3D Printed ESP8266 TV Is A Blast From The Past

We’ve often said that one of the best applications for desktop 3D printing is the production of custom enclosures, but you certainly aren’t limited to an extruded version of the classic Radio Shack project box. As [Marcello Milone] shows with this very clever retro TV enclosure for the Wemos D1 Mini, 3D printing means your imagination is the only limit when it comes to how you want to package up your latest creation.

As nice as the printed parts are, it’s the little details that really sell the look. [Marcello] has bent a piece of copper wire into a circle to make a faux antenna with vintage flair, and while the ESP is connecting to the WiFi network, it even shows an old school TV test pattern on its 1.8″ TFT display.

In the video after the break you can see the device go through its startup routine, and while displaying the Hackaday Wrencher at boot might not be strictly on theme…we’ll allow it.

While you could certainly use this little enclosure for whatever ESP project you had in mind, [Marcello] says he’s building a distributed environmental monitoring network using HTU21D temperature and humidity sensors. It sounds like he’s still working on the software side of things though, so hopefully he posts an update when the functionality is fully realized.

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Home Monitoring, Without All The Sensors

Smart homes come with a lot of perks, not least among which is the ability to monitor the goings-on in your home, track them, and make trends. Each piece of monitoring equipment, such as sensors or cameras, is another set of wires that needs to be run and another “thing” that needs to be maintained on your system. There are sometimes clever ways of avoiding sensors, though, while still retaining the usefulness of having them.

In this build, [squix78] uses existing sensors for electricity metering that he already had in order to alert him when his oven is pre-heated. The sensor is a Shelly 3EM, and the way that it interfaces with his home automation is by realizing that his electric oven will stop delivering electricity to the heating elements once it has reached the desired temperature. He is able to monitor the sudden dramatic decrease in electricity demand at his house with the home controller, and use that decrease to alert him to the fact that his oven is ready without having to install something extra like a temperature sensor.

While this particular sensor may only be available in some parts of Europe, we presume the idea would hold out across many different sensors and even other devices. Even a small machine learning device should be able to tell what loads are coming on at what times, and then be programmed to perform functions based on that data.

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Slipping Sheets Map Multiple Bends In This Ingenious Flex Sensor

When thoughts turn to measuring the degree to which something bends, it’s pretty likely that strain gauges or some kind of encoders on a linkage come to mind. Things could be much simpler in the world of flex measurement, though, if [Fereshteh Shahmiri] and [Paul H. Dietz]’s capacitive multi-bend flex sensor catches on.

This is one of those ideas that seems so obvious that you don’t know why it hasn’t been tried before. The basic idea is to leverage the geometry of layered materials that slip past each other when bent. Think of the way the pages of a hardbound book feather out when you open it, and you’ll get the idea. In the case of the ShArc (“Shift Arc”) sensor, the front and back covers of the book are flexible PCBs with a series of overlapping pads. Between these PCBs are a number of plain polyimide spacer strips. All the strips of the sensor are anchored at one end, and everything is held together with an elastic sleeve. As the ShArc is bent, the positions of the electrodes on the top and bottom layers shift relative to each other, changing the capacitance across them. From the capacitance measurements and the known position of each pad, a microcontroller can easily calculate the bend radius at each point and infer the curvature of the whole strip.

The video below shows how the ShArc works, as well as several applications for the technology. The obvious use as a flex sensor for the human hand is most impressive — it could vastly simplify [Will Cogley]’s biomimetic hand controller — but such sensors could be put to work in any system that bends. And as a bonus, it looks pretty simple to build one at home.

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A Broken Inductor As A Bike Chain Sensor

If you have ever broken the ferrite core of an inductor, you’ll probably sympathize with [Oliver Mattos]. He accidentally stood on a ferrite-cored component, breaking it and rendering it useless. But utility is in the eye of the beholder, and instead of throwing it away he’s repurposed it as a chain sensor for his electric bicycle.

The broken inductor was positioned on the rear frame of the machine such that the chain passed through the area where the broken half of its core would once have been. As each link passes through the magnetic field it causes the inductance to change, and from this the speed, direction, and tension of the chain can be read.

Adding a 180 nF capacitor in parallel with the inductor creates a tuned circuit, and measuring the inductance is as straightforward as firing a single pulse at it and measuring the time it takes to go negative. Chain speed can be read by sensing the change in inductance as each link passes, tension by sensing the change in inductance as the chain is closer or further away, and direction by whether the chain is slack or not. It’s an ingenious and simple solution to measuring a bicycle chain, and we like it.

A lot of bicycle measurement systems have passed our way over the years, but it’s fair to say they have been more concerned with displays than sensors.

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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