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

[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.

The inside of a 3d printed cat treat dispenser, showing the different compartments, shaft and wires running out the back.

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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Fuel Cell Catalyst: Less Is More

A fuel cell is almost like a battery that has replenishable fuel. Instead of charging a battery with an electric current, you recharge a fuel cell with something like hydrogen or you simply consume it from a tank much as an internal combustion engine consumes gasoline. However, fuel cells usually use a catalyst — it isn’t consumed in the reaction, but it is necessary and many fuel cells use platinum as a catalyst which is expensive. But what if you could use less catalyst and get a better result? That’s what researchers in Canada and the US are claiming in a recent paper. The key isn’t how much catalyst they are using, but rather the shape of the catalyst.

Of course, everyone wants to use less of the expensive catalyst but polymer electrolyte fuel cells have had a particular problem where reducing the amount of catalyst used causes a disproportionate drop in cell performance. This new approach uses spherical catalyst support that improves the distribution and utilization of the catalyst.

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Home-Built CPU Runs With Home-Built Toolchain

A few years ago [Takaya Saeki] and fellow students of the University of Tokyo, were given a very limited instruction during their ‘CPU exercise’ class, along the lines of:

Take this ray-tracing program written in OCaml and run it on your CPU implemented on an FPGA

Splitting into groups to cover the CPU, FPU, simulator tool, and compiler toolchain, the students started with designing a RISC ISA, then designed a CPU around that. You can follow along with the retrospective writeup of the class, then dive into the GitHub pages for each of the components of the system, although the commentary is mainly in Japanese. Hey, you can google translate right? Continue reading “Home-Built CPU Runs With Home-Built Toolchain”

New Metric Prefixes Get Bigger And Smaller

It always fascinates us that every single thing that is made had to be designed by someone. Even something as simple as a bag and box that holds cereal. Someone had to work out the dimensions, the materials, the printing on it, and assign it a UPC code. Those people aren’t always engineers, but someone has to think it out no matter how mundane it is before it can be made. But what about the terms we use to express things? Someone has to work those out, too. In the case of metric prefixes like kilo, mega, and pico, it is apparently the General Conference on Weights and Measures that recently had its 27th session. As a result of that, we have four more metric prefixes to learn: ronna, quetta, ronto, and quecto.

Apparently, the new prefixes are to accommodate “big data” which is rapidly producing more data than there are atoms in the Universe. There were actually proposed earlier in a slightly different form but accepted at the conference. Apparently quecca is too close to a Portuguese swear word. So what do these actually mean? A QB (quettabyte) would be 1030 bytes while an RB (ronnabyte) is only 1027.  So 1 QB would be 1,000,000 yottabytes (YB) the previous top of the scale.

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A breadboard with a few DIP chips

Minimalist 6502 System Uses A CPU And Not Much Else

A central processing unit, or CPU, is the heart of any computer system. But it’s definitely not the only part: you also need RAM, ROM and at least some peripherals to turn it into a complete system that can actually do something useful. Modern microcontrollers typically have some or all of these functions integrated into a single chip, but classic CPUs don’t: they were meant to be placed on motherboards along with dozens of other chips. That’s why [c0pperdragon]’s latest project, the SingleBreadboardComputer, is such an amazing design: assisting its 6502 CPU are just four companion chips.

The entire system takes up just one strip of solderless breadboard. Next to the CPU we find 32 KB of SRAM, 32 KB of flash and a clock oscillator. The fifth chip is a 74HC00 quad two-input NAND gate, which is used as a very tiny piece of glue logic to connect everything together. Two of its NAND gates are used for address decoding logic, allowing either the ROM or RAM chip to be selected depending on the state of the CPU’s A15 line as well as blocking the RAM during the low phase of the system clock. The latter function is needed because the address lines are not guaranteed to be stable during the low phase and could cause writes to random memory locations.

The remaining two NAND gates are connected as an RS-flipflop in order to implement a serial output. This is needed because the CPU cannot keep its outputs in the same state for multiple clock cycles, which is required for a serial port. Instead, [c0pperdragon] uses the MLB pin, normally used to implement multiprocessor systems, to generate two-clock pulses, and stores the state in the flipflop for as long as needed. A few well-timed software routines can then be used to transmit and receive serial data without any further hardware.

Currently, the only software for this system is a simple demonstration that sends back data received on its serial port, but if you fancy a challenge you could write programs to do pretty much anything. You could probably find some inspiration in other minimalist 6502 boards, or projects that emulate a complete motherboard in an FPGA.

A Hacker Walks Into A Trade Show: Electronica 2022

Last week, the world’s largest electronics trade fair took place in Munich, so I had to attend. Electronica is so big that it happens only once every two years and fills up 14 airplane hangars. As the fairly generic name suggests, it covers anything and everything having to do with electronics. From the producers of your favorite MLCC capacitors to the firms that deliver them to your doorstep, from suppliers of ASIC test equipment to the little shop that’ll custom wind toroids for you, that’s a pretty wide scope. Walking around, I saw tomorrow’s technology today from the big players, but I also picked up some ideas that would be useful for the home gamer.

When I first walked in, for instance, I ran into the Elantas booth. They’re a company that makes flexible insulation and specialty industrial coatings. But what caught my eye was a thermoformed plastic sheet with circuit traces on it. To manufacture them, they cut out copper foil, glue it to a flat plastic sheet with a glue that has a little give, and then put it all together into a vacuum former. The result is a 3D circuit and organically formed substrate in one shot. Very cool, and none of the tech for doing that is outside of the reach of the determined hacker.

The Cool Stuff

All of the stands, big or small, try to lure you in with some gimmick. The big fish, firms with deep pockets, put up huge signs and open bars, and are staffed by no shortage of salespeople in suits. The little fish, on the other hand, have to resort to showing you the cool stuff that they do, and it’s more often the application engineers sitting there, ready to talk tech. You can guess which I found more interesting.

For instance when I walked up to an obviously DIY popcorn popper that was also showing 5000 FPS footage of kernels in mid-pop, I had to ask. The company in question was a small UK outfit that made custom programmable power supplies and digital acquisition gear that interfaced with it. You could plug in their box to some temperature probes, fire off the high-speed video camera, and control the heating and cooling profile without writing any code. Very sweet. Continue reading “A Hacker Walks Into A Trade Show: Electronica 2022”

Start Your Engines: The FPV Contest Begins Now!

There are places that you can go in person, but for everything else, there’s FPV. Whether you’re flying race quads, diving the depths in a yellow submarine, or simply roving the surface of the land, we want to see your builds. If it’s remote controlled, and you feel like you’re in the pilot’s seat, it’s FPV.

That’s you in the car.

When you say “first person view” many of you will instinctively follow up with “flight” or “drone”. But given the ease of adding a camera and remote control to almost any vehicle, there’s no reason to only fly the FPV skies. (Of course, we want to see your crazy quadcopter builds too.)

We went looking for a few less-traditional examples to whet your appetite, and we found a lot. There are super-cute FPV bots for indoors and more robust tanks for cruising around the neighborhood. In the summer, you’ll probably need an FPV lawnmower, and for the winter, naturally, an FPV snowblower or a budget-friendly FPV snow-boat. Or skip the outdoors entirely and terrorize the pool with an FPV sub.

This contest isn’t exclusively about the vehicles either. If you’re working on the tech that makes FPV possible, we want you to enter. For instance, this simple quad/drone tracker will help keep your video feed running and your mind on flying. This cockpit will make the immersion more complete. And nobody likes the jello-cam effect that excess vibration can cause, so we’d like to see camera hacks as well.

And of course, your quads. Is your FPV quad too fast, too light, or does it fly too far? Show us. The contest starts now and runs until Jan 3, 2023, and there are three $150 shopping sprees courtesy of Digi-Key on the line. Get hacking!