“I really like your floating banana.” If that’s something you’ve always wanted your guests to say when visiting your living room, this levitating banana project from [ElectroBing] is for you.
The design is simple. It relies on a electromagnet to lift the banana into the air. As bananas aren’t usually ferromagnetic, a simple bar magnet is fitted to the banana to allow it to be attracted to the electromagnet. One could insert the magnets more stealthily inside the banana, though this would come with the risk that someone may accidentally consume them, which can be deadly.
Of course, typically, the magnet would either be too weak to lift the banana, or so strong that it simply attracted the banana until it made contact. To get the non-contact levitating effect, some circuitry is required. A hall effect sensor is installed directly under the electromagnet. As the banana’s magnet gets closer to the electromagnet, the hall effect sensor’s output voltage goes down. Once it drops below a certain threshold, a control circuit cuts power to the electromagnet. As the banana falls away, power is restored, pulling the banana back up. By carefully controlling the power to the electromagnet on a continuous basis, the banana can be made to float a short distance away in mid-air.
It’s a fun build, and one that teaches many useful lessons in both physics and electronics. Other levitation techniques exist, too, such as through the use of ultrasound. Video after the break.
Continue reading “Levitating Banana Is An Excellent Conversation Starter” →
If you ask a normal person to pick a random number, they’ll usually just blurt out a number. But if you ask a math-savvy person for a random number, you’ll probably get a lecture about how hard it is to pick a truly random number. But if you ask [Valerio Nappi], you might just get a banana.
His post, which is in two parts, details how what computers generate are actually pseudo-random numbers. You can easily make sure that every number has the same probability of selection as any other number. The problem is that you have to start with something — usually called a seed. For the purposes of playing games, for example, you can grab some source of entropy like how many microseconds since a hardware timer last rolled over, the number of input pulses you’ve received from a mouse lately, or how long you had to wait for the enter key to depress after asking the user to press it. But if you know that seed and the algorithm you can perfectly predict what number the computer will generate next so it isn’t truly random.
Continue reading “Yes We Have Random Bananas” →
If there’s one thing Hollywood loves, it’s a ticking clock to create drama. Nuclear weapons, terrorist bombs, and all manner of other devices have been seen featuring foreboding numbers counting down on a series of 7-segment displays. In this vein, [deshipu] developed a rather ridiculous take on the classic trope.
The project is built around a ticking four-digit display. The blue LEDs give it a modern touch, and it’s attached on top of an Arduino Pro Mini 3.3V. This enables the whole module to be powered by a coin cell, for an incredibly compact and tidy timer that is barely bigger than the display itself. There’s also a buzzer attached, which chirps each second, somewhat heightening the stress level in the immediate vicinity.
With a functioning timer, [deshipu] then went for comedy points, by hooking it up to a trio of bananas. This is widely considered more courteous than attaching it to a detonator circuit and actual dynamite, and is key to staying off government watchlists.
It’s a piece that would be amusing at a Halloween party or similar, and is easily completed by any beginner learning Arduino. It goes without saying that, while this is amusing, it’s a build that should very much not be bandied about in public or used for a prank. In this day and age, even touting a custom clock can draw unwelcome attention, so it’s important to be careful. Video after the break.
Continue reading “Banana Bomb Is Likely To Get You In Trouble” →
Over the years we’ve seen KiCad grow from a niche, somewhat incomplete, but Open Source PCB design suite to a full-featured extravaganza of schematics and board layouts. We’ve plumbed the depths of keys and kais and queues and quays, and KiCad just had its first conference last weekend. While we wait for the rest of the talks to be published, there’s a special treat for KiCad users everywhere. Here’s a banana for scale.
Have you ever worried your PCB was too big? Confused if you’re working in inches or millimeters? Do you just want to know the scale of your PCB? Just add this footprint to your KiCad project, and you’ll have a banana on your board view. This is immediate visual feedback, giving you all the information you need to continue on with your design. There’s a 2D view and a 3D view. It’s something no electrical engineer should be without. All of this can be yours for the low, low, cost of free because KiCad is Open Source.
If you’re wondering what official features are in the works for the EDA suite, the first two talks from the con delve into that. project leader Wayne Stambaugh’s talk covers features new to version 5.1 and plans for 6.0. There was also a developers panel that provides insight on what goes into a large project like this one.
This is a tale as old as time. Not love, it is about keeping something you made safe from those who would destroy something beautiful. In this case, the thing of beauty is a talking banana who reads Twitch and Youtube comments. The ne’er-do-wells are trolls seeking to ban-anana the account by forcing it to recite restricted words.
The problems stem from a visit from [Greekgodx], whose followers tend toward the dark side. When they set their sights on [Mike Nichols]’ yellow automaton, things slipped into a bleak place, and a twenty-four-hour ban falls on the fruit. A bunch of filtering is done, but it isn’t enough to stop the trolls, and the tally-man adds a second permanent strike against the account. An arms race of slurs and filtering ensued until the robot was able to reject all attempts at racism.
The banana has since been peeled from the feeds, but if silly robots are your cup of tea, check out [Simone Giertz] turning a car into a computer mouse.
Continue reading “Bananas Against Racism” →
Boston Dynamics, the lauded robotics company famed for its ‘Big Dog’ robot and other machines which push mechanical dexterity to impressive limits have produced a smaller version of their ‘Spot’ robot dubbed ‘SpotMini’.
A lightweight at 55-65 lbs, this quiet, all-electric robot lasts 90 minutes on a full charge and boasts partial autonomy — notably in navigation thanks to proprioception sensors in the limbs. SpotMini’s most striking features are its sleek new profile and manipulator arm, showing off this huge upgrade by loading a glass into a dishwasher and taking out some recycling.
Robots are prone to failure, however, so it’s good to know that our future overlords are just as susceptible to slipping on banana peels as we humans are.
Continue reading “SpotMini Struts Its Stuff” →
At this point, the banana piano is a pretty classic hack. The banana becomes a cheap, colorful touch sensor, which looks sort of like a piano key. The Arduino sets the pin as a low-level output, then sets the pin as an input with a pull up resistor. The time it takes for the pin to flip from a 0 to a 1 determines if the sensor is touched.
[Stian] took a new approach to the banana piano by hooking it up to Clojure and Overtone. Clojure is a dialect of Lisp which runs in the Java Virtual Machine. Overtone is a Clojure library that provides tons of utilities for music making.
Overtone acts as a client to the Supercollider synthesis server. Supercollider has been around since 1996, and provides a wide array of sound synthesis functions. Overtone simply tells Supercollider what to do, letting you easily program sounds in Clojure.
The banana piano acts as an input to a Clojure program. This program maps the banana to a musical note, then triggers a note on Overtone’s built-in piano sampler. The result is a nice piano sound played with fruit. Of course, since Overtone and Supercollider are very flexible, this could be used for something much more complex.
After the break, a video of the banana piano playing some “Swedish Jazz.”
Continue reading “Making Music With Clojure And Bananas” →