Banana Bomb Is Likely To Get You In Trouble

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.

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KiCad Gets Banana For Scale

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.

SpotMini Struts Its Stuff

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.

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Making Music With Clojure And Bananas

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.”

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Sand Cast Banana For Scale Is So Metal

If you’ve been on Reddit over the past year, you’ve likely encountered the “banana for scale” meme. [BFG121] felt that the size variation of bananas would not do – there needed to be a standard. He decided to make a metal banana out of re-purposed aluminum. He created his own furnace out of everyday objects including a hair dryer, metal bucket, cement, fire clay, and sand. [BFG121] used a typical banana as the reference for his sand casting mold. After melting the aluminum in his homemade furnace, he poured it into the empty mold, making sure there was an extra hole for the displaced air to escape. The end result is a perfect replica of a banana. [BFG121] made two aluminum bananas, and stamped each one with a serial number. One was given to Imgur headquarters while the other was auctioned on eBay. The winning bid (#39) was $67 USD, a very good ROI.

If you want to learn more about metal casting, check out myfordboy’s channel on YouTube.  You can also see an example of the “banana for scale” in this Hackaday article about a giant spirograph. Our only suggestion to [BFG121] is to send some to ASTM, NIST, and BIPM!

[via Reddit]

Fruit Piano Uses A Different Circuit Than The Makey Makey


[Hasbi Sevinç] is using perishable goods in his electronics project. The orange, tomato, and two apples seen above act as keys for the virtual piano. The concept is the same as the Makey Makey which is often demonstrated as a banana piano. This implementation uses an Arduino to read the sensors and to connect to the computer running the piano program.

You can see there’s a fair amount of circuitry built on the breadboard. Each piece of fruit has its own channel to make it into a touch sensor. The signal produced when your finger contacts the food is amplified by transistors connected in a Darlington pair. That circuit drives the low side of a optoisolator transmitter. The receiving side of it is connected the I/O pin of the Arduino. You can see the schematic as well as a demo clip after the break.

This use of hardware frees up a lot of your microcontroller cycles. That’s because projects like this banana piano use the timers to measure RC decay. [Hasbi’s] setup provides a digital signal that at most only needs to be debounced.

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