All modern garage door openers have a safety feature: a small light beam to detect objects that might be in the way. Most of the time this feature is unobtrusive working in the background for my safety.

Occasionally, though, the sun would be at an angle that blinds the beam receiver. When the sensor is blinded, the garage door opener defaults to safety and behaves as if there was an obstruction in the door. Great for safety, not great for actually getting the door closed. What we needed was a sunshade.

The tolerance requirements were very relaxed relatively to the other projects. I didn’t even need the precision of a caliper, a ruler was enough to get me in the right ballpark.

I rotated the shape 90 degrees, so that it faced down, to enable easier printing. By doing this the shape could support itself as the 3D printer built up the layers, no need to waste material printing supports. Aligning the object in this manner also resulted in a cleaner inner surface for the tube.

At the time of this project, my 3D printer was loaded with transparent filament. I decided to perform a test print even though a translucent shade would be counterproductive to the goal of shading light. I thought I’d make a few test prints and iterate to the final design as my 3D projects usually do, and load a different filament for the final print.

My plan was foiled by the realization it fit and worked right off the bat. Even though the end result is not opaque to light, I suspect it breaks up enough of the sunlight. If the transparency ever becomes a problem, I can always spray paint the exterior of the object.

Good enough! I declared the project complete and moved on to the next thing on the to-do list.

Update: I’ve printed and installed an opaque replacement.

The “Duck light” project earlier was a lot of fun, crafting an object to be lit with a little LED tea light. I liked the result so much I kept it lit around the clock, which led to the obvious next problem: battery life.

These lights came with a standard CR2032 lithium battery good for 2-3 days of continuous use. Replacement batteries can be found for less than a dollar, but that’s almost as much as the cost of the entire light! I embarked on a project: find a better way to keep my lights glowing.

Online search found some basic details on CR2032. The full power voltage is 3 volts, conveniently a multiple of the ubiquitous AA battery’s 1.5 volt. More interesting, however, is that the quoted minimum voltage is 2 volts. Most AA-powered devices would stop working well before an AA battery drops to 1 volt, which implies that a “spent” AA would still deliver sufficient power for the tea light LED.

With this research in hand, I proceeded to design and 3D-print a small battery tray as simply and inexpensively as possible. Normally an AA battery tray has metal springs to push against the negative end of the battery. My project takes advantage of the fact the 3D printed plastic is flexible, and print a curved arch to provide this holding force.

I need something at each end of the tray to complete the circuit. One end is easy: I pulled the LED component out of the tea light base and used pliers to shape the wires into a Y shape to connect the battery terminals. At the other end, I used a piece of aluminum foil from the kitchen. Normally this is a bad idea because a thin foil of aluminum can’t carry much current, but it should be fine given the extremely low power flow of the LED.

To make the base more presentable, add a cosmetic shell to cover the battery tray and provide support for whatever we want to keep lit, and voila! A small lighted base for any purpose.

I had a pair of AA batteries that had been in my Xbox One wireless controller. I received “battery level low” errors for about a week before the controller refused to turn on at all. Yet these batteries were still powerful enough to light up the LED and keep them lit for many days.

A cheery light powered by batteries that would have otherwise been thrown away. Success!

And now for something with aesthetics as its primary function: A duck light. I started with the battery-powered LED lights imitating little tea light candles. These lights are widely available at very low cost from discount stores and dollar stores. My local 99-cent store sold a pair of lights for 99 cents.

The lights consist of the functional base, incorporating the battery, the switch, and the LED. It sits under the cosmetic shell, which is a cylinder pretending to be a candle with an unconvincing imitation flame above it. A little prying action should be sufficient to separate the shell from the base.

The unremarkable cosmetic shell can go in the trash. Then measure the diameter of the remaining base. Use that as a starting point: Go into Onshape and design a custom shell for that base.

My custom shell project started with a surface that describes a variant of the popular bathtub toy duck. It was not difficult to import the surface data into Onshape, but making use of the shape turned out to be more difficult than anticipated. Onshape surface manipulation tools aren’t robust enough (yet?) to deal with arbitrary surfaces imported from elsewhere. In theory I can use the “thicken” command to turn the surface into a solid, but it and many related operations fail with a generic error message.

After some trial and error I found that the split operation works: Define a large rectangular solid, position it over the duck surface, and split the solid block into two: the duck and its negative. After deleting the negative, I have a solid duck shape.

In theory I can use the Onshape “hollow” tool to hollow out the duck shape, but again I was stymied by the error messages. To work around this problem, I started crafting shapes to manually carve out the interior. It didn’t take terribly long to hollow out the bulk of the duck this way.

After sending the hollowed-out duck to my 3D printer, I was able to mate it with the LED light base and now I have a custom duck-shaped tea light!

The next problem to solve in the kitchen are a pair of oil bottles – sesame oil and chili oil. Conveniently, they are from the same company so they have the same sized bottles. Inconveniently, they stand taller than other items in the kitchen cabinet, blocking views to the back and easily topple over as I reach for nearby items.

I decided it’d be good to have them on the door instead. Pull them out of the clutter. The easy way to do this is to have a shelf on the door. Unfortunately, tall bottles make this complicated: the shelf needs to be deep enough so that the bottles don’t topple over when I open the door, yet not so deep to make the bottles inconvenient to access.

My solution is to start with a shallow and accessible bottom shelf. Above the center of gravity, the bottle will be held by a flexible clip. The clip needs to be strong enough to keep the bottle from toppling when the door is opened while able to give and release the bottle when I want to pull it free. 3D printed plastic can handle the flexibility part, no problem, but the durability is a question mark. The weakest part of a FDM printed part are between the layers. When something breaks it’s almost always at the layer boundary. It’s important to make sure that the design accounts for the strengths and limitations of the manufacturing technique. We accomplish the goal by arranging the features to avoid the sharp corners that magnify the stress of flexing.

Fortunately Onshape has plenty of tools to round out corners and edges. With the help of those tools and some creative intersection across orthogonal axis, the resulting shape looks more fluid and organic than it actually is. I’m pleasantly surprised at how well the appearance looks especially since I was strictly focused on functionality.

After being duly humbled by the complexity of the planetary gears project, I decided to back off a bit and tackle something simpler. While cooking in the kitchen, inspiration struck as I poked around in the cabinets looking for the condiments I wanted: let’s organize this thing.

This is a problem space ideally suited for 3D printing: Low-volume problem solving. Everybody’s kitchen layout is different, starting from the cabinet dimensions to the selection of spices and condiments to how much a person uses each spice in their preferred meals.

Naturally, I quickly dropped into the rabbit hole of devising a grand master plan to completely organize the kitchen cabinets. It took a while before I reminded myself: “Hey, remember when we decided to do something smaller and simpler?”

Right, that. Let’s get back to that.

The first item with immediate usefulness is a way to keep the sugar and salt containers in a way that keeps them accessible, standing above the fray of the other little jars and bottles. The few initial versions focused on building stack-able jar cubicles, but that ran into problems as the dimensions approach the maximum print size of my little printer.

Retreating yet further, I decided the vertical dimension support can be accomplished via some threaded rods and nuts I can buy at Home Depot. I only need to deal with the horizontal dimension – the shelf itself. The threaded rods are the vertical posts, they go through the small holes in each corner of the shelf. The shelf is then held in a particular position by the nuts on each of the rods.

Successfully reducing the problem down to basics gave me a small shelf that is quick to print and solves the problem. No more time-consuming huge cubes, just a small slice of plastic. It’s simple, it’s fast, it works.

If you also want to organize jars 9 cm in diameter, you can find this item in the Onshape public document library under the title “Condiment Shelf”

The current state of the art in consumer home 2D laser printer is that I can expect perfect prints immediately. Take it out of the box, load paper, load toner cartridge, hit print, and out pops a crisp printout.

The current state of the art in consumer home 3D printing is not anywhere near that level of maturity. It took several days of experimentation and many failed prints before I had something that was charitably described as passable.

Example #1: With a laser printer toner cartridge, the user doesn’t need to care about the chemical composition of the toner or the physical attributes of the powder within. The 3D printer counterpart is the plastic filament, and today the user has to know a lot. The user can choose the category of plastic (ABS? PLA? etc.) but the precise chemical composition varies from brand to brand. The user has to adjust the printing temperature to match the plastic. The user also has to keep an eye on the filament diameter because it may vary from the nominal quoted dimension, which impacts the volume of filament being fed into the extruder and thus print quality.

Example #2: With a laser printer paper tray, the user doesn’t need to care about the texture or the thickness of the paper. The 3D printer counterpart is the print bed, and today the user has to know a lot. The bed has to be level relative to the print head movement plane and also spaced appropriately for that important first layer. If it is a heated bed, the user has to specify the proper temperature for the plastic filament. The surface of the print bed has to strike a balance of adhesion. If the extruded plastic can’t adhere well enough, the part would detach mid-print and ruin everything. If it adheres too tightly, the resulting print would be hard to remove from the printer, possibly damaging the printer if you force it.

Because of those and many other variables, it is wise to start with something simple. Something small and fast to print so I can quickly iterate between test prints. Yet complex enough to show if the printer is doing a good job or not hitting the desired dimensions and holding tolerances.

For this, I created a small octagonal solid in Onshape(*). It has straight edges – both aligned with printer axis and not. Two round surfaces, and several horizontal surfaces. One or more features would go bad when the print settings aren’t ideal.

Print, fail, adjust, repeat.

(*) available as a public Onshape document. Log in to Onshape and search under public documents for the name “Octagon test piece”