work, but my previous attempt months ago didn’t work. The problem then was that I was trying to print an ugly lollipop on its side and the support structure didn’t do anything. This time though, I modeled up a tiny table and it printed correctly, support structure included. The piece was so delicate I busted off two legs when I took it out, but by then, I already learned what I needed for it.

Also a recommendation from the workshop was that I print up the ghost head at a quarter scale. It worked fine without a support structure, but because it was so thin, the printer left a tiny hole in the top.

I expect the full case to be finished next week. But if the Pi needs an ABS case, I guess I know what needs to happen then. I already ran a simple test where I left the Pi to heat up an interrupted print of the base, so I’m hopeful at least.

Final Question: I’m almost done with the hardware part of this project, and it’s taken a while. How long should the software take?

Posted on

A New Tool Part 5

Good Morning from my Robotics Lab! This is Shadow_8472, and today, I bring part 5 of the construction of my Raspberry Pi prototyping platform with a camera. Let’s get started.

I am behind where I wanted to be. It’s the classic game of Hurry Up and Wait, only I waited too long. Things have to be done in order, and all the stuff where 2.5 hands were required feels like it was at the beginning.

It turns out whatever my intended way to measure the Pi Camera was overly complicated, as I was starting to figure. While I was looking to draw some kind of grid and view it at an angle and get help with the whole bunch of mathematical nonsense that produced, all I needed was the distance out and to either side as if following an upper case T. I didn’t even need to calculate the angle proper, because I could just add a cone with the proper dimensions.

The unforeseen challenge in stock for me this week was and in a way still is getting the model to comply. Long story short, Blender wants me to make quality meshes, otherwise it will crash. At least the stress test looks good for the auto recovery feature.

I made several prototype eyes for my camera to peek through. The first one based on the custom model of the Pi Cam had some gunk in there, but when my father was done introducing the razor to it, the piece fit perfectly and when I held it up to the camera, it could see through it perfectly. However, unlike the Blender model, the printed version had a hole where there was supposed to be a thin spot.

I printed up another version, this time on a higher quality and the circuit board bumped back a bit, so far, an extra bit on the camera didn’t need an extra hole I made for it. And that’s where I am now, modifying the hole model, with limited success. At the moment, I’m thinking I can drop some detail I no longer need, rather than keep at coaxing Blender into doing my will for it.

Final Question: Have you ever known exactly what needed to happen and not known what the controls were to make it happen?

Posted on

A New Tool Part 4

Good Morning from my Robotics Lab! This is Shadow_8472, and today, I am recounting my slow adventures in altering a Raspberry Pi case. Let’s get Started.

First off, I did not reach my intended checkpoint of getting a model ready to print, but I am far enough along, I can cover the specifics in next week’s post.

For this week, I finished Blenderguru’s Beginner’s tutorial and the modeling tutorials where he makes an anvil. I did not follow along, but I picked up a bunch of little, refined tips, like how you usually want to always use four vertices per face unless you intend to use it in a game engine that likes triangles. (Before, I had only heard you want to use three or four, but be consistent.)

While trying to organize, I visited this local, informal technology workshop where my father, the guy running it, and I basically repeated the same things to each other until someone drew a picture. From my point of view, I was hearing “You need to make a cone as part of your cutaway,” meanwhile I had already made a cone to accommodate the camera body. It was only after a while that i figured out I needed to make a cone for the light coming in. I did have a major milestone there though, I measured the bottom part of the case with the caliper in millimeters, and the model for it in Blender Units, and it was just off of a 1:1 ratio. I chalked it up to instrumentation failure and disregarded the two extra millimeters.

My project, as of this writing, has a crude model of the Pi camera loaded along with the Pacman ghost’s head by Darren Furniss on myminifactory.com. LINK When building the model, my father and I overestimated the dimensions each time, rounding up to the next millimeter. I want as little of the camera exposed while still having the whole picture clear of the case. I’m still missing information. I have no idea how wide to make the cone. My proposed method of study is to lay the camera flat on a table and somehow plot out the cutoff between visible and invisible.

Final Question: Plotting out the light cone a camera sounds tedious. How would you calculate it?

Privacy Policy