Hackaday Podcast Episode 277: Edible Robots, A Personal Eclipse, And DIY PCBs To Die For

June 28, 2024 by Kristina Panos No comments

This week on the Podcast, it’s Kristina’s turn to ramble on alongside Editor-in-Chief Elliot Williams. First up in the news: Paul Allen’s Living Computers Museum + Labs is being liquidated at auction after just 12 years of being open to the public. In Hackaday news, the 2024 Business Card Challenge ends next Tuesday, July 2nd, so this is your weekend to shine! Also, you’ve got about two weeks to get your talk proposals in for this year’s Supercon. (Can you believe it’s only four months away?)

Then it’s on to What’s That Sound, at which Kristina made a couple of close-but-no-cigar guesses. Can you get it? Can you figure it out? Can you guess what’s making that sound? If you can, and your number comes up, you get a special Hackaday Podcast t-shirt.

Then it’s on to the hacks, beginning with a $3 smartwatch that can run Python, and a completely DIY analog tape recording solution. We’ll talk about making your wireless keyboard truly low power, all the steps you can take to produce perfect PCBs at home, and AI in a font. Finally, we talk about the dangers of a curious childhood, and talk about a dotcom hardware solution that could have gone far, given the right business model.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Download and savor at your leisure.

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A PCB business card that plays tic-tac-toe with red and blue LEDs.

2024 Business Card Challenge: Go Tic-Tac-Toe-to-Toe With Them

June 24, 2024 by Kristina Panos 4 Comments

There is perhaps no more important time to have a business card than when you’re in college, especially near the end when you’re applying for internships and such. And it’s vital that you stand out from the crowd somehow. To that end, Electrical & Computer Engineer [Ryan Chan] designed a tidy card that plays tic-tac-toe.

Instead of X and O, the players are indicated by blue and red LEDs. Rather than having a button at every position, there is one big control button that gets pressed repeatedly until your LED is in the desired position, and then you press and hold to set it and switch control to the other player. In addition to two-player mode, the recipient of your card can also play alone against the ATMega.

The brains of this operation is an ATMega328P-AU with the Arduino UNO bootloader for ease of programming. Schematic and code are available if you want to make your own, but we suggest implementing some type of changes to make it your own. Speaking of, [Ryan] has several next steps in mind, including charlieplexing the LEDs, using either USB-C or a coin cell for power, upgrading the AI, and replacing the control button with a capacitive pad or two. Be sure to check it out in action in the two videos after the break.

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A solar-powered decibel meter the size of a business card.

2024 Business Card Challenge: NoiseCard Judges The Sound Around You

June 22, 2024 by Kristina Panos 6 Comments

Let’s face it: even with the rise of the electric car, the world is a noisy place. And it seems like it has only gotten worse in recent years. But how can we easily quantify the noise around us and know whether it is considered an unhealthy decibel level?

That is where the NoiseCard comes in. This solar-powered solution can go anywhere from the regrettable open office plan to the busy street, thanks to a couple of 330 µF capacitors. It’s based on the low-power STM32G031J6 and uses a MEMS microphone to pick up sound from the back of the card, which the code is optimized for. Meanwhile, the LEDs on the front indicate the ambient noise level, ranging from a quiet 40 dB and under to an ear-splitting 105 dB or greater.

When it comes to building something the size of a business card, every component is under scrutiny for size and usefulness. So even the LEDs are optimized for brightness and low power consumption. Be sure to check it out in action after the break in various environments.

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A treadmill with a doorbell alert in one of the cup holders.

See Them Knocking With A Doorbell Alert

June 21, 2024 by Kristina Panos 8 Comments

Picture it: you’re on the treadmill, running through a forest, sweating like a pig, and the doorbell rings because a package is being delivered. Would you even hear it? Chances are, if you’re rocking out to music on headphones and your treadmill is as noisy as [Antonio]’s, you wouldn’t, and you’d once again face the dreaded ‘we’ll try later’ slip.

What you need is something that thing listens for the doorbell and flashes a giant 20 mm red LED to alert you. Could this be done with a 555? Yes, in fact, [Antonio] used a pair of them in the form of the 556 on the alert side.

The first 555 is wired up in astable mode to control the tempo of the flashing light, and the second timer is in monostable mode to control the length of time the light flashes. Power comes from the doorbell’s 9V, which is wired up through an existing Ethernet jack.

Now whenever the doorbell rings, [Antonio] has 60 seconds of flashing light in order to react, stop the treadmill, and jump off to answer the door. To conserve power when [Antonio] is relaxing, there’s an on/off switch.

Can You Freeze-Dry Strawberries Without A Machine?

June 20, 2024 by Kristina Panos 45 Comments

Summer has settled upon the northern hemisphere, which means that it’s time for sweet, sweet strawberries to be cheap and plentiful. But would you believe they taste even better in freeze-dried format? I wouldn’t have ever known until I happened to get on a health kick and was looking for new things to eat. I’m not sure I could have picked a more expensive snack, but that’s why we’re here — I wanted to start freeze-drying my own strawberries.

While I could have just dropped a couple grand and bought some kind of freeze-drying contraption, I just don’t have that kind of money. And besides, no good Hackaday article would have come out of that. So I started looking for alternative ways of getting the job done.

Dry Ice Is Nice

Dry ice, sublimating away in a metal measuring cup. — Image via Air Products

Early on in my web crawling on the topic, I came across this Valley Food Storage blog entry that seems to have just about all the information I could possibly want about the various methods of freeze-drying food. The one that caught my eye was the dry ice method, mostly because it’s only supposed to take 24 hours.

Here’s what you do, in a nutshell: wash, hull, and slice the strawberries, then put them in a resealable bag. Leave the bag open so the moisture can evaporate. Put these bags in the bottom of a large Styrofoam cooler, and lay the dry ice on top. Loosely affix the lid and wait 24 hours for the magic to happen.

I still had some questions. Does all the moisture simply evaporate? Or will there be a puddle at the bottom of the cooler that could threaten my tangy, crispy strawberries? One important question: should I break up the dry ice? My local grocer sells it in five-pound blocks, according to their site. The freeze-drying blog suggests doing a pound-for-pound match-up of fruit and dry ice, so I guess I’m freeze-drying five entire pounds of strawberries. Hopefully, this works out and I have tasty treats for a couple of weeks or months. Continue reading “Can You Freeze-Dry Strawberries Without A Machine?” →

A persistence-of-vision business card which displays information when shaken (not stirred).

2024 Business Card Challenge: Make Them Shake Your Handiwork

June 11, 2024 by Kristina Panos 2 Comments

Before COVID, people traditionally sealed their initial introduction to each other with a handshake. Nowadays, that activity seems kind of questionable. But you can still give them something to shake if you build this persistence of vision (POV) business card from [chaosneon] to show your credentials in blinkenlights form.

As you might have guessed, the input comes from a tilt switch. The user simply shakes the card back and forth, and the sensor detects the direction and cadence of the shake. Cleverly, the pattern plays forward-ways on the swing, and backwards on the back stroke, which just reinforces the POV effect. Don’t worry about how slow or fast to shake it, because the timing adjusts for your speed.

The first version used individual white LEDs, hand-soldered to an ATtiny2313. Now, in the updated version which you can see in the demo video after the break, [chaosneon] is using an RGB NeoPixel strip, which only needs one data wire to connect to the microcontroller. Thanks to this, [chaosneon] was able to to downsize to an ATtiny85.

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A business card-sized, solar-powered weather station.

2024 Business Card Challenge: Weather Or Not You Get The Job

June 11, 2024 by Kristina Panos 6 Comments

What’s the easiest way to break the ice with someone you’ve just met? If you’re not immediately talking shop, than it’s probably the time-tested subject of the weather. So what better way to get the conversation started than with a lovely solar-powered circuit sculpture of a business card that displays the weather?

We love that the frame has a built-in stand; that’s a great touch that really turns this card into something that someone might keep on their desk long-term. The brains of this operation is an ESP32 TTGO E-paper board, which checks the battery voltage first before connecting to Wi-Fi and getting data from the OpenWeatherMap API. It displays the information and then goes to sleep for 15 minutes.

For power, [BLANCHARD Jordan] is using a 5 V solar panel and a small battery from an old vape pen. We love to see projects that keep those things out of the landfills, so don’t sleep on using them.

You have just a few weeks left to enter the 2024 Business Card Challenge, so fire up those soldering irons and get hackin’!