Squares of sample materials placed on the laser bed awaiting the sensing head

Smart Laser Cutter Ad-on Detects Material Optically

Come on now, admit it. You’ve done it. We’ve done it. You know — you were really sure that sheet of plastic stock you found lying around the hackerspace was acrylic right? You dialled in the settings, loaded the design, set the focus and pushed the little green ‘start’ button. Lots of black smoke, fire, and general badness ensued as you lunged for the red ‘stop’ button, before lifting the lid to work out how you’re going to clean this one up.

That was not acrylic. That was polycarbonate.

What you need is the latest gadget from MIT: SensiCut: A smart laser cutter system that detects different materials automatically.

The technique makes use of so-called ‘speckle imaging’ where a material illuminated by a laser will produce a unique pattern of reflected spots, or speckles into a camera. By training a deep neural model with a large set of samples, it was found possible to detect up to 30 types of material with 98% accuracy.

The pre-baked model runs on a Raspberry PI zero with an off-the-shelf camera all powered from a power bank. This allows the whole assembly to simply drop onto an existing laser cutter head, with no wiring needed.

Even if you’re a seasoned laser cutter user, with a well-controlled stock pile, the peace-of-mind this could give would definitely be worth the effort. A more detailed description and more videos may be found by reading the full paper. Here’s hoping they release the system as open source, one day in the not-to-distant future. If not, then, you know what to do :)

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the introduction page of "a summary of electronics"

This Electronics Overview Guides New Hackers In The Right Direction

Many of us don’t have a formal background to build off when taking on new hacks, we have had to teach ourselves complex concepts and learn by doing (or more commonly, by failing). To help new hackers get off the ground a bit easier, [PhilosopherFar3847] created a fantastic starter’s resource on electronics, The Electroagenda Summary of Electronics.

[PhilosipherFar3847] created Electroagenda with the goal of helping amateurs, students, and professionals alike better understand electronics. The Summary of Electronics, one of the more recent additions to the website, is split across 26 sections each breaking down a different electrical concept into easy-to-understand facts with no math or unfamiliar jargon. The summary covers a broad range of electronics, from simple passive components and their uses, up to the basic operating concepts of a microcontroller.

While this resource on its own will not be enough to get a fledgling hacker started making cool circuits, it does provide a very important skill; knowing how to ask the right questions. This base of knowledge provides enough context and keywords to better articulate a challenge and Google-fu a bit more effectively.

Are you the aforementioned fledgling hacker, looking to learn more? check out these nifty logic gates you can plug into each other to build a basic circuit.

[via r/diyelectronics]

Homebrew Sounder Maps The Depths In Depth

For those who like to muck around in boats, there’s enough to worry about without wondering if you’re going to run aground. And there’s really no way to know that other than to work from charts that show you exactly what lies beneath. But what does one do for places where no such charts exist? Easy — make your own homebrew water depth logger.

Thankfully, gone are the days when an able seaman would manually deploy the sounding line and call out the depth to the bottom. [Neumi]’s sounding rig uses an off-the-shelf sonar depth sounder, one with NMEA, or National Marine Electronic Association, output. Combined with a GPS module and an Arduino with an SD card, the rig can keep track not only of how much water is below it, but exactly where the measurement point is. The whole thing is rigged up to an inflatable dinghy which lets it slowly ply the confines of a small marina, working in and out of the nooks and crannies. A bit of Python and matplotlib stitches that data together into a bathymetric map of the harbor, with pretty fine detail. The chart also takes the tides into account, as the water level varies quite a bit over the four hours it takes to gather all the data. See it in action in the video after the hop.

There’s something cool about revealing the mysteries of the deep, even if they’re not that deep. Want to go a little deeper? We’ve seen that before too.

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M4 Breadstick Is A Tasty Prototyping Alternative

What does “breadboard-friendly” mean to you? It’s become a game of minimum viability. Sure, it fits in the breadboard, but are there any accessible tie points left for wires and components? What good is a development board if you can’t easily prototype with it?

A few years ago, [Michael Rangen] set out to change all of that by creating a long and skinny development board that spaces out the I/O pins and simplifies wiring, making every circuit beautiful and easier to take in visually. The current version is an adaptation of Adafruit’s ItsyBitsy M4 Express. It has 20 I/O pins, all spread out along the length and numbered around the horn like an IC. [Michael] dipped this breadstick in 24 tiny RGB LEDs, all of which are on a dedicated com bus.

We think this is a great idea that will definitely make microcontrollers more hackable. This type of layout would make checking students’ work a breeze, and you can make tidy prototypes with it yourself after class. Today the board runs CircuitPython, and it will be able to run Arduino in the future.

This ESP socket may not leave quite as many tie points open, but it’s way easier than soldering header to it.

Tiny ESP32 Strider Walks The Walk

Wheels might be the simplest method of locomotion for robots, but walkers are infinitely more satisfying to watch. This is certainly the case for [Chen Liang’s] tiny Strider walker controlled by a ESP32 camera board.

The Strider mechanism might look similar to Strandbeest walkers, but it lifts its feet higher, allowing it to traverse rougher terrain. [Chen]’s little 3D printed version is driven by a pair of geared N20 motors, with three legs on each side. The ESP32 camera board allows for control and an FPV video feed using WiFi, with power coming from a 14500 LiFePO4 battery. The width required by the motors, leg mechanisms, and bearings means the robot is quite wide, to the point that it could get stuck on something that’s outside the camera’s field of view. [Chen] is working to make it narrower by using continuous rotation servos and a wire drive shaft.

We’ve seen no shortage or riffs on the many-legged walkers, like the TrotBot and Strider mechanism developed by [Wade] and [Ben Vagle], and their website is an excellent resource for prospective builders.

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Small Scale Mad Max: Danny Huynh’s Dystopian Animatronics

The hacker spirit is always alive and well in post-apocalyptic fiction, as characters throw together contraptions from whatever junk they can find. While these might not always be practical or possible in reality, their primary purpose is usually to look the part. This is definitely the case for [Danny Huynh]’s post-apocalyptic animatronic creations, which look like they can slot straight into Mad Max or Fallout.

[Danny] is an avid RC enthusiast, so many of the models are highly customized off-the-shelf RC cars. However, it’s the lifelike moving characters in these models that really catch the eye. Their hands and feet move with the steering and throttle, and in the motorcycle builds they will often lean with the turns. Other notable builds include a hexapedal taxi and a couple of animatronic bands.

All the vehicle builds are electric, but it looks like [Danny] often includes an audio module to simulate a roaring engine. He makes extensive use of servos and linkages for character movement, with wiring and electronics carefully hidden by paint or bodywork.

With all the CGI technology available today, great animatronic builds like an eerily lifelike heart, or a talking Nikola Tesla are all the more impressive to see.

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Lightning Detector Keeps A Tally

Lightning is one of the great forces of nature. The huge releases of electricity release detectable electromagnetic emissions, as you might expect. The team at the [LVL1 Hackerspace] put together a lightning detector of their own; one which keeps count of the number of discharges in the atmosphere.

The device consists of a typical tank circuit tuned to 300kHz, paired with a small telescopic antenna. Lightning strikes in the area induce an oscillation in the circuit which is amplified and then detected by an Arduino. The Arduino measures the voltage of the pulse, which is proportional to the magnitude of the signal detected. A ring of Neopixel LEDs are then switched on relative to the intensity of the signal. Additionally, when not actively detecting strikes, the Arduino instead uses the LEDs to display the current time and a binary count of the number of strikes detected since it has been running.

It’s a simple build, and one that would serve as a great introduction into the world of addressable LEDs and environmental monitoring. If you’d like to go about it another way, you can detect lightning with an SDR, too!