Halloween Pumpkin Scares With An Evil Eye

November 15, 2020 by 1 Comment

These days, a classic Jack O’ Lantern just doesn’t cut the mustard. Kids are expecting to be scared by high-quality animatronics at a minimum. This haunting work by [Zero To Infinity] might just do the trick.

A real pumpkin is pressed into service in this build, with the usual threatening grin and candlelit interior. However, where it differs is in its single, animated eye. The eye itself is constructed of a pingpong ball, drawn upon with markers for a creepy bloodshot look. A pair of servos allow the eye to twitch and roll, under the command of an Arduino Nano. For further interactivity, an ultrasonic sensor is used to only trigger the pumpkin when it senses a person approaching.

It’s a fun holiday build that also serves as a great primer on how to work with servos and microcontrollers. We can imagine a more advanced setup using more sensors and pumpkins to train multiple eyes on the unsuspecting visitor. If that’s not scary enough, perhaps just make your pumpkins breathe fire instead. Video after the break.

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Cutting Balsa Wood With Air (Oh, And A Laser)

November 15, 2020 by 34 Comments

[DIY3DTech] likes using his Ortur laser cutter for balsa wood and decided to add an air assist system to it. Some people told him it wasn’t worth the trouble, so in the video below, he compares the results of cutting both with and without the air assist.

The air assist helped clear the cut parts and reduced charring in the wood. The air system clears residue and fumes that can reduce the effectiveness of the laser. It can also reduce the risk of the workpiece catching on fire.

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Interactive Subway Map Talks You Through The Route

November 15, 2020 by 2 Comments

Old-school rail monitoring systems had amazing displays of stations and tracks covered in flashing lights that tracked the progress of trains along a route. While it’s unlikely you’ll fit such big iron from the mid-20th century in your home, you can get a similar aesthetic with [Kothe’s] interactive subway information display.

The display relies on an Arduino Mega 2560 Pro Mini as the brains of the operation. It drives strings of WS2812B LEDs which correspond to stations along the various metro lines in the area. Additionally, the microcontroller drives a 4.3″ Nextion LCD display. The Nextion displays have the benefit of acting as a self-contained human machine interface, running their own controller on board. This means the Arduino doesn’t have to spend cycles driving the display, and the Nextion hardware comes with a useful software package for quickly and easily designing GUI interfaces. For further feedback, a DFPlayer MP3 module is used to allow the system to playback prerecorded voice samples that provide information on the rail system. The attractive front panel is made with lasercut acrylic and a color printed acetate sheet.

It’s a build that bears striking similarity to real rail information systems fielded by railways around the world. We can imagine such a device being particularly useful in a backpacker’s hostel or university dorm to help those new to town find their way around. If you prefer a more stripped-back aesthetic, we’ve seen a barebones PCB build done as well. Video after the break.

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An EV Conversion Engineered As A Drop-in Replacement

November 15, 2020 by 87 Comments

With electric vehicles such as the Tesla or the Leaf being all the rage and joined by fresh competitors seemingly every week, it seems the world is going crazy for the electric motor over their internal combustion engines. There’s another sector to electric traction that rarely hits the headlines though, that of converting existing IC cars to EVs by retrofitting a motor. The engineering involved can be considerable and differs for every car, so we’re interested to see an offering for the classic Mini from the British company Swindon Powertrain that may be the first of many affordable pre-engineered conversion kits for popular models.

Swindon Powertrain's demo Mini
Swindon Powertrain’s demo Mini

The kit takes their HPD crate EV motor that we covered earlier in the year, and mates it with a Mini front subframe. Brackets and CV joints engineered for the kit to drop straight into the Mini. The differential appears to be offset to the right rather than the central position of the original so we’re curious about the claim of using the Mini’s own driveshafts, but that’s hardly an issue that should tax anyone prepared to take on such a task. They can also supply all the rest of the parts for a turnkey conversion, making for what will probably be one of the most fun-to-drive EVs possible.

The classic Mini is now a sought-after machine long past its days of being dirt-cheap old-wreck motoring for the masses, so the price of the kit should be viewed in the light of a good example now costing more than some new cars. We expect this kit to have most appeal in the professional and semi-professional market rather than the budget end of home conversions, but it’s still noteworthy because it is a likely sign of what is to come. We look forward to pre-engineered subframes becoming a staple of EV conversions at all levels. The same has happened with other popular engine upgrades, and no doubt some conversions featuring them will make their way to the pages of Hackaday.

We like the idea of conversions forming part of the path to EV adoption, as we’ve remarked before.

Automatic Scoring For Skeeball Mini-Golf

November 14, 2020 by 1 Comment

Minigolf is a fun, simple pastime that has the benefit of taking up much less space than the classical game it is inspired by. [gcall1979] had built himself a small game for the lounge room, but found keeping score to be a tedious exercise. Of course, that was nothing that couldn’t be solved with some electronics!

The game consists of a skeeball-type minigolf course, where the score is determined by the hole the player puts the ball through. To track this, each hole is fitted with an IR break-beam sensor that triggers when a ball passes through. Vinyl siding is used to guide the balls going through the holes to ensure the sensor is triggered consistently. The sensors are read by an Arduino Mega, which is also responsible for flashing LEDs and updating the score throughout the game on the included 7-segment displays.

It’s a basic hack, but one that makes the game far more of a self-contained experience. No more fumbling with pencils and paper means it’s easier to focus on dominating the competition on the (miniature) green. Of course, those with dreams of the driving range might consider this recreation of the famous Floating 14th Hole!

Micropython On Microcontrollers

November 14, 2020 by 54 Comments

There are plenty of small microcontrollers available for all kinds of tasks, each one with its unique set of features and capabilities. However, not all of us want to spend time mucking about in C or assembly to learn the intricacies of each different chip. If you prefer the higher planes of Python instead, it’s not impossible to import Python on even the smallest of microcontrollers thanks to MicroPython, which [Rob] shows us in this project based on the ESP32.

[Rob] has been working on a small robot called Marty which uses an ESP32 as its brain, so the small microcontroller is already tasked with WiFi/Bluetooth communications and driving the motors in the robot. Part of the problem of getting Python to run on a platform like this is that MicroPython is designed to be essentially the only thing running on the device at any one point, but since the ESP32 is more powerful than the minimum requirements for MicroPython he wanted to see if he could run more than just Python code. He eventually settled on a “bottum-up” approach to build a library for the platform, rather than implementing MicroPython directly as a firmware image for the ESP32.

The blog post is an interesting take on running Python code on a small platform, and goes into some details with the shortcomings of MicroPython itself which [Rob] ended up working around for this project. He’s also released the source code for his work on his GitHub page. Of course, for a different approach to running Python and C on the same small processor, there are some libraries that accomplish that as well.

A Different Kind Of IKEA Hack: Javascript Price Comparison By Location

November 14, 2020 by 8 Comments

When looking for the best deal, it pays to shop around. When it comes to chain stores, of course, one expects the price to be the same across their retail network. However, where international companies are concerned, occasionally a better deal is just a border crossing away. To investigate the best possible price on IKEA’s flatpacked goods, [Sn0w5t0rm] whipped up a scirpt to make comparisons easy.

The hack consists of a small piece of Javascript that runs in a browser extension like Greasemonkey (Firefox) or Tampermonkey (Chrome). When visiting an IKEA product page, it shows the price of the same item in the alternative country of your choice. Often, significant savings can be had – the SKOGSTA table is €176 cheaper in the Netherlands compared to Belgium.

While the script does require some customization to suit your location, it could nonetheless save you a bundle on some home furnishings if your live near enough to a border. We’d love to see the concept taken further to tease out best prices in a given region for goods from all stores. Similar techniques can net you cheap airfares, too!