After seeing the simple Automatic Fish Feeder on Thingiverse, I immediately ordered the required parts and set about modifying the design for my purposes.
I liked this particular design, as we only have a 2 bettas in 2 bowls, and we need to ensure only a couple of very tiny pellets drop with each feeding. I did want to make a few changes. It was not clear how the motor was controlled in the original design – I wanted to use an optical slot sensor to detect when to start and stop the rotating disc.
With OpenSCAD and Inkscape, I modified the original design. I added slots to the rotating disc, which could be detected by the slot sensor, and modified the support to suit my fish bowl.
Parts and Assembly Notes
9V DC power supply
Optical Slot Sensor (I used an Omron EESX1002-W3A – I just picked one at random from my local electronics store)
It took some code tweaking to get the disc to stop at every hole. I couldn’t control the speed of the motor with pulse width modulation – perhaps because it’s geared, or there was too much friction, it just didn’t move unless I gave it the top speed. I settled moving the disc in small increments, checking the measurement from the slot sensor, repeating until it sensed it was in the right position.
Once built, send a ‘1’ over the serial port to the Arduino, and it will advance the rotating disc to the hole.
A while ago, my daughter and I built an outhouse out of Popsicle sticks and a cereal box. I didn’t think anything of it at the time, but she held on to it and kept it alongside her toys. She even brought it to school one day when she had to present a craft she had made.
Lego Friends sets (bakery, amusement park, riding camp, etc) tend to feature something else missing from boys’ sets: a loo. The boys don’t care, the girls’ pragmatism demanded it.
I realized that her Lego Friends sets had washrooms, but her Little Critters house did not. I asked her about it – and what I saw as a fun project was actually addressing a critical need for her Little Critters.
This weekend, we set about modernizing the facilities. We printed out a toilet we found on Thingiverse, and now her Little Critters have a modern toilet.
In the car, I like to use my phone for playing podcasts and directions. My work phone was recently upgraded, and I was looking for a practical way to mount it.
As cars are kept for years, and phones change regularly, I didn’t want:
anything that used adhesives (they never come off!)
anything that blocks vents
The neatest design I’ve seen so far is a steering column mount on Thingiverse, which I had been thinking of modifying for my phone. As my car has a two-tiered dashboard, I thought I would just create a dock that fit my phone in the lower tier.
I prototyped the dock with pink insulation foam, intending to model and then 3D print the finalized design.
After using the prototype for a week, I realized a 3D printed dock was overkill. The phone pretty much stood up by itself on the dashboard, without the dock, so long as I wasn’t driving on ramps well over the speed limit.
I just needed something to provide a little friction, to stop the phone from slipping around. I ended up sacrificing a beloved mouse pad.
I found a design for a Diesel engine on Thingiverse by Nick Randall – I decided that his trucks and wheels would make an excellent base for my train, as he had a tested design with the right dimensions.
The Toronto Public Library has a 2 hour limit on 3D print jobs. To work within this limitation, I printed the design at low resolution over three sessions. The body was printed in two sessions, and glued together with Krazy Glue (cyanoacrylate). In one of the sessions, a different filament was used. The final toy was painted and assembled with screws.
I learned a few more things about 3D printing, design in general, and sharing online.
Parts printed with PLA material can be glued together with Krazy Glue
In this instance, there is a visible gap. The parts were printed with different filament, and as a result, the parts didn’t align exactly. The output from one of the print jobs warped. When laid flat, the middle was probably 2 to 3 mm above the surface
As would be expected, detail is lost when printing at low resolution
When designing a model for printing on 3D printers, the limitation of not being able to print in mid-air must be considered. Although printing with supports is a solution, it leaves a less-than-perfect surface. It would be interesting to learn how more experienced designers work around this issue. It would also be interesting to try a 3D printer capable of using a dissolvable support filament.
A model printed with PLA can be painted with Testor’s Enamel
The library is a great place to learn about 3D printing, and print small parts. It is less expensive than other places – a two hour print job costs about $6. For my next project, however, I would probably look at other alternatives without these limitations. I think the library has probably achieved a good compromise, making a technology available to anyone with interest to learn and a library card, but definitely not offering a service which would compete with commercial offerings.
When I thought about 3D printing, I though about the physical realization of an object. In reality, there are many things that must be considered when designing anything physical, and 3D printing is not the solution to all of them. This is evident even in the simplest of designs, such as this one, where metal screws are used to fasten parts and enable movement.
This model was designed to scale – this might be appropriate for a scale model, but the train looks very long relative to the other wooden trains on the track. Many of the features, such as the lights, windows, and doors, are very small. If I were to design another toy train, I would exaggerate features, and would not design to scale. George’s Trains, a local model rail hobby store, apparently stocks a wooden subway train that follows these principles and appears to be a much better toy.
Finally, it has been fun posting and sharing my designs on Thingiverse. Although I have accounts on other sites with social-network type features, this is the first time I’ve posted anything. It is fun to have an forum to share my work, and it’s great feeling to see that people have looked at my design and clicked “like” – recognition for someone having fun with basic skills, practising a hobby.
I haven’t worked in 3D at all before, and I was looking for a simple project.
As with the Brio/Duplo wagon, I was thinking about what was within my ability, and not commercially available. I decided I would try to build a custom tire valve stem cap with my daughters’ school logo (a polar bear).
Looking at freely available 3D modelling tools, I checked out Blender and OpenSCAD. OpenSCAD seemed to be simple for someone starting out with designs built out of basic shapes.
I converted the bitmap logo I had to a vector drawing using Inkscape‘s “Trace Bitmap” feature. Following an Instructables tutorial, I exported the bear’s outline and features to a DXF file, which can be imported into OpenSCAD. I encountered number of difficulties (it has been a while since I completed the design – I can’t remember which issues, specifically, I encountered). I tried again, with great results, using the Inkscape OpenSCAD export plug-in.
I merged the bear with a cap designed by Dan Ujvari, and printed it at the Toronto Public Library’s innovation lab. I used a black permanent marker to highlight the bear’s details after printing.
It was interesting to learn that even with a simple project as this one, there are limitations to 3D printing. It was almost impossible to remove the support material on the reverse side, as the bear is narrower than the cap. If I were to refine the design, I would make the bear the same width as the cap. I definitely have more to learn about successfully designing an object around the limitations of current 3D printers.
I have been excited about the potential for 3D printing for quite some time.
Shortly after our local library acquired a couple 3D printers, I took the mandatory course, where we were taught the two primary rules of printing at the library:
Rule #1) Don’t touch the heating element
Rule #2) Don’t print guns
Course completed, I started to think about applications. What can’t you just buy, what makes sense to print?
The idea of combining Duplo and Brio seemed like a great idea – I was thinking of an elaborate track with bridges over bridges, and Duplo seemed almost perfect for the job. What I really wanted was a piece with a wooden train (Brio) top, and Duplo bottom.
A quick search revealed that I wasn’t the first person to think about this, someone had already designed a Duplo/Brio bridge support system. Looking into this further, and loading these parts into 3D printing software revealed that each segment would take about 2 hours to print – the maximum time allowed on the library’s printer. Given that a simple bridge would require at least four segments, I looked for alternate ideas and stumbled across the Duplo/Brio wagon.
I downloaded the file, went to the library, and printed it out. 83 minutes later, my train was completed. I attached the wheels to the body with paper clips, and glued fridge magnets to the ends for the couplings. I was quite pleased with the end product (see photo). The library charged just under $5 for the printing time, which is about what a train car costs from a local toy store.
Taking this idea further, I thought I may try to design my own toy 3D printed TTC subway or street car for wooden train tracks. I have occasionally seen them available commercially, but they are generally hard to come by.
My personal brain dump, Opinions, Projects, Toronto