Machine-Vision Archer Makes You The Target, If You Dare

June 30, 2021 by 6 Comments

We’ll state right up front that it’s a really, really bad idea to let a robotic archer shoot an apple off of your head. You absolutely should not repeat what you’ll see in the video below, and if you do, the results are all on you.

That said, [Kamal Carter]’s build is pretty darn cool. He wisely chose to use just about the weakest bows you can get, the kind with strings that are basically big, floppy elastic bands that shoot arrows with suction-cup tips and are so harmless that they’re intended for children to play with and you just know they’re going to shoot each other the minute you turn your back no matter what you told them. Target acquisition is the job of an Intel RealSense depth camera, which was used to find targets and calculate the distance to them. An aluminum extrusion frame holds the bow and adjusts its elevation, while a long leadscrew and a servo draw and release the string.

With the running gear sorted, [Kamal] turned to high school physics for calculations such as the spring constant of the bow to determine the arrow’s initial velocity, and the ballistics formula to determine the angle needed to hit the target. And hit it he does — mostly. We’re actually surprised how many on-target shots he got. And yes, he did eventually get it to pull a [William Tell] apple trick — although we couldn’t help but notice from his, ahem, hand posture that he wasn’t exactly filled with self-confidence about where the arrow would end up.

[Kamal] says he drew inspiration both from [Mark Rober]’s dart-catching dartboard and [Shane Wighton]’s self-dunking basketball hoop for this build. We’d say his results put in him good standing with the skill-optional sports community.

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PinThing Mechanizes Pin Art

June 30, 2021 by 11 Comments

Pin art is one of those things that simply cannot be left alone if it’s within arms reach, and inevitably end up with a hand or face imprint. [hugs] is also fascinated by them, so he designed the PinThing, a mechanized pin art display.

The PinThing pin diameters are much larger than standard pin art, but this is to fit small geared DC motors. Each pin is a short 3D-printed lead screw mechanism. The motors are driven with a stack of motor driver shields on top of an Arduino Uno, which uses Firmata to receive instructions over serial from a Node.js app using the Johnny-Five library. This may be a simple 3×5 proof of concept, but then it could be used for everything from displays to interactive table surfaces.

One of the challenges with pixelated mechanical displays like this, the inFORM from MIT, or even flip dot displays, are the costs in actuators and driver electronics. A small 10×10 array requires 100 motors and drivers, which quickly adds up as you expand, even if individual components are quite cheap.

If you are willing to sacrifice instantaneous response from each pixel, you can use a mechanical multiplexer. It consists of some sort of moving carriage behind the display with mounted actuators, so you’ll only need an actuator per row, not for every pin. This also means the pins can be closer together since the actuators can be staggered on the carriage.

PinThing project was an entry to the Rethink Displays Challenge of the 2021 Hackaday Prize, for which the finalists were just announced.

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Adding A Gentle Touch To Prosthetic Limbs With Somatosensory Stimulation

June 30, 2021 by 5 Comments

When Nathan Copeland suffered a car accident in 2004, damage to his spinal cord at the C5/C6 level resulted in tetraplegic paralysis. This left him initially at the age of 18 years old to consider a life without the use of his arms or legs, until he got selected in 2014 for a study at the University of Pittsburgh involving the controlling of a robotic limb using nothing but one’s mind and a BCI.

While this approach, as replicated in various other studies, works well enough for simple tasks, it comes with the major caveat that while it’s possible to control this robotic limb, there is no feedback from it. Normally when we try to for example grab an object with our hand, we are aware of the motion of our arm and hand, until the moment when our fingers touch the object which we’re reaching for.

In the case of these robotic limbs, the only form of feedback was of the visual type, where the user had to look at the arm and correct its action based on the observation of its position. Obviously this is far from ideal, which is why Nathan hadn’t just been implanted with Utah arrays that read out his motor cortex, but also arrays which connected to his somatosensory cortex.

As covered in a paper by Flesher et al. in Nature, by stimulating the somatosensory cortex, Nathan has over the past few years regained a large part of the sensation in his arm and hand back, even if they’re now a robotic limb. This raises the question of how complicated this approach is, and whether we can expect it to become a common feature of prosthetic limbs before long. Continue reading “Adding A Gentle Touch To Prosthetic Limbs With Somatosensory Stimulation” →

Astronomic Patio Light Timer

June 30, 2021 by 21 Comments

Not satisfied with the handheld remote control for his outdoor patio lights, [timabram] decided to build an automatic timer using an ESP8266. He’s using a set of string lights from Costco, but as you dig into his project you’ll see the method he uses can be applied to almost any set of lights that have a remote.

He does this by connecting GPIO pins from the ESP8266 GPIO into the remote control in order to simulate a user pressing the button. Both boards are packaged together in a 3D-printed enclosure that utilizes the front portion of the remote control, so that manual operation is still possible.

His firmware gets the date and time from an NTP server, and then makes an API call to an online service that returns the local sunrise and sunset times for a specific location. He tries to minimize the power consumption by experimenting with different intervals to wakeup from deep sleep and ping the time server. But in the end, he realizes the RF remote control carries quite some distance, and installed the unit inside a closet where it could be powered by adaptors connected to the mains.

We wondered how the remote control knows if the lights are on or off, and [timabram] notes this is a shortcoming which could be addressed in a future version. If you’ve ever seen a mechanical version of an astronomic timer switch, packed full of gears and dials and setting pins, you can really appreciate a no-moving-parts solutions like this project. If you want to make one that doesn’t use the internet, check out this Arduino-based solution that we wrote about back in 2013.

China’s Mars Rover Goes Exploring

June 30, 2021 by 20 Comments

China’s space program has big goals and is already starting to achieve them. Recently, the China National Space Administration has landed its first rover on Mars, and begun to explore the surface of the red planet.

It’s a huge step, and something only previously achieved successfully by NASA. Let’s take a look at the Chinese project, its goals, and see how it compares to the American rovers that have also roamed so far away.

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Handheld Hackintosh Runs Mac OS On LattePanda

June 30, 2021 by 16 Comments

We’ve seen a huge influx of bespoke portable computers over the last couple of years thanks to availability of increasingly powerful single-board computers. The vast majority of these have been ARM powered using something like the Raspberry Pi 4, and naturally, run Linux. Only a handful have run on x86 hardware, usually because whoever built it wanted to be able to run Windows.

But this handheld x86 Hackintosh running the latest Mac OS on the LattePanda Alpha is truly something unique. Creator [iketsj] claims it to be a world’s first, and after a bit of searching, we’re inclined to agree. While others have installed Mac OS on the LattePanda to create Hackintosh laptops, this would indeed appear to be the first handheld computer to utilize this particular hardware and software blend.

Like other custom portables we’be seen, this one starts with a 3D printed enclosure. The overall design reminds us a bit of the YARH.IO we covered last year, and even borrows the trick of reusing the membrane and PCB of one of those miniature keyboard/pointer combos. Which in this case ends up being especially important, as in keeping with Apple’s own portable Mac OS machines, the screen on this handheld doesn’t support touch.

We especially like how the integrated Arduino on the LattePanda is being used in conjunction with some MOSFETs to control power to the handheld’s LCD, keyboard, and fans. While it sounds like the fans are currently running at full throttle, [iketsj] mentions he does intend on adding automatic speed control in the future. A dedicated “chassis controller” like this makes a lot of sense, and is something we imagine will only become more common as these portable builds become increasingly complex.

Now that we’ve seen a custom portable computer running Mac OS, are we due to see a whole new wave of cyberdecks sporting Cupertino’s software in the future? Maybe not. As [iketsj] points out at the end of this video, Apple’s switch from x86 to their own in-house silicon will almost certainly mean the death of the Hackintosh project within the next few years, bringing a fascinating era of computer hacking to a close.

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Robotic Ball-Bouncing Platform Learns New Tricks

June 30, 2021 by 11 Comments

[T-Kuhn]’s Octo-Bouncer platform has learned some new tricks since we saw it last. If you haven’t seen it before, this device uses computer vision from a camera mounted underneath its thick, clear acrylic platform to track a ball in 3D space, and make the necessary (and minute) adjustments needed to control the ball’s movements with a robotic platform in real time.

We loved the Octo-Bouncer’s mesmerizing action when we saw it last, and it’s only gotten better. Not only is there a whole new custom ball detection algorithm that [T-Kuhn] explains in detail, there are also now visualizations of both the ball’s position as well as the plate movements. There’s still one small mystery, however. Every now and again, [T-Kuhn] says that the ball will bounce in an unexpected direction. It doesn’t seem to be a bug related to the platform itself, but [T-Kuhn] has a suspicion. Since contact between the ball and platform is where all the control comes from, and the ball and platform touch only very little during a bounce, it’s possible that bits of dust (or perhaps even tiny imperfections on the ball’s surface itself) might be to blame. Regardless, it doesn’t detract from the device’s mesmerizing performance.

Design files and source code are available on the project’s GitHub repository for those who’d like a closer look. It’s pretty trippy watching the demonstration video because there is so much going on at once; you can check it out just below the page break.

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