pet

40 Articles

Open Source Tracker Keeps An Eye On Furry Friends

September 19, 2023 by 49 Comments

Most of the time, you’ll know where your cats are — asleep on the bed about 23.5 hours a day and eating or pooping the rest of the time. But some cats are more active than others, so there’s commercial options for those who want to keep tabs on their pet. Unfortunately, [Sahas Chitlange] didn’t like any of them, so he designed and built his own open source version: FindMyCat.io.

The system is in two parts: a module that fits onto a cat collar, and a home station that, well, stays at home. It offers a variety of tracking modes. In home mode, the home station signals the collar every 10 seconds, which stays in a deep sleep most of the time. If the collar doesn’t get a signal from the home station, it switches to ping mode, where it will wait for a signal from the FindMyCat over the LTE-M connection and report its location.

Finally, the app can set the collar to Lost Kitteh mode, where the collar will send a location to the app every seven minutes or thirty seconds. The collar also supports a direction-finding feature, using the ultra wideband (UWB) feature of recent Apple iPhones to point you in the direction and distance of the tracked cat.

The collar is built around a Nordic Semiconductor NRF-9160, a System in a Package (SiP) that does most of the heavy lifting as it includes GPS, an LTE-M modem, and an ARM processor. One interesting feature here: [Sahas] doesn’t make his antennas on the PCB, but instead uses an Ignion NN03-310, an off-the-shelf antenna that is already qualified for LTE-M use. That means this system can be connected to almost any LTE-M network without getting yelled at for using unqualified hardware and making the local cell towers explode.

The collar also includes a DWM3001CDK ultrawideband (UWB) module used for the locator feature. The accompanying app uses this and Apple’s UWB support to show the user which direction the cat is in, and how far away it is. The app isn’t in the Apple App Store yet, so you’ll need to sign up for an Apple Developer account to use it. We’d love to hear from anyone who takes it for a test drive with their own pet.

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Inside The PET Keyboard

August 8, 2023 by 10 Comments

These days, you have a certain expectation for computer keys on a keyboard. Of course, there are variations and proponents of different mechanisms and noise levels. However, back in the late part of the 20th century, it was a different world. Computers came with a bewildering and sometimes befuddling array of keyboards. Since the IBM Selectric was the king of typewriters, we assumed the IBM PC keyboard would be spectacular, but it wasn’t. The PC Jr was even worse! Atari experimented with flat keyboards to save costs, and many computers had keys more reminiscent of calculator keys than you would imagine. The market voted. In general, a keyboard that wasn’t really a keyboard was the kiss of death for a computer. Case in point: the Commodore PET with its infamous chicklet keyboard, which gets a detailed examination in a recent post from [Norbert Landsteiner].

The PET keyboard gets some bad rap due to software limitations. Because of this, some games would use their own scan routines, and [Norbert] has worked on emulation able to accommodate software that wants to read the hardware directly. The resulting insights into the old keyboard is very interesting. For example, you can press more than one key at once. The result? The answer to that question takes up about half the post.

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Building A MiniPET Is Better With Friends

July 17, 2023 by 4 Comments

[Taylor and Amy] love taking on retro computer projects. This week they’re building a MiniPET from Tynemouth and The Future is 8 Bit.  It’s a pretty awesome kit which sadly isn’t available anymore. Taylor bought one of the last ones as part of a charity sale at the 2023 Vintage Computer Festival Southwest.

If you haven’t seen their YouTube channel yet, check it out! The two have been best friends since 1984. Their channel has just the right mix of education and comedy, with pacing fast enough to keep things interesting. It’s really refreshing to see two people enjoying a project together.

The MiniPET is of course a reproduction of the hardware in the Commodore PET, the machine which predated the VIC-20 and of course the Commodore 64. The kit starts with installing a few discrete parts — resistors,  capacitors, and diodes.  Then come the IC sockets. [Taylor and Amy] ran into a bit of trouble when it came time to install the chips. While installing the 40-pin 65C21 Peripheral Interface Adapter (PIA), one pin bent under the socket. [Taylor] popped the chip back out, and replaced it — which resulted in 3 bent pins!

Anyone who’s installed new DIP parts has been through this. The pins are always bent out a bit from the factory. The old “Bend it in using a table” method usually works — but if you want perfect pins, try a pin straightener. These versatile tools can even be 3D printed.

Once the pin problems are solved, it’s time to power up the kit and see if it will work.  That’s when we get to see that magic moment when a project first comes to life. Check out the video – you’ll see what we mean.

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Fuel Cell Turns PET And Carbon Dioxide Into Useful Chemicals

June 21, 2023 by 16 Comments

The University of Cambridge has a novel fuel cell design that can grab CO2 from the atmosphere or industrial processes and, combined with waste PET plastic, provides syngas and glycolic acid, a product used in some cosmetics. You can read about the device in a recent paper.

The strange juxtaposition of CO2 and PET is no accident. The processes work together with solar energy. There is no external voltage required, but the cell operates as a photocell to produce electricity from the solar energy. Removing both CO2 and waste plastic from the environment is a good thing.

Syngas is hydrogen and carbon monoxide and finds use in producing methanol and ammonia. It also will work as a fuel that can replace gasoline when gasoline isn’t available. It has a few other uses, like reducing iron ore to sponge iron and even converting methanol to gasoline.

The technology has a ways to go to operate at scale, and we doubt this will ever be a consumer item since you are unlikely to need syngas or glycolic acid in your home or vehicle. But it still is a promising technique to reduce both greenhouse gas and plastic waste in one swoop.

We’ve looked at other ways to grab carbon dioxide and make it useful. If you want to make your own syngas, there are other ways to do it.

Researchers Find “Inert” Components In Batteries Lead To Cell Self-Discharge

February 6, 2023 by 11 Comments

When it comes to portable power, lithium-ion batteries are where it’s at. Unsurprisingly, there’s a lot of work being done to better understand how to maximize battery life and usable capacity.

Red electrolytic solution, which should normally be clear.

While engaged in such work, [Dr. Michael Metzger] and his colleagues at Dalhousie University opened up a number of lithium-ion cells that had been subjected to a variety of temperatures and found something surprising: the electrolytic solution within was a bright red when it was expected to be clear.

It turns out that PET — commonly used as an inert polymer in cell assembly — releases a molecule that leads to self-discharge of the cells when it breaks down, and this molecule was responsible for the color change. The molecule is called a redox shuttle, because it travels back and forth between the cathode and the anode. This is how an electrochemical cell works, but the problem is this happens all the time, even when the battery isn’t connected to anything, causing self-discharge.

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ERRF 22: Recreator 3D Turns Trash Into Filament

October 21, 2022 by 28 Comments

In Back to the Future, Doc Brown returns to 1985 with a version of his DeLorean time machine that has been modified with technology from the future. After telling Marty they need to go on yet another adventure, Doc recharges the DeLorean’s flux capacitor and time circuits by tossing pieces of garbage into the slick Mr. Fusion unit mounted to the rear of the vehicle. The joke being that, in the future, you could simply head over to the local big box store and pick up a kitchen appliance that’s capable of converting waste matter into energy.

Unfortunately, we’re nowhere near powering our homes with banana peels and beer cans. But if the Recreator 3D is any indication, the technology required to turn plastic bottles rescued from the trash into viable PET filament for your 3D printer is all but upon us. While there are still some aspects of the process that could stand to be streamlined, such as fusing multiple runs of filament together into one continuous roll, the core concepts all seem to be in place.

The MK5Kit Mini is currently in development with LDO Motors.

Creator [Josh Taylor] made the trip out to the 2022 East Coast RepRap Festival to not only show off the Recreator 3D, a project he’s been working on now for over a year, but to get people excited about the idea of turning waste plastic into filament. It’s not necessarily a new concept, and in fact [Josh] says earlier efforts such as the PETBOT are what inspired him to create his own open source take on the “pultrusion” concept.

According to [Josh], actually printing with the recycled filament isn’t that different from using commercial PETG, though it’s recommended you lower your speeds. A nozzle temperature of around 260 °C seems to work best, with the bed at 70 °C. Interestingly, the filament produced by the process is actually hollow inside, so the most critical change to make is increasing your extrusion rate to about 130% of normal to compensate for the internal void.

The current revision of the Recreator 3D, known as the MK5Kit, can be assembled using several core components salvaged from a low-cost Ender 3 printer in addition to a number of parts that the user will need to print themselves. For those who’d rather not source the parts, [Josh] says he hopes to get formal kits put together sometime next year, thanks to a partnership with LDO Motors.

But ultimately, [Josh] says the most important thing to him is that the plastic is recycled instead of getting sent to a landfill or incinerator. So whether you build a Recreator 3D or come up with your own design, all are welcome to the PET Pultruders United Facebook group he’s created to discuss the finer points of turning plastic trash into treasure.

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PETamentor2 Is Latest To Turn Bottles Into Filament

October 16, 2022 by 24 Comments

[Ondřej Šraitr] has several videos, including the one you can watch below, about his PETamentor2 — a machine for turning PET bottles into printable filament. You can grab the files on Thingiverse, and there aren’t many parts you have to buy.

The device looks good, and from the videos, it appears to work well. A blade slices the bottle into a strip that feeds what is essentially a hot end that pushes out the filament. The blade is adjustable to set the amount of plastic fed at any given time which is important because you need enough to create a solid piece of filament but not any more than that.

Surprisingly, the bill of materials doesn’t include any sort of microcontroller. There is a PWM speed control module to drive the 7 RPM motor and a temperature controller. Of course, you need a power supply, a heater block and a heater. The nozzle is, oddly enough, a standard 0.4 mm nozzle. You drill it out to 1.5 mm and die swell takes care of getting to the final 1.75 mm size.

It takes about 45 minutes to eat up what looks like a 1-liter bottle. The filament produced looks good in the video. We aren’t sure, but we think that was a roll of solder used as a ballast weight on top of the bottle keeping it moving in a downward direction. Bottles imply wetness, of course, so after producing the filament, it needs to be dried.

This is the second version of the machine and we were a bit surprised that we never saw a video of the filament in use. But it looks like it would work and it isn’t like we haven’t seen this technique used before. In fact, we’ve seen it several times. We can’t remember any that looked as stylish as the PETamentor2, though, and we are interested to hear about anyone’s results with the resulting filament.

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