Build Your Own High-Temp Oven Thermometer

December 29, 2021 by 9 Comments

Looking to keep an eye on the temperature inside his wood-fired pizza oven, [Giovanni Bernardo] decided to skip the commercial offerings and build his own high-temperature thermometer using a type-K thermocouple. The end result is a no-nonsense handheld unit with a surprisingly low part count that, at least in theory, can read temperatures as high as 1023.75°C. Though we hope he’ll be pulling the pizza out long before that.

Inside the 3D printed case we find just a handful of components. The 0.91″ OLED display mounted in the front panel is wired to a Digispark ATtiny85 development board, which in turn is connected to a MAX6675 breakout board. This takes the input from the thermocouple probe and converts it into a digital signal that can be read over SPI with an Arduino library from Adafruit. Rather than going through the added complication of adding a rechargeable pack, [Giovanni] is running this thermometer from a standard 9 V battery thanks to the 5 V regulator built into the Digispark.

We especially appreciate the attention to detail [Giovanni] put into his case design. Each component is nestled into a perfectly formed pocket in the bottom of the box, and he’s even gone through the trouble of using heat-set inserts for the front panel screw holes. It would have been quicker and easier to just model up a basic box and hot glue his components in place, but he took the long way around and we respect that.

This project is another example of an interesting principle we’ve observed over the years. Put simply, if somebody is going through this much trouble to check an object’s temperature, there’s a higher than average chance they intend on eating it at some point.

a home depot surfboard

Foam Surfboard From Scratch

December 29, 2021 by 5 Comments

Have you ever wanted to make your own surfboard, but felt held back by a lack of tools, materials, or the cost of it? Drawing almost entirely from what can be found at a well-known home improvement retailer, [AndrewW1997] details the steps needed to craft your board.

In his guide, he details the difference between XPS (expanded polystyrene) and EPS (extruded polystyrene) and how each product’s closed cell and open cell nature affects the final board. Starting with two pink sheets of XPS, he laminated them together with glue to form his blank. A stringer is a long piece of wood in the middle of the surfboard that provides additional flex and strength. Some flooring plywood curved with a jigsaw provides the shape needed. Unfortunately, the blank needs to be split in half to install the stringer. However, he has a trick for gluing the blank back together without it buckling, and that trick is ratchet straps.

He cuts the foam into roughly the right shape with a hot wire. Clean up is done with sanding blocks, a plane, and a level. The next step is laminating the board with epoxy and fiberglass. Next, [Andrew] details a few considerations around the process and gets to glassing. Sanding up to 2000 grit and some polishing compound make the board gorgeous. After a bit of final curing time, you’re ready to ride some waves.

There’s a handy playlist on YouTube detailing the process so you can follow along. Once you’ve finished your surfboard, perhaps your next project will be to power it up with a jet drive. Video after the break.

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Astronaut Food Is Light Years Beyond Tang And Freeze-Dried Ice Cream

December 29, 2021 by 9 Comments

When it comes down to it, we humans have two major concerns when venturing away from home for an extended period of time: what we’ll eat, and where we will sleep. Depending on the mode of travel, you might take some snacks along, or else rely on restaurants and/or the pantry of your possible hosts. Until the day we can reliably grow many types of food in space, or that Milliways, that five-star eatery at the end of the universe is operational, astronauts and other space-bound travelers will have to bring most of their food with them.

Cubes and Tubes

Space food has its roots in military rations, which in the United States were devised during the Revolutionary War. Both the variety and delivery methods of food have changed significantly since the beginning of the space program. While the menu may have at first been limited to tubes of nutrient-rich goo, bite-sized cubes and freeze-dried powdered beverages, the fare is more far-out these days. Astronauts on the ISS even enjoy tortillas, fresh fruits, and vegetables thanks to resupply missions, though they have to eat some of these types of foods quickly.

The average astronaut has also changed quite a bit, too. At first, they were all young and super-fit ex-military men, but nowadays they are more likely to be middle-aged science-y types and women. All three of these groups have different nutritional needs when faced with the rigors of living and working in space.

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Modern Toilet Generates Energy

December 29, 2021 by 44 Comments

Environmental Engineering [Prof Jaeweon Cho] at South Korea’s Ulsan National Institute of Science and Technology specializes in water and waste management. He has developed an energy-generating toilet called BeeVi (pronounced beevee) that recycles your waste in three ways. Liquid waste is processed in a microbial reaction tank to make a liquid fertilizer. Solid waste is pumped into an anaerobic digestion tank, which results in methane gas used to power a silicone oxide fuel cell to make electricity. The remaining solids are composted to make fertilizer. The daily waste from one person is about 500 g, which can generate about 50 L of methane.

The BeeVi toilets, located on the UNIST campus, pay students in a digital currently called Ggools, or Honey Money in English. Each deposit earns 10 Ggools, which can be used to purchase coffee, instant noodles, and other items (one Ggool is equivalent to about $3.00 value). The output from this pilot project is used to partially power the building on campus, and to fertilize gardens on the grounds. If you want to learn more, here is a video lecture by [Prof Cho] (in English).

Waste management is an area of research around the world. The Gates Foundation has been funding research into this field for ten years, and has held a number of expos over the years highlighting innovative solutions, most recently being the 2018 Reinvent the Toilet Expo in Beijing. We wrote a piece about the future of toilets last year as well.

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The Current State Of Play In Autonomous Cars

December 29, 2021 by 54 Comments

Bluster around the advent of self-driving cars has become a constant in the automotive world in recent years. Much is promised by all comers, but real-world results – and customer-ready technologies – remain scarce on the street.

Today, we’ll dive in and take a look at the current state of play. What makes a self-driving car, how close are the main players, and what can we expect to come around the corner?

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Rat playing DOOM

Rats Learn To Play DOOM In This Automated VR Arena

December 29, 2021 by 29 Comments

When we run an article with “DOOM” in the title, it’s typically another example of getting the venerable game running on some minimalist platform. This DOOM-based VR rig for rats, though, is less about hacking DOOM, and more about hacking the rats.

What started as a side project for [Viktor Tóth] has evolved into quite a complex apparatus. At the center of the rig is an omnidirectional treadmill comprised of a polystyrene ball about the size of a bowling ball. The ball is free to rotate, with sensors detecting rotation in two axes — it’s basically a big electromechanical mouse upside down. The rat rides at the top of the ball, wearing a harness to keep it from slipping off. A large curved monitor sits right in front of the rat to display the virtual environment, which is a custom DOOM map.

With the VR rig built, [Viktor] worked on automating the training. A treat dispenser provides the proper motivation, while powered drive wheels engage with the ball to nudge the rat if it gets stuck in the virtual world. [Viktor] says he has trained three rats — [Romero], [Carmack], and [Tom] — to walk down a straight hallway using this automated method. As for the meat of the game — shooting monsters — [Viktor] has that covered too, with a sensor that detects when a rat rears up on its hind legs to register a shot.

Total training time to get the rats to the point seen in the video was about six weeks, and [Viktor] reports the whole thing cost him about $2000. That’s a lot of time and money, but the results are pretty interesting. If you’re more interested in minimalist DOOM builds, we understand — check out DOOM on a lightbulb, or a thermostat, or even a GPS.

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The Three Cent Motor Controller

December 29, 2021 by 20 Comments

If you follow the world of small microcontrollers you will certainly be familiar with the usual fare of Atmel, ARM Cortex, PIC, and others. But these aren’t the smallest or cheapest devices, below them is an entire category of grain-of-dust microcontrollers with minimal capabilities and at rock bottom prices. Maybe the most well known are the Padauk series of chips, whose PIC12-like architecture can be had for literal pennies. These are the famous 3 cent microcontrollers, but despite their fame they have a bit of a reputation in our community for being difficult to work with. [Ben Lim] dispels some of those ideas, by Padauk-enabling a motor and encoder from a printer to make a three cent motor controller.

The Padauk doesn’t have on-chip peripherals such as SPI, instead its IDE provides bit-banging code to do the job. This and some PID motor controller code makes for a straightforward task on the little chip, and with the help of a probably considerably more expensive MAX14870 it can drive the motor. For the curious, the code can be found in a Git Hub repository. There may be more accomplished motor controllers to be found, but we doubt you’ll find one with a cheaper microcontroller.

Want to know what the fuss is about with the Padauk? Our colleague [Maya Posch] has you covered.