Easy Frequency Counter Looks Good, Reads To 6.5 MHz

December 10, 2020 by Al Williams 12 Comments

We were struck by how attractive [mircemk’s] Arduino-based frequency counter looks. It also is a reasonably simple build. It can count up to 6.5 MHz which isn’t that much, but there’s a lot you can do even with that limitation.

The LED display is decidedly retro. Inside a very modern Arduino Nano does most of the work. There is a simple shaping circuit to improve the response to irregular-shaped input waveforms. We’d have probably used a single op-amp as a zero-crossing detector. Admittedly, that’s a bit more complex, but not much more and it should give better results.

Continue reading “Easy Frequency Counter Looks Good, Reads To 6.5 MHz” →

Mind-Controlled Beer Pong Gets Easier As You Drink

December 9, 2020 by Kristina Panos 1 Comment

Wouldn’t it be nice if beer pong could somehow get easier the more you drink? You know, so you can drink more? [Ty Palowski] has made it so with automated, mind-controlled beer pong.

[Ty] started by making a beer pong table that moves the cups back and forth at both ends. An Arduino Nano controls a stepper that controls a slider, and the cups move with the slider through the magic of magnets. The mind control part came cheaper than you might think. Back in 2009, Mattel released a game called Mind Flex that involves an EEG headset and using brain waves to guide a foam ball on a stream of air through a little obstacle course. These headsets are available for about $12 on ebay, or at least they were before this post went up.

[Ty] cracked open the headset added an HC-06 Bluetooth module to talk to the Arduino. It’s using a program called Brainwave OSC to get the raw data from the headset and break it into levels of concentration and relaxation. The Arduino program monitors the attention levels, and when a certain threshold of focus is reached, it moves the cups back and forth at a predetermined speed ranging from 1 to an impossible-looking 10. Check out the two videos after the break. The first one covers the making of the the automatic beer pong part, and the second is where [Ty] adds mind control.

We’ve seen a different headset — the hacker-friendly NeuroSky Mindwave — pop up a few times. Here’s one that’s been hacked to induce lucid dreaming.

Continue reading “Mind-Controlled Beer Pong Gets Easier As You Drink” →

Parkinson’s Spoon Uses Control Theory For Good

December 6, 2020 by Al Williams 18 Comments

When we first saw [Barqunics’] design for a self-stabilizing spoon for people suffering from Parkinson’s disease, we wondered how well something like that could work. But take a look at the video below and you’ll see this does a fine job of responding to the user’s hand movements and keeping the spoon perfectly level through a wide range of motion.

There’s at least one commercial product that attempts to stabilize a spoon in the same way so that people suffering from that affliction can retain a measure of independence. This shows that you don’t need injection molding and factory made boards to prove the concept. An MPU6050 provides sensor information and two servo motors control the spoon using PID control.

PID — short for proportional, integral, derivative — is a way to adjust something to a desired point. For example, consider trying to heat a cup of water to 95 °C. If you simply turn the heater on full blast until you get to 95 °C, the water will actually get hotter because you’ll overshoot. Using PID, the amount of heating provided will depend on how far off you are now (proportional), how far off you’ve been over the long term (integral), and how much change you’ve effected recently (derivative). The same algorithm works for spoon-balancing and many other types of controls.

This isn’t the first bootstrapped assistive spoon project we’ve seen. We even looked at the commercial version, awhile back.

Continue reading “Parkinson’s Spoon Uses Control Theory For Good” →

Slot Machine Has A Handle On Fun

December 5, 2020 by Kristina Panos 2 Comments

For some reason, when slot machines went digital, they lost their best feature — the handle. Who wants to push a button on a slot machine, anyway? Might as well just play video poker. [John Bradnam] seems to agree, and has built an open-source three-color matrix slot machine complete with handle.

In this case, you’ll be losing all of your nickels to an Arduino Pro Mini. The handle is an upgrade to an earlier slot machine project that uses three 8×8 matrices and a custom driver board. When the spring-loaded handle is pulled, it strikes a micro switch to spins the reels and then snaps back into place. Between each pull, the current score is displayed across the matrix. There’s even a piezo buzzer for victory squawks. We only wish the button under the handle were of the clickier variety, just for the feels. Check out the short demo video after the break.

If you’re not a gambler, you could always turn your slot machine into a clock.

Continue reading “Slot Machine Has A Handle On Fun” →

Fans Add Reality To Virtual Driving

December 5, 2020 by Al Williams 16 Comments

A few decades ago you might have been satisfied with a crude wireframe flight simulator or driving a race car with the WASD keys. Today, gamers expect more realism, and [600,000 milliliters] is no different. At first, he upgraded his race car driving chair and put on VR goggles. But watching the world whiz by in VR is you can’t feel the wind on your face. Armed with a 3D printer, some software, and some repurposed PC fans, he can now feel the real wind in virtual reality. You can see the build in the video, below.

The electronics are relatively straightforward and there is already software available. The key, though, is the giant 3D printed ducts that direct the airflow. These are big prints, so probably not for some printers, but printers are getting bigger every day. The fan parts are from Thingiverse, but the enclosures are custom and you can download them from the blog post.

Continue reading “Fans Add Reality To Virtual Driving” →

Flipbook Automation Saves Your Thumb

December 4, 2020 by Al Williams 3 Comments

You’ve probably seen a flipbook. That’s a book with pictures on each page. Each picture is slightly different than the last one so if you flip rapidly through the book you get a little animation. We like the German word, Daumenkino, which translates as “thumb cinema” and that seems appropriate. [Barqunics] put a decidedly new twist on this old technology. His flipbook senses a viewer and automatically flips the pages using a motor. You can see the Arduino-controlled device in the video below.

The presence detection is a ubiquitous sonar sensor. The frame is easy to make since it uses cardboard and hot glue. A DC motor like you find on many toy cars or robots provides the rotation. No 3D printing needed, but we did think it would be easy to 3D-print or laser-cut the pieces.

Continue reading “Flipbook Automation Saves Your Thumb” →

Bet You Didn’t Know Arduinos Are Psychic

November 24, 2020 by Kristina Panos 3 Comments

Are you running out of ways to entertain yourself and your family? If you’ve read all the books and watched all the movies, it might be time to explore the psychic abilities of silicon. [Hari Wiguna] has just the trick to keep them guessing for a good long time.

This trick doesn’t take much, just a couple of Arduinos, some momentary buttons, a number pad, and a large helping of math. As you can see in the demo after the break, there is nothing connecting the two, not even 802.11(n). On the randomizer Arduino, [Hari] generates random numbers with the push of a button until the audience sees one they like. Then [Hari] locks in the number with the other button.

What happens next is key: the randomizer generates another random number, but uses it as a hint to set a sentinel digit. The randomizer Arduino subtracts the larger of the two digits in the number from nine and stores the result as the flag. When the next number comes up that has the flag digit in the correct place, the number after that will be the random number chosen at the beginning.

The psychic Arduino’s secret is that it knows the first guess it receives is special. It does the same sentinel digit math as the randomizer, so when the guesser enters the guess with the sentinel digit, it knows the next number entered is the winner. Clear as mud? Check out the second video below where [Hari] explains the trick, a new take on a magic classic.

Looking for a more exciting way to generate random numbers? Try using fish tanks, lava lamps, or muons from outer space.

Continue reading “Bet You Didn’t Know Arduinos Are Psychic” →