The Fun Is On The Christmas Tree With This Playable Duck Hunt Decoration

‘Tis the season for leftovers, be they food, regifted presents, or the decorations left behind in the wake of the festivities. Not to mention the late tips we get for holiday-themed builds, like this Duck Hunt ornament that’s completely playable.

Details are sparse in [wermy]’s video below, but there’s enough there to get the gist. The game is based on the Nintendo classic, where animated ducks fly across the screen and act as targets for a light pistol. Translating that to something suitable for decorating a Christmas tree meant adding an Arduino and an IR LED to the original NES light pistol, and building a base station with a Feather and a small LCD screen into a case that looks like [The Simpsons] TV. An LED on each 3d-printed duck target lights in turn, prompting you to blast it with the gun. An IR sensor on each duck registers hits, while the familiar sound effects are generated by the base, which also displays the score. Given a background of festive blinkenlights, it’s harder than it sounds – see it in action briefly below.

[wermy] has done some interesting builds before, like a RetroPie in an Altoids tin and a spooky string of eyes for Halloween. We hope he’ll come through with a more detailed build video for this project at some point – we’re particularly interested in those beautiful multi-color 3D-prints.

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Death To All Coca Cola Cans With This Miniature Arduino Powered Cannon

[MJKZZ] sends in this entertaining little tutorial on building a small automated cannon out of a syringe.

He starts the build off by modifying an arc lighter, the fancy kind one might use to light a fire on a windy day, so that it can be controlled by a micro-controller. The arc is moved to the needle end of the syringe with a careful application of wires and hot glue. When the syringe is filled with a bit of alcohol and the original plunger is pressed back in a small spark will send it flying back out in a very satisfying fashion.

Of course it wouldn’t be a proper hack without an Arduino added on for no reason other than the joy of doing so. [MKJZZ] adds an ultrasonic sensor into the mix which, when triggered appropriately by an invading object fires the arc lighter using a reed relay.

He demonstrates the build by eliminating an intruding coke can on his work bench. You can see it in the video after the break. All in all a very fun hack.

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Robotic Skin Sees When (and How) You’re Touching It

Cameras are getting less and less conspicuous. Now they’re hiding under the skin of robots.

A team of researchers from ETH Zurich in Switzerland have recently created a multi-camera optical tactile sensor that is able to monitor the space around it based on contact force distribution. The sensor uses a stack up involving a camera, LEDs, and three layers of silicone to optically detect any disturbance of the skin.

The scheme is modular and in this example uses four cameras but can be scaled up from there. During manufacture, the camera and LED circuit boards are placed and a layer of firm silicone is poured to about 5 mm in thickness. Next a 2 mm layer doped with spherical particles is poured before the final 1.5 mm layer of black silicone is poured. The cameras track the particles as they move and use the information to infer the deformation of the material and the force applied to it. The sensor is also able to reconstruct the forces causing the deformation and create a contact force distribution. The demo uses fairly inexpensive cameras — Raspberry Pi cameras monitored by an NVIDIA Jetson Nano Developer Kit — that in total provide about 65,000 pixels of resolution.

Apart from just providing more information about the forces applied to a surface, the sensor also has a larger contact surface and is thinner than other camera-based systems since it doesn’t require the use of reflective components. It regularly recalibrates itself based on a convolutional neural network pre-trained with data from three cameras and updated with data from all four cameras. Possible future applications include soft robotics, improving touch-based sensing with the aid of computer vision algorithms.

While self-aware robotic skins may not be on the market quite so soon, this certainly opens the possibility for robots that can detect when too much force is being applied to their structures — the machine equivalent sensation to pain.

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Hackaday Links: November 17, 2019

Friday, November 15, 2019 – PASADENA. The 2019 Hackaday Superconference is getting into high gear as I write this. Sitting in the Supplyframe HQ outside the registration desk is endlessly entertaining, as attendees pour in and get their swag bags and badges. It’s like watching a parade of luminaries from the hardware hacking world, and everyone looks like they came ready to work. The workshops are starting, the SMD soldering challenge is underway, and every nook and cranny seems to have someone hunched over the amazing Hackaday Superconference badge, trying to turn it into something even more amazing. The talks start on Saturday, and if you’re not one of the lucky hundreds here this weekend, make sure you tune into the livestream so you don’t miss any of the action.

The day when the average person is able to shoot something out of the sky with a laser is apparently here. Pablo, who lives in Argentina, has beeing keeping tabs on the mass protests going on in neighboring Chile. Huge crowds have been gathering regularly over the last few weeks to protest inequality. The crowd gathered in the capital city of Santiago on Wednesday night took issue with the sudden appearance of a police UAV overhead. In an impressive feat of cooperation, they trained 40 to 50 green laser pointers on the offending drone. The videos showing the green beams lancing through the air are quite amazing, and even more amazing is the fact that the drone was apparently downed by the lasers. Whether it was blinding the operator through the FPV camera or if the accumulated heat of dozens of lasers caused some kind of damage to the drone is hard to say, and we’d guess that the drone was not treated too kindly by the protestors when it landed in the midsts, so there’s likely not much left of the craft to do a forensic analysis, which is a pity. We will note that the protestors also trained their lasers on a police helicopter, an act that’s extremely dangerous to the human pilots which we can’t condone.

In news that should shock literally nobody, Chris Petrich reports that there’s a pretty good chance the DS18B20 temperature sensor chips you have in your parts bin are counterfeits. Almost all of the 500 sensors he purchased from two dozen vendors on eBay tested as fakes. His Github readme has an extensive list that lumps the counterfeits into four categories of fake-ness, with issues ranging from inaccurate temperature offsets to sensors without EEPROM that don’t work with parasitic power. What’s worse, a lot of the fakes test almost-sorta like authentic chips, meaning that they may work in your design, but that you’re clearly not getting what you paid for. The short story to telling real chips from the fakes is that Maxim chips have laser-etched markings, while the imposters sport printed numbers. If you need the real deal, Chris suggests sticking with reputable suppliers with validated supply chains. Caveat emptor.

A few weeks back we posted a link to the NXP Homebrew RF Design Challenge, which tasked participants to build something cool with NXP’s new LDMOS RF power transistors. The three winners of the challenge were just announced, and we’re proud to see that Razvan’s wonderfully engineered broadband RF power amp, which we recently featured, won second place. First place went to Jim Veatch for another broadband amp that can be built for $80 using an off-the-shelf CPU heatsink for thermal management. Third prize was awarded to a team lead by Weston Braun, which came up with a switch-mode RF amp for the plasma cavity for micro-thrusters for CubeSats, adorably named the Pocket Rocket. We’ve featured similar thrusters recently, and we’ll be doing a Hack Chat on the topic in December. Congratulations to the winners for their excellent designs.

Simple Seismic Sensor Makes Earthquake Detection Personal

When an earthquake strikes, it’s usually hard to miss. At least that’s the case with the big ones; the dozens or hundreds of little quakes that go largely unnoticed every day are interesting too, and make sense to track. That’s usually left to the professionals, with racks of sensitive equipment and a far-flung network of seismic sensors. That doesn’t mean you can’t keep track of doings below your feet yourself, with something like this DIY seismograph.

Technically, what [Alex] built is better called a “seismic detector” since it’s not calibrated in any way. It’s just a simple sensor for detecting ground vibrations, whether they be due to passing trucks or The Big One. [Alex] lives in California, wedged between the Hayward, Calaveras, and San Andreas faults in San Jose, so there is plenty of opportunity for testing his device. The business end is a simple pendulum sensor, with a heavy metal bob hanging from a long wire inside a length of plastic pipe. Positioned close to the bob is a copper plate; the bob and the plate form an air-dielectric variable capacitor that controls the frequency of a simple 555 oscillator. The frequency is measured by a PIC microcontroller and sent to a Raspberry Pi, which displays the data on a graph. You can check in on real-time seismic activity in San Jose using the link above, or check out historical quakes, like the 7.1 magnitude Ridgecrest quake in July. [Alex]’s sensor is sensitive enough to pick up recent quakes in Peru, Fiji, and Nevada, and he even has some examples of visualizing the Earth’s core using data from the sensor. How cool is that?

We’ve seen other seismic detectors before, like this piezo-based device, or even one made from toilet parts. We like the simplicity of the capacitive sensor [Alex] used, though.

Fitness Tracker Hacked Into Optical Density Meter

What do fitness trackers have to do with bacterial cultures in the lab? Absolutely nothing, unless and until someone turns a fitness band into a general-purpose optical densitometer for the lab.

This is one of those stories that shows that you never know from where inspiration is going to come. [Chinna Devarapu] learned that as a result of playing around with cheap fitness bands, specifically an ID107HR. A community has built up around hacking these bands; we featured a similar band that was turned into an EEG. With some help, [Chinna] was able to reflash the microcontroller and program it in the Arduino IDE, and began looking for a mission for the sensor-laden platform.

He settled on building a continuous optical densitometer for his biology colleagues. Bacterial cultures become increasingly turbid as the grow, and measuring the optical density (OD) of a culture is a common way to monitor its growth phase. This is usually done by sucking up a bit of the culture to measure, but [Chinna] and his team were able to use the hacked fitness band’s heartrate sensor to measure the OD on the fly. The tracker fits in a 3D-printed holder where an LED can shine through the growing culture; the sensor’s photodiode measures the amount of light getting through and the raw data is available via the tracker’s Bluetooth. The whole thing can be built for less than $20, and the plans have been completely open-sourced.

We really like the idea of turning these fitness bands into something completely different. With the capabilities these things pack into such a cheap and compact package, they should start turning up in more and more projects.

Cheap Sensors And An SDR Monitor Conditions In This Filament Drying Farm

We don’t know where [Scott M. Baker] calls home, but it must be a pretty humid place indeed. After all, he has invested quite a bit in fancy vacuum storage containers to keep his 3D-printer filament dry, with the result being this sensor-laden filament drying farm.

[Scott] wasn’t content to just use these PrintDry containers without knowing what’s going on inside. After a little cleaning and lube to get all the containers working, he set about building the sensors. He settled on a wireless system, with each container getting a BME280 temperature/humidity/pressure sensor and an SYN115 315-MHz ISM band transmitter module. These go with an ATtiny85 into a compact 3D-printed case holding a little silica desiccant. The transmitters are programmed to comply with ISM-band regulations – no need to run afoul of those rules – while the receiver is just an SDR dongle and a Raspberry Pi running rtl_433. The long-ish video below details design and construction.

The idea behind these vacuum containers would seem to be to pull out humid air and prevent it from coming back in. But as [Scott] quickly learned from his telemetry, following the instructions results in the equivalent atmospheric pressure of only about 2700′ (823 meters) elevation – not exactly a hard vacuum. But as [Scott] points out, it’s enough to get a nice, tight seal, and his numbers show a lowered and constant relative humidity over time.

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