A 3D printed cat treat dispenser on a table with a laptop in the background and with a treat in it's tray and a cat on the left about to eat the treat.

Local IOT Cat Treat Dispenser

November 22, 2022 by Abe Connelly 9 Comments

[MostElectronics], like many of us, loves cats, and so wanted to make an internet connected treat dispenser for their most beloved. The result is an ingenious 3D printed mechanism connected to a Raspberry Pi that’s able to serve treats through a locally run web application.

From the software side, the Raspberry Pi uses a RESTful API that one can connect to through a static IP. The API is implemented as a Python Flask application running under a stand alone web server Python script. The web application itself keeps track of the number of treats left and provides a simple interface to dispense treats at the operators leisure. The RpiMotorLib Python library is used to control a 28BYJ-48 stepper motor through its ULN2003 controller module, which is used to rotate the inside shaft of the treat dispenser.

The mechanism to dispense treats is a stacked, compartmentalized drum, with two drum layers for food compartments that turn to drop treats. The bottom drum dispenses treats through a chute connected to the tray for the cat, leaving an empty compartment that the top drum can replenish by dropping its treats into through a staggered opening. Each compartmentalized treat drum layer provides 11 treats, allowing for a total of 22 treats with two layers stacked on top of each other. One could imagine extending the treat dispenser to include more drum layers by adding even more layers.

Source code is available on GitHub and the STL files for the dispenser are available on Thingiverse. We’ve seen cat electronic feeders before, sometimes with escalating consequences that shake us to our core and leave us questioning our superiority.

Video after the break!

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Move Aside Planar, I’m Slicing My Cone Way

November 21, 2022 by Matthew Carlson 12 Comments

Fleetwood Mac puns aside, very little has changed about how we “slice” models for printers in the last 30 years. However, [Stefan Hermann] of CNC Kitchen has a demo that tries to change all that by slicing conically.

For the uninitiated in the dark arts of printing in the third dimension, the canonical definition of non-conical slicing has been to bisect the model at layer height intervals and generate the perimeter and the infill, then output that as g-code. This is easy to implement mathematically and works reasonably well, except when you have overhangs of more than about 60 degrees on most printers. The idea of slicing in a cone rather than a plane isn’t entirely novel as we previously covered RotBot, which offers a vertical axis of rotation and a print head at 45 degrees. What is extraordinary is that the technique [Stefan] walks you through is done with a stock printer without a complex 45-degree tilt and is a software modification rather than a hardware tweak.

[Stefan] references earlier work done by [Michael Wüthrich] of ZHAW School of Engineering, who wrote some scripts that apply the transformation. The slicer is SuperSlicer, a fork of the PrusaSlicer, which is itself a fork of slic3r. The modified g-code is exported and can be sent to a printer of your choice. He even has a link to a pre-sliced model to try it out.

Of course, different printers have different clearance levels, but the Prusa Mini he uses has 16 degrees of clearance with the sensor pushed up. The code is on GitHub. It’s fascinating to note how all these techniques and forks interact and build off each other. Whether tilted slices, conical slices, or something else ultimately becomes the de facto standard, we’re looking forward to more options for slicing.

Video after the break.

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New Part Day: Exotic Filament For RF Dielectric Structures

November 20, 2022 by Jenny List 10 Comments

The world of microwave RF design appears to the uninitiated to be full of unimaginably exotic devices, as engineers harness the laws of physics to tame radio signals to their will. Among the weapons in their arsenal are materials of known dielectric properties, from which can be made structures with the desired effects on RF that encounters them. This has traditionally been a difficult and expensive process, but it’s one now made much easier by the availability of 3D printer filaments with a range of known dielectric values.

It’s best to think of the structures which can be designed using these materials as analagous to Fresnel lenses we’re all used to in the light domain. The example piece given by Microwave Journal is a metasurface for use in a steerable antenna, something that would be a much more difficult piece of work by more traditional means.

Normally when we inform you of a new special filament we’d expect it to be more costly than standard PLA, but this filament is in a class of its own at 275 euros per kilogram. So the interest for most readers will probably be more in the technology than the expectation of use, but even then we can see that there will still be microwave experimenters in our range who might be tempted by its unique properties. We look forward to what is developed using it.

Via Microwave Journal. Thanks to [Eric Mockler] for the tip!

Brainstorming

November 19, 2022 by Elliot Williams 5 Comments

One of the best things about hanging out with other hackers is the freewheeling brainstorming sessions that tend to occur. Case in point: I was at the Electronica trade fair and ended up hanging out with [Stephen Hawes] and [Lucian Chapar], two of the folks behind the LumenPnP open-source pick and place machine that we’ve covered a fair number of times in the past.

Among many cool features, it has a camera mounted on the parts-moving head to find the fiducial markings on the PCB. But of course, this mean a camera mounted to an almost general purpose two-axis gantry, and that sent the geeks’ minds spinning. [Stephen] was talking about how easy it would be to turn into a photo-stitching macrophotography rig, which could yield amazingly high resolution photos.

Meanwhile [Lucian] and I were thinking about how similar this gantry was to a 3D printer, and [Lucian] asked why 3D printers don’t come with cameras mounted on the hot ends. He’d even shopped this idea around at the East Coast Reprap Festival and gotten some people excited about it.

So here’s the idea: computer vision near extruder gives you real-time process control. You could use it to home the nozzle in Z. You could use it to tell when the filament has run out, or the steppers have skipped steps. If you had it really refined, you could use it to compensate other printing defects. In short, it would be a simple hardware addition that would open up a universe of computer-vision software improvements, and best of all, it’s easy enough for the home gamer to do – you’d probably only need a 3D printer.

Now I’ve shared the brainstorm with you. Hope it inspires some DIY 3DP innovation, or at least encourages you to brainstorm along below.

Madness Or Genius? FDM Printing With Resin

November 17, 2022 by Al Williams 29 Comments

We aren’t sure what made him think of it, but [Proper Printing] decided to make an FDM printer lay down resin instead of filament. Why? We still aren’t sure, but we admire the effort nonetheless. In principle, extruding resin shouldn’t be much different than other liquid things you print like icing or concrete. Then you’d need to UV-cure the viscous liquid quickly. In fact, they wound up making up a paste-like resin using several chemicals and a filler.

Armed with the paste, it would seem like the big obstacles would be over. Instead of part cooling fans, the printer now has two laser heads focused on the print area. Printing in vase mode avoids some problems, but the first few attempts were not very successful.

With a bit of perseverance, the setup did work — for a while. More fine tuning got acceptable results. However, he eventually changed the filler material and got a passable Benchy to print. Nothing to be proud of, but recognizable. Honestly, we were surprised that the laser’s didn’t cure the material still inside the nozzle and cause terrible clogs.

Why put this much effort into doing this? We have no idea. Should you try it? Probably not. Of course, being able to print a paste has its own value. Perhaps delivering glue or solder paste, for example. But you generally won’t need to make tall prints with that kind of material. Then again, we’ve never been opposed to doing something “just because.”

After all, why make a musical instrument out of a Game Boy? Why make a modem with tin cans? You might as well extrude resin.

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Better Sheet Metal Parts With Chemistry

November 16, 2022 by Al Williams 7 Comments

[Applied Science] wanted to make some metal parts with a lot of holes. A service provider charged high tooling costs, so he decided to create his own parts using photochemical machining. The process is a lot like creating PC boards, but, of course, there are some differences. You can see the video of the results, below.

Some of the parts could be made in different ways like water jet cutting or even stamping. However, some things — like custom screens — are only really feasible to do with a chemical process like this.

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3D Printer Z Sensor Claims 0.01 Mm Resolution

November 14, 2022 by Al Williams 54 Comments

Early 3D printers usually had a microswitch that let you know when the Z axis was at the zero point. There was usually an adjustment screw so you could tune for just the right layer height. But these days, you most often see some sort of sensor. There are inductive sensors that work with a metal bed and a few other styles, as well. However, the most common is the “BL touch” style sensor that drops a probe below the nozzle level, measures, and then retracts the probe. However, nearly all of these sensors work by detecting a certain height over the bed and that’s it.

A new probe called BDsensor is inductive but can read the height over the bed in real time. According to information from the developer, it achieves a resolution of 0.01 mm and a repeatability of +/- 0.005mm. We don’t know if that’s true or not, but being able to take real-time soundings of the nozzle height leads to some interesting possibilities such as real-time adjustments of Z height, as seen in the video below.

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