Misc Hacks

3864 Articles

Annoying Cicada Magnet Is Nonetheless Authentic

March 18, 2023 by 15 Comments

We’ve all heard of those chirper devices that randomly make annoying noises for no other reason than sending people insane. This project from [Kousuke Saito] brings altogether more art to this idea, while still being quite annoying indeed.

The build is essentially a replica cicada. [Saito] was inspired to build the device as the sounds of the insect remind him fondly of the summer. His design consists of a 3D-printed housing that roughly approximates something like a cicada, with two wings attached to a central body. In this case, the layer lines of the 3D print actually added to the realism of the ersatz insect The housing is nicely painted to serve as an adequate simulacra to those who aren’t up on their entomology.

Inside, there’s an ATTiny 85 paired with an MP3 playback module and a small speaker. It’s charged with reproducing the noise of various cicadas. It’s setup with an ingenious mechanism to switch it on. There are magnets installed in the base which allow it to stick to metallic objects. There’s also a switch in the bottom of the device. When it magnetically attaches to a surface, that switch is depressed, and the cicada starts playing, well… cicada noises. [Saito] notes that a patent has been secured for the idea.

We’ve seen other cicada-themed projects before, astoundingly. Video after the break.

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Calibrating Thermal Cameras With Hot Patterned Objects

March 18, 2023 by 5 Comments

Thermal cameras are great if you want to get an idea of what’s hot and what’s not. If you want to use a thermal camera for certain machine vision tasks, though, you generally need to do a geometric calibration to understand what the camera is seeing and correct for lens distortion. [Henry Zhang] has shared various methods of doing just that.

It’s all about generating a geometrically-regular thermal pattern.

To calibrate a thermal camera, first you need a thermal pattern. This is like typical test image for a camera or screen, but with temperatures instead of colors. [Henry] explains several methods for doing this. One involves using a grid of nichrome wires to create a thermal pattern for calibration purposes. Another uses discs of cold aluminium inserted into a foam board. Even a simple checkerboard can work, with the black spaces heating up more from ambient sunlight than their neighbouring white spots. [Henry] then explains the mathematical techniques used for calibrating based on these patterns.

It’s a useful primer on the topic if you’re working with thermal camera systems. We’ve looked at some other interesting machine vision topics before, too. If you’ve got any great thermal imaging tips of your own, don’t hesitate to drop us a line!

 

A solar-powered device with a small LCD screen

Low Power Challenge: LCD Solar Creatures Live On Sunlight, Sleep At Night

March 13, 2023 by 8 Comments

With all those e-paper based projects doing the rounds these days, including in our Low Power Challenge, you’d almost forget that monochrome LCDs were the original ultra-low-power display. Without them, we wouldn’t have had watches, calculators and handheld games operating off button cell batteries or tiny solar panels back in the ’80s and ’90s. [Gabor] decided to build a set of gadgets with a 1990s LCD aesthetic, called LCD Solar Creatures. These cute little beasts live on nothing but solar power and provide some amusing animations on a classic seven-segment LCD screen.

The Creatures’ activity depends entirely on the amount of power that’s available to them. If their supercapacitors dip below 3.3 V, their micros enter a deep sleep state and do nothing except briefly flash an LED every now and then as a sign of life. When light hits the solar panel, the supercaps are charged up and the Creatures come to life and display a few basic stats. Once the caps hit 4.1 V, they really start their day and run a few programs, including a Game of Life-style simulation and an animation of Euclidean rhythms. Continue reading “Low Power Challenge: LCD Solar Creatures Live On Sunlight, Sleep At Night” →

Quick And Dirty Microscope Motion Control For Focus Stacking

March 11, 2023 by 4 Comments

If you’ve spent much time looking through a microscope, you know that their narrow depth of field can be a bit challenging to deal with. Most microscopes are designed to only have a very thin slice of the specimen in focus, so looking at anything above or below that plane requires a focus adjustment. It’s tedious and fussy, and that makes it a perfect target for automation.

The goal behind [ItMightBeWorse]’s microscope mods is “focus stacking,” a technique where multiple images of the same sample taken at different focal planes can be stitched together so that everything appears to be in focus. Rather than twist knobs and take pictures manually, he built a simpler Arduino-based rig to do the job for him. Focus control is through a small stepper motor connected to the fine focus knob of the scope, while the DSLR camera shutter is triggered through a simple relay board. There’s also lighting control, with an RGB LED ring light that can change both the light level on the sample as well as the tint.

The code is very simple, and the setup is quite temporary looking, but the results are pretty impressive. We could do without the extreme closeup of that tick — nasty little arachnids — but the ant at the end of the video below has some interesting details. [ItMightBeWorse] doesn’t mention how the actual stacking is being done, but this CNC-based focus stacking project mentions a few utilities that take help with the post-processing.

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Bode Plot Un-Lecture

March 8, 2023 by 4 Comments

[Rolinychupetin] insists that his recent video is not a lecture but actually a “recitation” about Bode plots. That may be, but it is still worth a watch if you want to learn more about the topic. You can see the video below.

If you haven’t run into Bode plots before, they are simple plots of magnitude or phase vs. frequency, usually plotted on a log scale. Named after Bell Lab’s [Hendrik Wade Bode], they are useful for understanding filters or anything with a frequency response.

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Tidy Breadboard Uses Banana Bread

February 20, 2023 by 21 Comments

Self-described passionate maker in the electronics and 3D printing world, [Jakob], aka [testudor], was getting frustrated trying to connect banana plugs to solderless breadboards. Project Banana Bread was born — small banana jack adaptors and a companion tray with pockets to hold up to six modules.

The base in the photo is made from 5083 aluminum, machined on a homemade CNC router. But design files for a yet-to-be-tested 3D printer version are available as well. As can happen, he strayed from the original goal of solving the banana jack issue, and also cranked out a USB-serial port and a blank template module for any custom interfaces folks may want to implement.

If it is only power connections you are interested in, we covered the Open Power project back in 2019. And also don’t forget the mother of all breadboards, this 1960s behemoth we wrote about last year. What kinds of breadboard interface modules do you find most useful? Let us know in the comments below.

 

DIY Mini Fridge Is Pure Brilliance In Foam

February 18, 2023 by 54 Comments

There’s nothing more pleasing on a hot day than an ice-cold beverage. While the vast majority of us have a fridge in the kitchen, sometimes it’s desirable to have a further fridge in the lab, games room, or workshop. To that end, you may find value in this ultra-cheap, low-cost DIY fridge build from [Handy_Bear].

Like many tiny fridge builds, this design eschews complex gas-cycle refrigeration techniques for simple Peltier modules. These are devices that have one cold side and one hot side, because they move heat when electricity is applied. This build uses a Peltier module fitted with a fan to better shift away heat from the hot side, improving the module’s cooling ability.

The “fridge” itself is assembled out of thick XPS insulation foam. A hot wire cutter was used to cut several slabs which were then assembled using hot glue. The Peltier module is installed on the back, at the top of the fridge. Thus, air which is cooled in this area will then travel down through the rest of the fridge’s cavity. [Handy_Bear] also goes over how to produce a working hinge and a gasket for the door, which helps with ease-of-use and efficiency. As a nice touch, a set of 12V LED lights are also installed inside, which light when the door is open. Just like the real thing!

The final build is noisy, slow to cool down, and it uses 60 watts of power to cool down just two regulation-sized sodas. Notably, you could fit two standard NATO smoke grenades in the same space, as they’re almost-identically sized (ask us how we know). However, smoke grenades don’t usually need to be refrigerated.

None of that means it isn’t fun though! Plus, [Handy_Bear] notes that adding a second Peltier would greatly aid the fridge’s ability to quickly chill your grenades sodas. You might even like to explore the use of special fan designs to make the fridge even quieter! Video after the break.

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