Pulse Oximetry Sensor Judges Your Coffee Roast

October 22, 2020 by Donald Papp 24 Comments

Breakout board for the MAX30101, which [Zach] used as the basis of his roast gauge. The sensor is at the top edge of the board.

Parts designed and marketed for a specific application can nevertheless still be useful in other ways, and whenever that happens, it’s probably the start of a pretty good hack. Using a sensor for something other than its intended purpose is exactly what [Zach Halvorson] did to make the Roast Vision device, which uses the MAX30101, a sealed optical sensor intended mainly for pulse oximetry and heart-rate monitoring.

[Zach] is instead using that sensor to measure the roast level of coffee beans, and assign a consistent number from 0 to 35 to represent everything from Very Dark to Very Light. Measuring a bean’s roast level is important to any roaster seeking accuracy and consistency, but when [Zach] found that commercial roast gauges could easily cost over a thousand dollars, he was sure he could do better.

[Zach] settled on using a Sparkfun MAX30101 breakout board to develop his device, and Sparkfun shared an informative blog post that demonstrates how making hardware and tools more accessible can help innovative ideas flourish. The Roast Vision device has a 3D printed enclosure, and a simple top-loading design with an integrated sample cup makes it easy to use. One simply puts about a teaspoon of finely-ground coffee into the sample cup, and the unit provides a measurement in a couple of seconds. Fortunately the sensor works just fine though an acrylic window which means the device can be sealed; a handy feature for a tool that will spend a lot of time around ground coffee.

The joys of fresh roasted coffee is something that is perfectly accessible to those making small batches at home. There are commercial options for small roasters of course, but should you wish to go the DIY route, check out our own Elliot Williams’ guide on making a low-cost DIY roaster.

Gas Powered Blender Packs Real Grunt

October 16, 2020 by Lewin Day 17 Comments

Whether you’re into fruit smoothies or icy blended cocktails, a blender comes in handy when preparing these beverages in the kitchen. But, if a small electric motor can do the job well, a noisy combustion engine can certainly do it louder. This is demonstrated ably by this project from [JT Makes It].

The build is a steel-framed contraption, mounting a small gas engine of the type you’d typically find in a weed trimmer or other garden tool. It’s attached to a shaft allowing it to spin a blender blade at up to 41,000 rpm when unloaded. A stout metal container is mounted on top, along with a plexiglass lid to ensure the contents of the bowl don’t escape when the blender is in action.

It’s a fun build, and one that has no trouble turning a bucket of apples into mush in under 60 seconds. More realistically, [JT] is able to whip up several litres of blended cocktail without major effort, which would be great for parties. Though, we do imagine the burning oil and gas fumes does somewhat spoil the taste sensation. We’ve seen similar hacks before, like this nitro-fuelled pencil sharpener. Video after the break.

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Fermenting Yogurt With The Help Of Hardware

September 26, 2020 by Lewin Day 15 Comments

Fermentation is a natural process that has been exploited by humanity for millennia. Behind such favorites as cheese and beer, it takes just the right conditions to get the desired results. To aid in this process, and to explore the crafts of their ancestors, [Victoria] and [Petar] created an electronic fermentation quilt.

Bulgarian yogurt was the tasty end result from this work.

Anyone familiar with breadmaking will be familiar with throwing a cloth over dough when left to rest. This is all about temperature management, providing optimum conditions for the yeast to work their magic. This fermentation quilt takes things to the next level, integrating soft heater pads and temperature sensing hardware into the fabric itself. Rather than acting as a simple insulator, the quilt can actively supply heat where needed, switching off when reaching the set temperature. In this example, the quilt is set to maintain a temperature of 45 degrees for the optimum production of Bulgarian yogurt.

The fermentation quilt serves as an excellent example of what can be achieved when combining textiles with smart electronics. Tools like Adafruit’s Lilypad and conductive thread all come together to make this a functional and useful device, and shows that electronic textiles aren’t just limited to blinky wearables.

Fermentation is a popular topic among hackers, with [Trent Fehl]’s Supercon talk at the 2019 Supercon covering similar ground from a sourdough perspective. It goes to show that hardware skills can pay off in the kitchen, too!

Something’s Brewing Up In The Woods – And It Looks Stunning

August 17, 2020 by Sven Gregori 9 Comments

Caffeine fuels the hacker, and there are plenty of options to get it into your system, from guzzling energy drinks to chewing instant coffee pellets. But let’s take a nice cup of coffee as input source, which itself can be prepared in many ways using all kinds of techniques. In its simplest form, you won’t need any fancy equipment or even electricity, just heat up some water over a fire and add your ground beans to it. This comes in handy if you’re camping out in the woods or find yourself in a post-apocalyptic world, and in case you still prefer a stylish coffee maker in such a situation — why let an apocalypse ruin having nice things? — you’re in luck, because [Andreas Herz] designed this nifty looking off-the-grid coffee maker.

The design somewhat resembles a certain high-end precision coffee maker that even fictional billionaires approve of, which [Andreas] created in Fusion 360 and is available online. The device base is made from brass, wood, and silicone he cast from a 3D printed mold, while the glass and ceramic parts — i.e. the water tank and coffee pot — are simply store bought. [Andreas] opted for fuel gel as heat source, which burns under a copper coil that acts as heat exchanger and starts the actual brewing process. It took him a few attempts to get it right, and in the end, a coat of black exhaust paint did the trick to get the temperatures high enough.

This may not be the fastest coffee maker, as you will see in the video after the break, but choosing a different fuel source might fix that — [Andreas] just went the safe(r) way by using fuel gel here. But hey, why rush things when you’re camping or having a cozy time in a cabin anyway. Now all you need is the right blend, maybe even your own, made with a camp stove coffee roaster. Of course, in case of an actual apocalypse, you may not have easy access to a CNC router or 3D printer, but then there’s always the option to build an espresso machine from salvaged motorcycle parts.

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Smoking Meat With A Commodore 64

July 27, 2020 by Tom Nardi 27 Comments

When [Deadline] couldn’t find a replacement control module for his Masterbuilt electric smoker, he could have just tossed the thing in the trash. Instead, he decided to come up with his own system to take over for the smoker’s original brain. Basing it around the nearly 40 year old Commodore 64 probably wouldn’t have been our first choice, but it’s hard to argue with the end result.

Connectors to control the smoker’s hardware.

At the most basic level, controlling an electric smoker like this only requires a temperature sensor, a relay to control the heating element, and something to get those two devices talking to each other. But for the best results you’ll also want some kind of a timer, and an easy way to change the target temperature on the fly. Connecting the relay and temperature sensor up to the back of the C64 was easy enough, all he had to do was write the BASIC code to glue it all together.

This hack was made considerably easier thanks to the fact that the Masterbuilt’s original controller interfaced with the smoker by way of a couple relatively well documented connectors. So instead of having to mess with any of the mains voltage electronics, he simply had to bring a wire in the connector high to fire up the smoker’s heating element. This bodes well for anyone looking to replace the controller in a similar smoker, with a C64 or otherwise.

In the past we’ve seen some very impressive custom smoker controllers that look as though they could easily be adapted for use with these commercial units. Though the true smoke aficionados might prefer building the entire thing to their exacting specifications.

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Wobble Disk Coffee Roaster Gets The Beans Just Right

July 23, 2020 by Lewin Day 16 Comments

Coffee roasting is an art or a science, depending on who you talk to. Both camps will however agree that attention to detail is key. Many diehard beanheads, as they’re known, will go so far as to create their own roasting hardware to get the job done just right. [Larry Cotton] is one such builder, who has created an elegant roaster to get his brew just right.

The build is based around a wobble disk design. This consists of a round plate fixed at a 45-degree angle to a rotating shaft. As the shaft spins, the disk gently sweeps and agitates the roast, allowing the batch to heat up evenly without burning the beans. It’s a two-part design, with heat gun parts in the base to generate the hot air for the roasting process. The bean basket sits on top, held in place by magnets that also act as a conduit for the wobble disk motor’s power supply.

It’s a tidy build, which allows for accurate roasting and easy dumping of the beans once finished. If you’re a serious beanhead yourself with a few hacks up your sleeve, be sure to let us know! Video after the break.

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Tend Your Garden… Again

July 16, 2020 by Bryan Cockfield 55 Comments

In the early 1940s, several countries saw an incredible shift in agriculture. What were called “victory gardens” were being planted en masse by people from all walks of life, encouraged by various national governments around the world. Millions of these small home gardens sprang up to help reduce the price of produce during World War 2, allowing anyone with even the tiniest pot of soil to contribute to the war effort.

It’s estimated that in 1943 alone, victory gardens accounted for around one third of all vegetables produced in the United States. Since then, however, the vast majority of these productive gardens have been abandoned in favor of highly manicured, fertilized, irrigated turfgrass (which produces no food yet costs more to maintain), but thanks to the recent global pandemic there has been a resurgence of people who at least are curious about growing their own food again, if not already actively planting gardens. In the modern age, even though a lot of the folk knowledge has been lost since the ’40s, planting a garden of any size is easier than ever especially with the amount of technology available to help.

As someone who not only puts food on the table as a writer for a world-renowned tech website but also literally and figuratively puts food on the table as a small-scale market farmer, there are a few things that I’ve learned that I hope will help if you’re starting your first garden.

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