Hackaday Podcast 016: 3D Printing With Steel, Molding With Expanded Foam, QUIP-Package Parts, And Aged Solder

April 26, 2019 by Mike Szczys 3 Comments

Join Editors Elliot Williams and Mike Szczys to recap the week in hardware hacking. This episode looks at microfluidics using Shrinky Dinks, expanding foam to build airplane wings, the insidious effect of time on component solder points, and Airsoft BBs used in 3D printing. Finishing out the episode we have an interview with two brothers who started up a successful business in the Shenzhen electronics markets.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)

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3D Printed Tank Track Pops Together With Plastic BB For Hinge

April 20, 2019 by Donald Papp 20 Comments

3D printing is well-suited to cranking out tank tread designs, because the numerous and identical segments required are a great fit for 3D printing’s strengths. The only hitch is the need for fasteners between each of those segments, but [AlwynxJones] has a clever solution that uses plentiful hard plastic spheres (in the form of 6 mm airsoft BBs) as both a fastener and a hinge between each of the 3D printed track segments.

Each segment has hollows made to snugly fit 6 mm BBs (shown as green in the image here) which serve both as fasteners and bearing surfaces. Assembly requires a bit of force to snap everything together, but [AlwynxJones] judges the result worth not having to bother with bolts, wires, or other makeshift fasteners.

Bolts or screws are one option for connecting segments, but those are heavy and can get expensive. Segments of printer filament have been successfully used in other tread designs, though that method requires added work in the form of either pins, or heat deforming the filament ends to form a kind of rivet. This design may be a work in progress, but it seems like a promising and clever approach.

[via Reddit]

The Empire Strikes Back With The ESP8266

February 13, 2019 by Tom Nardi 1 Comment

Like many of us, [Matthew Wentworth] is always looking for a reason to build something. So when he found a 3D model of the “DF.9” laser turret from The Empire Strikes Back intended for Star Wars board games on Thingiverse, he decided it was a perfect ~~excuse~~ opportunity to not only try his hand at remixing an existing 3D design, but adding electronics to it to create something interactive.

As the model was originally intended for a board game, it was obviously quite small. So the first order of business was scaling everything up to twice the original dimensions. As [Matthew] notes, the fact that it still looks so good when expanded by such a large degree is a credit to how detailed the original model is. Once blown up to more useful proportions, he modified the head of the turret as well as the barrel to accept the electronics he planned on grafting into the model.

He created a mount for a standard nine gram servo inside the head of the turret which allows it to rotate, and the barrel got an LED stuck in the end. Both of which are controlled with a NodeMCU ESP8266 development board, allowing [Matthew] to control the direction and intensity of the pew-pew over WiFi. He mentions that in the future he would like to add sound effects that are synchronized to the turret rotation and LED blinking.

For the software side of the project, he used Blynk to quickly build a smartphone interface for the turret. This is the first time he had used Blynk, and reports that outside of a little trial and error, it was some of the easiest code he’s ever written for the Arduino. This is a sentiment we’ve been seeing a lot of recently towards Blynk, and it’s interesting to see how often it shows up in ESP8266 projects now.

Looking ahead [Matthew] says he wants to paint and detail the turret, as the bright orange color scheme probably wouldn’t do terribly well on Hoth. If he can manage the time, he’d also like to add it to the long list of OpenCV-powered turrets that hackers love harassing their friends and family with.

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An Over-engineered LED Sign Board

December 8, 2018 by Inderpreet Singh 10 Comments

Never underestimate the ability of makers in over thinking and over-engineering the simplest of problems and demonstrating human ingenuity. The RGB LED sign made by [Hans and team] over at the [Hackheim hackerspace] in Trondheim is a testament to this fact.

As you would expect, the WS2812 RGB LEDs illuminate the sign. In this particular construction, an individual strip is responsible for each character. Powered by an ESP32 running FreeRTOS, the sign communicates using MQTT and each letter gets a copy of the 6 x 20 framebuffer which represents the color pattern that is expected to be displayed. A task on the ESP32 calculates the color value to be displayed by each LED.

The real question is, how to calibrate the distributed strings of LEDs such that LEDs on adjacent letters of the sign display an extrapolated value? The answer is to use OpenCV to create a map of the LEDs from their two-dimensional layout to a lookup table. The Python script sends a command to illuminate a single LED and the captured image with OpenCV records the position of the signal. This is repeated for all LEDs to generate a map that is used in the ESP32 firmware. How cool is that?

And if you are wondering about the code, it is up on [Github], and we would love to see someone take this up a level. The calibration code, as well as the Remote Client and ESP32 codes, are all there for your hacking pleasure.

Its been a while since we have seen OpenCV in action like with the Motion Tracking Turret and Face Recognition. The possibilities seem endless. Continue reading “An Over-engineered LED Sign Board” →

Reinforce Happy Faces With Marshmallows And Computer Vision

August 14, 2018 by Al Williams 3 Comments

Bing Crosby famously sang “Just let a smile be your umbrella.” George Carlin, though, said, “Let a smile be your umbrella, and you’ll end up with a face full of rain.” [BebBrabyn] probably agrees more with the former and used a Raspberry Pi with Open CV to detect a smile, a feature some digital cameras have had for a long time. This project however doesn’t take a snapshot. It launches a marshmallow using a motor-driven catapult. We wondered if he originally tried lemon drops until too many people failed to catch them properly.

This wouldn’t be a bad project for a young person — as seen in the video below — although you might have to work a bit to duplicate it. The catapult was upcycled from a broken kid’s toy. You might have to run to the toy store or rig something up yourself. Perhaps you could 3D print it or replace it with a trebuchet or compressed air.

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Training The Squirrel Terminator

April 30, 2018 by Tom Nardi 31 Comments

Depending on which hemisphere of the Earth you’re currently reading this from, summer is finally starting to fight its way to the surface. For the more “green” of our readers, that can mean it’s time to start making plans for summer gardening. But as anyone who’s ever planted something edible can tell you, garden pests such as squirrels are fantastically effective at turning all your hard work into a wasteland. Finding ways to keep them away from your crops can be a full-time job, but luckily it’s a job nobody will mind if automation steals from humans.

[Peter Quinn] writes in to tell us about the elaborate lengths he is going to keep bushy-tailed marauders away from his tomatoes this year. Long term he plans on setting up a non-lethal sentry gun to scare them away, but before he can get to that point he needs to perfect the science of automatically targeting his prey. At the same time, he wants to train the system well enough that it won’t fire on humans or other animals such as cats and birds which might visit his garden.

A Raspberry Pi 3 with a cheap webcam is used to surveil the garden and detect motion. When frames containing motion are detected, they are forwarded to a laptop which has enough horsepower to handle the squirrel detection through Darknet YOLO. [Peter] recognizes this isn’t an ideal architecture for real-time targeting of a sentry turret, but it’s good enough for training the system.

Which incidentally is what [Peter] spends the most time explaining on the project’s Hackaday.io page. From the saga of getting the software environment up and running to determining how many pictures of squirrels in his yard he should provide the software for training, it’s an excellent case study in rolling your own image recognition system. After approximately 18 hours of training, he now has a system which is able to pick squirrels out from the foliage. The next step is hooking up the turret.

We’ve covered other automated turrets here on Hackaday, and we’ve seen automated devices for terrifying squirrels before, but this is the first time we’ve seen the concepts mixed.

Firing Bullets Through Propellers

April 25, 2018 by Steven Dufresne 39 Comments

Early airborne combat was more like a drive-by shooting as pilot used handheld firearms to fire upon other aircraft. Whomever could boost firepower and accuracy would have the upper hand and so machine guns were added to planes. But it certainly wasn’t as simple as just bolting one to the chassis.

This was during World War I which spanned 1914 to 1918 and the controllable airplane had been invented a mere eleven years before. Most airplanes still used wooden frames, fabric-covered wings, and external cable bracing. The engineers became pretty inventive, even finding ways to fire bullets through the path of the wooden propeller blades while somehow not tearing them to splinters.

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