Engineering Overkill Motorizes The Daily Grind

January 9, 2020 by Kristina Panos 26 Comments

You don’t tug on Superman’s cape, and you don’t come between an engineer and his coffee. And really, if all your office has for coffee is a big old BUNN that makes caffeinated trash, you don’t discourage your coworkers from the pursuit of a better brew.

[George] is over at his desk each day treating coffee like the science experiment it is: with a kettle, a Chemex, and a manual coffee grinder. Trouble is, the setup is attracting more and more attention, and [George]’s unpaid side gig as the office barista is starting to wear out his arm. He considered buying an electric grinder just long enough to laugh at the idea, and then went out to the workshop and built this beautifully over-engineered motorized mount for his manual grinder.

The only trouble with motorizing these hand grinders or even driving them with a drill is that many of them have a pentagonal shaft. But that problem was no match for [George] and his file. He soon had his linkage between the 100RPM motor and the grinder shaft and set about building the overly adequate frame.

The whole thing is gorgeous, but we particularly like the gas spring that holds the motor up out of the way while he pours in the beans. [George] probably ought to start a bean fund, if he hasn’t already. That kind of noise followed by the smell of coffee is bound to bring a few more fresh-ground converts into the fold. Grab a fresh cup and grind past the break to see this baby pulverize some beanage.

Not everyone goes for pour over coffee, but there are hacks to be done at all points on the coffee spectrum. Check out [Maya Posch]’s adventures in totally tweaking an espresso machine.

Continue reading “Engineering Overkill Motorizes The Daily Grind” →

Engineering Your Way To Better Sourdough (and Other Fermented Goods)

January 8, 2020 by Kristina Panos 23 Comments

Trent Fehl is an engineer who has worked for such illustrious outfits as SpaceX and Waymo. When he got into baking, he brought those engineering skills home to solve a classic problem in the kitchen: keeping a sourdough starter within the ideal, somewhat oppressive range of acceptable temperatures needed for successful fermentation.

A sourdough starter is a wad of wild yeasts that you make yourself using flour, water, and patience. It’s good for a lot more than just sourdough bread — you can scoop some out of the jar and use it to make pancakes, waffles, pretzels, and a host of other bread-y delights. A starter is a living thing, a container full of fermentation that eats flour and has specific temperature needs. Opinions differ a bit, but the acceptable temperature range for active growth is about 60 F to 82 F. Too cold, and the starter will go dormant, though it can be revived with a little love. But if the starter gets too hot, all the yeasts and bacteria will die.

While there are of course commercial products out there that attempt to solve this problem of temperature control, most of them seem to be aimed at people who live in some wonderland that never gets warmer than 80F. Most of these devices can’t cool, they only provide heat. But what if you live in a place with seasons where the climate ranges from hot and humid to cold and dry?

The answer lies within Chamber, a temperature-regulated haven Trent created that lets these wild yeasts grow and thrive. It uses a Peltier unit to heat and cool the box as needed to keep the mixture fermenting at 26°C /78.8°F.

Thanks to the Peltier unit, Trent can change the temperature inside the chamber simply by alternating the direction of current flow through the Peltier. He’s doing this with an H-bridge module driven by a Raspberry Pi Zero. When it starts to get too warm in the chamber, the fan on the outside wall vents the heat away. A second fan inside the chamber pulls warm air in when it gets too cold.

Trent says that Chamber performs really well, and he’s recorded temperatures as low as 60F and as high as 82F. He mostly uses it for sourdough, but it could work for other temperature-sensitive food sciences like pickling, growing mushrooms, or making yogurt. We think it could be ideal for fermenting kombucha, too.

Chamber works well enough that Trent has put further development on the back burner while he makes use of it. He does have several ideas for improvements, so if you want to help, check out his website and Github repo.

Continue reading “Engineering Your Way To Better Sourdough (and Other Fermented Goods)” →

Embedding A Smart Switch In A Java Factory

January 6, 2020 by Kristina Panos 3 Comments

When you need coffee, you don’t need any hassles standing between you and caffeination. Especially ironic hassles, like having to do more to turn on appliances inside of home automation schemes than you did without them.

[Maurice Makaay] bought a smart plug to add this beautiful drip coffee machine to his Z-Wave setup, but it isn’t all that smart. Starting the brew remotely means making sure that both the machine’s power switch and the smart plug switch are on. Some members of the household still like making their coffee the old-fashioned way, so [Maurice] came up with a smart, single switch solution to satisfy both cases.

The answer comes in the form of a Z-Wave switch that takes dual inputs and is small enough to fit inside the machine. After a lot of searching around for compatible, splash-proof parts, [Maurice] replaced the existing on/off rocker with a momentary rocker for making coffee manually. That switch labeled ‘extra heet’ used to turn the warming burner on and off. Since he never uses the burner, the switch receptacle now houses a power indicator light.

[Maurice] went about this mains appliance hack the right way — he used extra thick wires connected with lever nuts, and kept the machine’s equally beautiful spare parts and safety documentation by his side the whole time. A person could probably become a lot more comfortable with the idea of installing these by looking over [Maurice]’s pictures of the process.

You know how coffee makes everything better? Turns out ‘everything’ includes printer filament.

AirBass Lets You Jam Wherever

January 5, 2020 by Kristina Panos 11 Comments

If you play an instrument, you know how rewarding it is to watch and hear yourself reproduce your favorite songs and make new melodies. But you also know how steep the learning curve can be, how difficult it is to learn positions and notes while your body adjusts to the physical side. For stringed instruments, that means gaining muscle memory, growing fingertip calluses, and getting used to awkward arm positions.

For their final project in [Bruce Land]’s class on designing with microcontrollers, [Caitlin, Jackson, and Peter] decided to make a more accessible bass guitar. For starters, it can be placed flat on a table similar to a pedal steel guitar to get around those awkward arm positions. Instead of plucking or slapping the strings, the player wears a glove with a flex resistor on each finger, and plays the string by curling and uncurling their finger.

We think the team’s implementation of the left hand duties and fretboard is pretty clever. Each of the four strings has a break-beam detection circuit, and a single distance sensor decides where the finger is along the fretboard. Another great thing about this backpack-sized bass is that it never needs tuning. If you stay tuned, you can hear [Peter] play “Smoke On the Water” after the break.

There’s more than one way to make an air guitar — this one that does it with LIDAR.

Continue reading “AirBass Lets You Jam Wherever” →

Space-Saving Servo Tester Console Looks Space-Worthy

January 5, 2020 by Kristina Panos 7 Comments

You know how it goes — sometimes you just have to stop in the middle of a project and build yourself a tool that vastly improves your workflow as soon as it’s completed. [Ikkalebob] aka [Will Cogley] on YouTube is working on some super secret project that requires a whole bunch of servos. And since all of them have to be tested and set, he built this adorable servo tester as a time-saving gift to himself.

This tester revolves around an Adafruit 16-channel servo driver and an Arduino Uno. The servos show up on the screen in groups of four, and can be tested four at a time with the pots. The buttons let [Ikkalebob] move up and down between the groups. The SainSmart LCD proved to be more difficult to set up than others, but [Ikkalebob] did you a solid and tweaked the library. It’s available along with his code and STLs.

Speaking of STLs, we really dig the mini NASA console look and the folding enclosure. Leveraging the print process to build hinges and other things is awesome, and so is getting away with using fewer fasteners. You can see a bit of how [Ikkalebob] designed it in the video after the break.

Depending on what you’re doing with servos, you might want a different kind of testing suite. Here’s one that’s geared toward RC pilots.

Continue reading “Space-Saving Servo Tester Console Looks Space-Worthy” →

Baby’s First Jukebox Is Fun For Parents, Too

January 4, 2020 by Kristina Panos 12 Comments

Believe it or not, there’s a $400 toy mp3 player out there for kids. It looks pretty nice, with colorful buttons and a wood console and all, but those features don’t really justify the price tag. [DerThes] wanted one for his 2-year-old anyway, so he made his own ruggedized version for a whole lot less.

The simple and kid-friendly interface lets [DerThes Jr.] choose from one of nine albums to play by pushing one of the candy-colored buttons. The bottom row of buttons handle play/pause and moving through the track list. When mom and dad get tired of listening to whatever the kids are into these days, they can enter the special god mode code to access 99 of their favorite albums.

This baby boombox is built with an Arduino Uno and an Adafruit music maker shield. [DerThes] etched his own PCB to hold the buttons and the pair of shift registers needed to interface them with the Uno. If you’ve never etched before, here’s a good chance to dip your toe in the ferric chloride, because [DerThes] has the transparency in his repo and a line on a nice instructional video.

If you don’t think your toddler is ready to respect a field of momentaries, you could make a jukebox with NFC blocks.

[via Arduino blog]

DIY Trommel Sifts Compost In Style

January 2, 2020 by Kristina Panos 22 Comments

Composting is a great idea that helps you and the planet at the same time. But all that stuff is going to break down at different rates, and depending on what you put in there and how soon you want to use the compost, you’ll probably have to sift out some unwanted stuff first.

[Minnear Knives] had a bunch of apricot stones in his compost pile, and it was the pits. He did some research and decided to build his own rotary trommel to tumble out the trash. As you will see in the video after the break, it works really well. All he has to do is turn on the motor and shovel raw compost or dirt into one end. Bad stuff tumbles out the other end into a wheelbarrow, while the good stuff is sifted down into a pile under the cylinder. Just look at that rich, fluffy compost.

The best part is that he was able to make it mostly from stuff he had lying around, though he did trade some beer for the v-belt pulley. The cylinder is essentially made from mesh that’s zip-tied to bicycle rims. A 1/4 horsepower motor mounted up top uses that v-belt pulley to spin the cylinder’s rims against casters that are mounted to the frame. Thanks to the pair of bike wheels on the back, he can cart it around the ranch unassisted.

Composting doesn’t have to be any more difficult than a pile in the backyard. But if you don’t have a backyard, why not build a rotating bin that you can monitor from your phone?

Continue reading “DIY Trommel Sifts Compost In Style” →