Topic: Making

Finished "Upstairs" Dividers

2020-09-26 16:12 - Making

I live on the back (away from the street) side of my apartment building. So things tend to be pretty quiet, and there's no street lights outside my window. But there is another building, with a hallway with windows and bright fluorescent lights that never turn off. It's not much, but it's enough to be annoying at night.

The partial screening curtain for my sleeping loft.

So a while back, I got some black curtains and a rod to hang them from (which friction fits between the support beams). This basically solves the problem. They're thin but good enough to block most of the light from outside in the "upstairs" sleeping loft where my bed is. But it does leave a section open. I always wanted to fix that. When I first set this up, I considered continuing the curtains straight across to the wall. that would have divided the hallway a bit too much though.

Making the curtain rod clips. The completed curtain rod clips.

After quite a long time I finally came up with an idea I like. I've got a standard curtain rod, intended to bridge across the top of a window. But this spot is a concrete support beam: not easy to screw into for mounting. The solution was some tiny brackets, with enough surface area to simply hot glue to the wall. One of them ripped the paint/plaster off after a day or so, but that was a week ago and they've held fast since, after being re-glued to the bare surface beneath.

My completed screening curtain, including a dip under the suport beam and a turn around the corner.

First I had to do some sewing, to fit the curtain around the support beam. Then it turns the corner and covers the remaining open area on this side. It's a minor change but a great improvement in feel.

Making My Own 3.5" → 5.25" HDD Bracket

2020-05-12 22:01 - Making

The brackets, fresh out of the 3D printer. The brackets after cleaning up a bit. Test fit on a spare old drive. Installed!

I haven't used my 3D printer in quite a while. This is the time, it's tough to get things these days. I'll save the long story of many failed attempts and tweaks to get it working again, but I just have done that.

I've had an extra drive in my home server for a while, since I upgraded the main set from a three-drive single parity to four-drive double parity setup. And nowhere good to put it. It's the remote backup for my Mom's files, on the server I keep at her place which is itself the remote backup for my own files. It's been awkwardly perched, upside down, on a piece of cardboard. I've got four unused 5.25" bays in that case, so it should go there!

I found a nice, compact design for brackets to fit a 3.5" drive in a 5.25" bay online and printed a set out. My printer makes "hairy" prints, with fine strands everywhere, due (I think?) largely to its design. And at least while I'm using up the ton of free ABS filament I got, bed adhesion is tough so I tend to print with a brim. First step was quickly cleaning up all that cruft, which is shown in the second picture. They're not pretty (I picked fast rather than high quality print settings), but they'll work.

Next, I drilled out all the holes. Half large enough for a screw to fit cleanly through, so they could screw into the drive. The other half exactly the right size to grab the threads of the screws, the outside holes are for holding the whole thing into the case. I did a test fit (the third picture) and it worked well enough, after a little more adjustment with the hole position. Then it was straightforward to pop the drive in a proper location, and screwed down!

In that last picture, you can see one of my main drives, currently tucked into the floppy drive slot, so the mounting holes don't line up well. I might make a second bracket to hold that one, too.

My Automatic Heater Controller (Thermostat)

2020-02-05 21:03 - Making

Lots of New York apartments are actually too hot in the winter. Steam radiators are common, and they don't offer much control. There's strict laws about lower temperature bounds, but none for upper bounds. And most significant: the building usually shares one control everywhere, but the heat reaches different parts of it differently, and the cold seeps in differently.

In my current place, it's also too hot in the winter. I think that uneven-across-the-building issue is the real one for me. I've heard that other parts of the building are too cold. My heat comes from a forced hot water system, which the building controls. I suppose I'm closer to the feed than other apartments. I've only got standard plumbing style cut-off valves. I can totally disable the heat, but then it often gets too cold. I can enable it, but then it often gets too hot. For a few years I've been hoping to make something to help fix this. The video above is my solution!

I actually got a "test valve" some time ago to play with, when starting this project. My test valve didn't work at all for the project, but I lucked out: the test valve's handle is permanently attached, but my real valve's handle is attached with a hex nut, it's removable. The first part of the project was the handle replacement. It's the round smoky plastic bit. It has a hole in the center that's just the right shape (an eight millimeter hole, but with two sides squared off at six millimeters) to turn the valve. It's got eight small holes around the edges and one late addition hole for a screw to hit the valve's end stops.

Those eight holes are for screws, to attach to the large black 3D printed gear. This is a 180-tooth monster built to fit a GT2 timing belt, as are commonly used in 3D printers. It's big for mechanical advantage. I started with a 30 and 60 tooth pulley (for three and six times advantage). They weren't enough so I got a 20 and a 16 tooth gear, and ended up with the 16 tooth gear, for a slightly greater than ten times mechanical advantage. A straight GT2 belt section was cut to the right length, and belt clamps and tensioner springs turn that into exactly the right size belt for this contraption. The big gear is these two parts screwed together for two reasons. First, it would take a long time to 3D print the whole thing as one part. More importantly: the quarter-inch acrylic plastic is strong enough to turn the valve, but a 3D printed part is not!

That's all connecting my big gear to the small pulley on the end of a stepper motor. This is the first real motorized project I've put together myself, and I was not at all confident. When I spotted the uStepper S product on Kickstarter, I knew it was perfect for this. It's a clever combination of stepper driver, Arduino, and hall effect sensor (which uses a simple magnet stuck to the stepper motor's shaft!) to give it closed-loop control abilities.

The stepper is screwed into another acrylic sheet. It's in slotted holes, which gives me some room to adjust the length. This mounting sheet is mostly zip-tied to the copper heating pipes. But it's also screwed down into the floor, through a brace piece of scrap plywood, to keep it in place left/right. Otherwise the tension of the belt would pull it loose!

So there's a simple control loop running on the uStepper, which accepts commands over serial. It's wired into an ESP8266, which has WiFi connectivity. It monitors the temperature sensors I've already got, and sends commands to open and close the valve based on the current temperature. Simple, now that the mechanicals are all there to support it!

I've gotten this working reliably only recently. My problem is the end stops. Even though I have closed loop control, that only gives me relative data about motion, none about absolute position. The uStepper libraries have a convenient "move to end" feature, but it turns out my system is too mushy. I've got tensioner springs on the belt, which can thus stretch a bit. And worse (I think!) the end stop I've got is just a screw in some plastic, and it's longer than the original steel handle part. It flexes a bit when it reaches the end stop, before it pushes hard enough to actually stop the stepper. When it closes (clockwise motion), you can see a big jump backwards as it stops. (There's a smaller one when it stops going the other direction, I believe this to just be the slack from the springs. I never actually open the valve all the way, it's not necessary and why stress the system more than necessary?) The built in "move to end" feature sees that as constant motion: some of it forwards, some of it backwards, but it doesn't distinguish! I had to write my own routine to detect both a lack of forward motion or backwards motion as the end condition, and then the stepper stops turning.

Now I should finally be able to keep myself comfy over the winter! But even more so in the late fall and early spring, when the building has the heat on, but it's not nearly as necessary.

New Bed Light

2019-08-01 22:24 - Making

The prototype light above my bed.

After I built the bedsofa, I rearranged the bed and sleeping area around it. It had to go up against a wall to avoid tipping over when I lean on it. But the head of the bed was previously in open space. When I turned the bed, this made the light there, hanging from the wall, end up at the foot. Not a great way to illuminate the area, like for reading.

For a while, I pointed it at the ceiling and lived with the indirect light. The existing fixture won't work well in the new space that I've got. I've looked for fixtures that would work better, and found nothing pleasing. But I also have this strip of LED lights, which I intended to install in my 3D printer. (And, of course, never quite got around to doing.) It puts out a ton of efficient light, even just a small part of the reel I've got. The picture above is the "prototype", just taped to the wall. It's intended to run from 12V (and I picked that because the 3D printer has ample 12V power available).

In bed, I actually want very subdued lighting. A half meter of that LED strip running at 12V is really brighter than I want. I've got plenty of spare AC adapters lying about, but they're all too high or too low. But I also have some spare DC/DC buck converters! So now I've got a 12V AC adapter, into a buck converter that's infinitely variable, with its output powering the lights. I can tune it to the exact brightness I want. Perfect.

Some aluminum channel turns an LED strip into a nifty light fixture on the cheap.

I recently found this ultra-cheap extruded aluminum channel. Pop an LED strip into it and instant light fixture. I got this V shaped version which mounts at a 45 degree angle. I intend to point it towards the ceiling for primarily indirect light.

3D Printer: Fixed

2019-07-30 18:27 - Making

I got a 3D printer just over 3 years ago. Some months back it stopped working. I've got an OrangePi running OctoPrint to control it. I did a system update of that, and it stopped working. I unhooked everything and tried to figure out why, and failed. And gave up for quite a while.

I've got a thing I want to 3D print, now. So I took another stab. First day, same result: I was trying to set up everything from scratch, but I couldn't get the thing to boot. After switching out every spare power supply and SD card I had, still no dice. Of course, the whole time I wasn't thinking about the cable that carries the power. Turns out that was it. Once I swapped in a different cable, everything was working again. Set up OctoPrint again from scratch, and it's all great.

I just completed a 10mm cube test print, which worked fine. The machine needs a little TLC, it's squeaking a bit as it moves. But it works! Unfortunately, my desired object is too big to produce on my machine. So I'll need to find another way.

The Bedsofa

2019-04-21 13:07 - Making

I posted about this project just over two months (!) ago, around when I was getting started in earnest. That was starting the cushions, which were the "scariest" part, where I've got the least relevant experience. Since then in my weekends and evenings (on and off), with some time for shipping delays and generally enjoying myself otherwise, I've completed the rest.

This post is the story version of how that all went! It will be a little bit out of order so that the story goes well. If you're truly curious, look at the un-adjusted file names in all the images, the dates and times are burned in there and generally represent when the pictured step happened.

Plans

The very first paper plans for the bedsofa.

I just wanted to call out this original paper sketch that I did at the very beginning of the project. I've changed a few things, and it's not to scale, but most of the idea was there from the very beginning.

Cushions

The first bit of cushion piping, and the section of fabric they were cut out from. A closer image of the piping. The first assembled zipper panel, uneven stitches and all.

As previously mentioned, I started by experimenting just a bit with the piping. When I was happy that would work, I did them for real: four long single sections to go around the edges. (Here was one of my first big mistakes: they weren't quite long enough. Three of them got extended; one was already stitched in when I realized, so I've got a small gap. Thankfully at the bottom where it doesn't show much.) Next up was the zipper panels. I'm not sure what exactly I did wrong, but they came out very uneven. Not so much of a mistake as an "apprentice mark", here. You can also see the extreme degree of raveling at the edges of the zipper panel, which plagued the sewing part of this project.

Stitching together the first cushion shell.  Plenty of pins to keep things aligned. All four sides stitched to the front, from the wrong side.
More stitches complete, from the right side things are looking great! The first cushion shell is complete, turned right side out.  Some of the issues become visible.

As hinted in the piping failure, the next step was stitching up the shells for the cushions. This went almost completely as intended. A couple pieces were a bit small, not really enough spare material to hem. I think this is because (or, worse because) upholstery fabric is stronger, with thicker threads. Which don't weave so tightly as a result, and unravel easily. The second issue was sewing up the corners: with that quarter-inch-thick piping in the way, those were very difficult stitches to make. More apprentice marks here: a few corners are perfect, but most are uneven in random directions, just a bit.

To insure against raveling, the seams all got binding tape stitched in. Both cushion shells completed.

Due to the unraveling, I took the time to (order, and) sew in binding tape around all the seams inside the cushions. Things would probably be fine without this extra layer, but it adds peace of mind at least. And another mistake: when stitching them in, I got a bit of the side panel across the top of one cushion. So it's a little narrower, and has an extra unnecessary stitch visible. Ah, well.

A hot-wire cutter jig, to get the cushion foam cut exactly right. The hot-wire cutter makes perfectly straight cuts!
The first cushion, stuffed with the just-cut foam and batting (which is visible behind the cushion). While stuffing, one of the cushion

With only spare material for this project and "junk drawer" items, I put together this hot wire cutter jig. You can see the very rough edge that I hacked out of the foam with a knife, just to get close to the proper size -- my wire cutter has only a few inches of throat. Then, the wire-cut edge: perfectly straight and smooth. With the foam cut out to just the right shape and size, stuffing the cushion shells went very well! Except for one ripped seam I had to repair, a raveled edge which caused a weak stitch. This was repaired with some "fusible bonding web" because I didn't want to re-make the whole thing! You can see one piece of binding material in the corner of this picture, where I knew the edge (and thus stitch) was weak. Apparently I needed a bit more! I ripped out most of this seam, bonded the extra material to it, then re-stitched it.

Structure

The first pass of structure pieces, cut from two by fours. Since these were cut at the office workshop, I had to get creative to transport them home!

With the cushion shells completed, I was confident that I could make this project really work. So I bought a bunch of two-by-fours. These were cut up at the workshop in the office -- a great perk. And then bunched up to roll home by hand cart. Since they were smaller in their cut-up form, this was easier than rolling the raw stock from the store to the office -- thankfully that was only a few blocks.

Scribe, don

I was overconfident. The complex angled pieces did not come out right in that first batch of cuts, going only by measurements. I got lucky here in that I planned for eight foot boards, but ended up with ten footers. Each had just enough extra slack that I got my four main five-foot-long boards cut out of only two of them. This left an extra unused board, just enough material to re-cut these pieces.

For this second try, instead of cutting the piece to fixed measurements, I clamped up the rest of the pieces in place and scribed out the exact shape I needed, then cut from that template. These didn't end up perfect, but A) good enough and B) that's a small theme of this project.

The first step in assembling the structure was the frame of the very back edge. Second, the front-to-back pieces at the bottom edge are attached.
The rest of the front edge is attached, with some face screws and some pocket screws. Finally the angled uprights span the front to back, and present the recline angle for the seat backs.

At home, the structure is all screwed together. Pocket holes are used liberally where possible, and some simple butt joints as well. The back was assembled first, then pieces were screwed into that. Then the shorter front section onto that. This was the main shape that was templated above, so the angled sections, support for the back rest, were added and the main structure was complete!

The first seat back is clamped into place, to scribe exactly where it needs to be cut to match the structure. With both seat backs cut to fit, they The extra batting material covers the (now completed) structure.  This adds a little strength to the open sections and a little softness to the hard edges..

With the main structure complete, the next task was to attach the seat backs. These were rough cut from plywood, then marked and clamped in place. The cuts were scribed to the actual structure: nothing came out perfectly square or perfectly to plan, but this let me get the pieces cut to match! The top and bottom cut are angled to match the recline, so they end up with "flat" edges relative to everything else, which is nice.

On recommendation of a coworker that I've been chatting with about the project, especially the sewing bits, I got some batting to wrap the cushion foam in. The smallest unit was quite large. I had been considering some sort of foam layer to soften the edges of the structure with. All that spare batting took the role! In hindsight, I should have chamfered a few of the wooden corners before this, but it's worked out well enough overall.

Upholstery

The bottom was upholstered first.

The upholstery step was also a new skill to execute. It's done with the same exact fabric as the cushions. My original idea was a solid color, to make both the cushions and the upholstery easier: no opportunity for mistakes laying out the pattern. I ended up with a pattern. It went almost completely fine. The entire lower section, beneath the seats, is one wide piece. This went well, except that the sides stretched a bit unevenly, leaving some warp to the pattern there. There's also a little spare material wrapped around the spots I expected to be tricky: in case I completely miss something, this lower layer (rather than the white batting) is what will peek through.

A cardboard strip ensures a crisp upholstered edge at the bottom of the seat back. A metal tack strip helps bridge the otherwise empty gap between wooden structure, when crossing from front to back.

Next was the seat backs. They went quite well overall, except due to the recline angle, the pattern is angled next to them. That's fine. The bottom edge is tacked in with a cardboard strip which keeps that edge nice and straight. Some metal tack strips bridge the empty space front to back over a gap where there's no wood structure, holding a clean edge. The material is folded up over that, then wrapped around the structure and stapled from the back, leaving a nice surface on the front and sides.

The bulk of the upholstery is complete, and looks snazzy! Upholstery complete, side view.

Clean. The last piece to upholster is the bridge across the top. I took two tries at this, not pictured. The first was only tacked at the bottom and wrapped around, a bit too loose. So I took the folding metal clamps from my upholstery tack set: with the inside tacked across the bottom, this holds the left and right edges in place by being tacked in underneath, folding the material over, then bending the metal down to hold it all in place. With the remaining edge tacked again from the bottom.

Preparing to upholster the back (and bottom) with dust cover material. One side and the middle back is now upholstered. Dust cover upholstery completed.

The back will be slightly visible, as the wall it will be resting against is only partial, with the sleeping loft looking out from above on both sides. So the back (and bottom) is being covered in a black cambric dust cover fabric. It's got a small corner folded back, for the electrical cord (read ahead!) to stick out of. Like the rest of this project, it's got small issues. Not very visible in the far side of this low-lighting picture is a fair deal of bunching (at the left side when looking at the back). Which of course ended up being the more visible side. I might go back and re-touch that.

Shelves

Fitting the lower shelf on its supports, not yet finished.

With the main upholstery done, the shelves were the only significant remaining piece. Like with the seat backs, nothing is perfectly square here. I used "story sticks" to measure the front and back widths, they were a sixteenth to an eighth of an inch different. Then I cut out blanks, with the front edge angled again to match the recline, too deep on purpose. Once they generally fit, with the front edge lined up nicely, the back edge was marked to match the structure and cut square.

Installing the upper shelf, with plenty of clamps and wedges.

Both shelves are held in place with half-wide two by four pieces screwed into the main structure, which they're also screwed into from below. The top shelf was cut a little wide, so I used some scraps of wood to stretch the opening a bit. This made it easier to insert the shelf without stretching the fabric too much. For the bottom and top, it was a tricky operation of putting the shelf in the right place, so the support pieces could be clamped in place. With those clamps holding, verify the placement is good with a level. Then screw in the support pieces, and screw the shelf to the supports from underneath.

The lower shelf is flush with the main structure so its bottom side and supports are invisible. The upper shelf of course is visible from all sides, as are its support pieces. So when finishing, the top shelf was finished on all sides, as were its support pieces to match. Both the two by fours and the plywood were near paper white, which didn't look super nice next to the relatively dark blue fabric. I used some Minwax "Polyshades" which I already had from a project a few years ago. This is a stain and (polyurethane) finish in one. I probably would have done separate if I was buying specific for this project, but this worked out pretty well. I couldn't choose the color, because I was using the spare I already had: "Mission Oak", which is quite dark.

Both shelves, after finishing, are installed.

I'd change one thing if I could go back, though: I did the smaller top shelf first, and I brushed on the finish (like the instructions said to!). This gave a very thick and dark coat. For the second shelf, I wiped the finish on on with a rag. This gave much thinner and finer coats, and a lighter color I would have likely preferred. It took eight hours for each coat to dry, but I ended up putting four coats on the lower shelf, to get it to a depth of color to match the already finished top shelf. I'd have done only two or three wiped-on coats on both, if I knew how that would end up ahead of time.

Electrical

The kitchen hutch which inspired the electrical outlet. Notice the electrical outlet at the back corner of this hutch.

This is going up in my sleeping loft. There's only two sides of this loft which have walls this can rest against (for support), and both of them have electrical outlets. Whichever one this goes in front of I'd like to use: I plug in various eBook readers, tablets, game systems, etc. to charge. In my first apartment, I had a nice table/hutch in the kitchen: It had a small shelf above and more importantly an electrical outlet built into the surface, with a cord to plug into the wall. It made a convenient place to plug in a mixer or other appliance, while cooking. Above you can see a crowded/messy picture from when I was near packed up to move out, and a closer in picture of the outlet in the surface. I decided to do something similar to that for this project.

Wiring up the electrical outlets and switch. The outlets are installed in the junction box, with a matching hole cut in the shelf.

The bedsofa will block my outlet, but it will have its own replacement outlet built in. I splurged here and I got an outlet with USB ports also built-in, and a switch to control things. The electrical box I got was designed (as far as I can tell) to fit through half inch drywall, but I'm putting it through three quarter inch plywood, so I made up some shims from some old quarter inch wood stock to fill the gap, which helped everything screw down tightly and line up nicely.

I made a small accident here: I've got a two-gang box. The first gang is a switch/single outlet, while the second gang is two outlets plus two USB charging ports. I wired it up with the intention to have the switch disable everything (and any possible vampire power). But what I actually did is just switch the second outlet. The single outlet with the switch is permanently on. It wasn't intentional, but this is nice and flexible, so I'm keeping it.

The Glamour

Completed, close up. Installed! Installed, as viewed from the stairs when approaching.

Here it is, completely in place. When it was being assembled on my coffee table, err...work bench, I realized it wasn't quite square, it would wobble a bit. I got adjustable screw in feet, to make it possible to leave it perfectly stable and flat. In addition, there's two of these feet sticking out the back of the top. These rest against the wall, so that it remains stable and upright when I sit back on it.

Cost

Look at this as either a passion project or explanation of why furniture is expensive. Or both. Some of this, especially the wood, is down to Manhattan prices. I've rounded things to the nearest dollar after tax, just to make the accounting easier. Either way, I spent:

Item Cost Where
Structure
Two by fours (six, 10 foot each) $58 Prince Lumber (Local)
Baltic birch plywood (3/4 inch, 5 by 5 foot) $57 Prince Lumber (Local)
Stain/Finish $0 the "junk" pile
Subtotal $115
Upholstery and Cushions
Fabric (55" by 7 yards) $56 eBay
Zipper $13 Jet
Cambric (dust cover) $12 Jet
Welt cord (too big, too short) $7 eBay
Welt cord (3mm x 50yd) $9 Jet
Cushion foam (3x24x72") $40 Amazon
Dacron Batting (48" x 5yd) $24 Amazon
Binding Tape $10 Amazon
Tack Strip Bundle $25 Amazon
Subtotal $196
Misc
Furniture levelers $11 Amazon
Screws $9 Home Depot
#000 Steel Wool $5 Home Depot
Subtotal $25
Electrical
Power strip (for cord only) $5 Home Depot
Electrical box $7 Home Depot
Face plate $3 Home Depot
Switch/outlet $13 Home Depot
Outlet w/ USB $25 Home Depot
Wire nuts $0 the "junk" pile
Electrical cable $0 the "junk" pile
Subtotal $53
Tools
Countersink bits $12 Jet
Bar Clamp Set $22 Home Depot
Subtotal $34

For a grand total of $389, $423 if you include the tools that I bought specifically for this project. Phew.

I did a lot more impulse buying and splurging than I normally would, while working on this. But not only is it a useful durable piece of furniture that I'll keep, it was also essentially entertainment budget: I got to flex several old and new making skills.

I used most of the screws. Several of the upholstery pieces were mostly used. The zipper was just barely, as was the welt cord. In both cases, these were the most economical choices, anyway. I used only a tiny bit of the batting (around the foam, in the cushions). I've also got almost half of the baltic birch plywood left, which should easily turn into some new project in the future!

Quick T-Bevel

2019-04-02 18:52 - Making

Front view. Back view.

My bed sofa project is progressing nicely. I expect to put together a detailed post, once it's complete. Over the weekend I picked up some nice plywood, for the seat backs and center shelves. Cutting those pieces right is challenging. I've got the main frame assembled, at home. I've got tools, at the shop at work. I want to transport as little as possible. And I also have some angles to cut, and hopefully get just right.

I've seen one of these before, probably on This Old House, and that's the article I found when I went looking for the name of the thing. I decided to make one quickly today. Laser cut a shape that allows me to match angles like the commercial equivalents. Tighten the nut to just lock it down, then push it into the angle to squeeze it perfectly flush. Then just scribe the same line onto the real material. (After tracing it onto a piece of paper, to measure more easily, it seems I'm at about 22.5°. I was aiming for 20°, but shifted some of my measurements around. And some of the cuts were probably not perfectly to plan!)

In this case, I'm trying to cut the top and bottom of the seat back, which is an angled piece. So that the cuts are level, flush with the neighboring pieces of the frame. I've got a jig saw at home, which I've used to divide the pieces down to the smallest possible size, for transport. The band saw in the shop has a tilting table. I can match that table to this angle, and get exactly the cut I want. The only challenge will be getting the right height, after cutting this tiny bit off.

I could have spent about ten bucks to buy one of these, but it was much nicer to make it! This was all spare materials except $0.33 for the thumb screw at a local hardware store on the way home! Access to a laser cutter really helped.

The Bed Sofa Begins

2019-02-13 22:39 - Making

I've got nice high ceilings in my apartment. And at one end a raised sleeping loft. There's only three or four feet up there, but it's plenty of room to lie down in. Except the bed is actually just a mattress on the "floor". I've made it work so far.

My bed, in my sleeping loft.

But, technically, it's just a mattress on the floor. There isn't the height for a "real" bed. I've got a chair next to the bed, but I don't end up using it much. I'd rather sit up in bed. I thought about it for a while, and I had an idea.

The design for the bed sofa.

It's not at all unusual to take a sofa, add a mattress, and call it a sofa bed. So why can't I take a mattress, add a sofa (back) and call it a bed sofa? I can build in a couple cushions at a gentle recline, a shelf to hold an alarm clock and a few books, and sit up comfortably in bed! Read a book, under the covers, then just lie down when I'm ready to sleep. This would make me happy. And it's a nice project with some opportunity for design (done), carpentry (I can handle that), and upholstery (oooh, new skill to learn!).

The design for the bed sofa, seen from the back.

The construction is primarily two-by-fours. The seat backs might be plywood, but might be zig zag springs. Which are normally used for seats, but I wonder if I'd like that bit of give to the back. Some plywood or wide solid boards will make the shelves, and the whole surface (except the shelves, I think) will be covered in upholstery fabric. Then I make some custom cushions, with the same fabric over foam. Voila!

It's the cushions that are the exciting bit. I can sew. I think. This will be a special new challenge. I want the edges to have piping like real upholstery, so I need to figure out how to do that. Time for experimentation!

Raw materials for my first attempt at piping. Result of my first attempt at piping.

My bed sheets and cover are dark blue. I was looking for some fabric that would go well. Expecting a solid color (because the sewing would be easier, with no pattern to worry about lining up). And clearly from the design I was thinking grey might go well, but I found this blue fabric with a geometric pattern that really appealed to me. So I got several yards of it. Plus some "welt cord". The idea is to sew a tight loop of fabric around the cord, then you've got a matching "pipe" shape to sew into the corner seams, and it looks nice. So I gave it a shot. This was a quick and dirty first attempt, which turned out quite well except for not getting a very straight seam.

One test piped upholstery seam.

Then I sewed that up into a seam. I got one of the pieces inside out, but for this simple test that's fine! This is sub-optimal in a few small ways, and I think I know how to improve it. Can't ask for much more! Hung over the edge of the table to roughly approximate the real shape, it's even serviceably straight, despite putting almost no effort in there at all. A couple more practice runs and I should be ready to try my hand on a real cushion. If that goes well, it's time to buy foam and two by fours!

Retro Duo Portable Repair

2019-02-05 22:58 - Making

The Retro Duo Portable, opened. Close up of the repair.  Note the indentations in the card.

The Retro Duo Portable is the portable version of Retro-Bit's clone consoles, which play original game cartridges. A while back I rescued one from the trash. It didn't (quite) work. It could play games, but the screen constantly flickered. I had plenty of early ideas, and for the past few weeks I've spent an hour here and there on evenings and weekends trying to repair it.

One of the first things I did was just open it, to try to see what was going on inside. I don't remember specifically what I tried first, but it was minor. I tested the system again before fully re-assembling, and voila! It worked great! So I reassembled it and ... it wasn't working again. After a couple experiments, I found that if I pushed on the front, between the face buttons and the screen, with modest pressure (in fact, pushing the buttons themselves could trigger the failure as well) then the screen would start flickering. One of the screws that holds the thing together would, itself, apply this same pressure.

With it "working" (and open) I could confirm that really what's happening is a constant trigger of the "contrast" (brightness, really) button's control. In fact, if you hold that button down, it stops. Inside, there is a weak pull-up resistor on a signal line, and pressing the button closes a switch which (strongly) shorts that line to ground. The system triggers on the change of the signal, and somehow only when being pressed, some other signal line was leaking into the brightness control, causing constant and repeated changes of value, which it interpreted as constant pushes of the contrast button.

The first thing I tried was liberal application of tape (kapton and "electrical") to prevent shorts. In the close up picture you can still see a few pieces, which weren't worth removing now that they're in place. I tried all sorts of clever things with the electronics to try to isolate exactly where the failure is coming from, and eliminate it. None of these attempts helped at all. Somewhat in desperation, with no reason to believe it would help — but I was hoping for some sort of structural, rather than electrical, support — I stuck a bit of card inside. Especially in the second close up picture, you can see that there's one spot that it's pinched enough to leave marks on the card. (And the same thing in a second spot, after trimming and rotating the card to fit better, without blocking any of the screws.) Some thin kapton tape (and, I think, a layer of electrical tape on the other side during one try) just wasn't enough. But this card in this location separates or supports something in the right way, and it's all working again! Perhaps with use it will wear down? For now, it's nice to be repaired.

I could buy one of these brand new for around $80. But now, it will always be that one I rescued from the trash, and fixed up.