Author Archives: Donald Papp

Spring-Loaded Bed for K40 Laser Acts As an Auto-Focus

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Laser engraving and cutting has something in common with focusing the sun’s rays with a magnifying glass: good focus is critical to results. If materials of varying thicknesses are used, focus needs to be re-set every time the material changes, and manual focusing quickly becomes a chore. [Scorch Works] has a clever solution to avoid constant re-focusing that doesn’t involve sensors or motors of any sort. The result is a self-adjusting bed that compensates for material height changes, ensuring that the top surface of the material is always a fixed distance from the laser’s head.

The way [Scorch Works] has …read more

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Tiny Drone Racing Gates Use Up Those Filament Scraps

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Drone racing comes in different shapes and sizes, and some multirotor racers can be very small indeed. Racing means having gates to fly though, and here’s a clever DIY design by [Qgel] that uses a small 3D printed part and a segment of printer filament as the components for small-scale drone racing gates.

The base is 3D printed as a single piece and is not fussy about tolerances, meanwhile the gate itself is formed from a segment of printer filament. Size is easily adjusted, they disassemble readily, are cheap to produce, and take up very little space. In short, perfect …read more

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Watch The Low-Cost Mechatronics Lab Dispense Candy, Sort Cups

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A lot can be done with simple motors and linear motion when they are mated to the right mechanical design and control systems. Teaching these principles is the goal behind the LCMT (Low Cost Mechatronics Trainer) which is intended primarily as an educational tool. The LCMT takes a “learn by doing” approach to teach a variety of principles by creating a system that takes a cup from a hopper, fills it with candy from a dispenser, then sorts the cups based on color, all done by using the proper combinations of relatively simple systems.

The Low Cost Mechatronics Trainer can …read more

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“Yell to Press B” Mod Makes N64 Controller Worse

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There’s probably no reason anyone would actually desire a mod like this. Well, no good reason. But [William Osman] had been pondering what it would be like to play some classic games with inputs other than buttons, and decided to make an audio sensor responsible for pressing the B button on an old N64 controller. This “Yell To Press B” mod was also something unique to show his hosts when he visited the YouTube video game aficionados, [Game Grumps].

[William] acknowledges that the build is a bit of a hack job, but the project page does a good job of …read more

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Solar-Powered IoT Sensor Saves Wine Batch From Overheating

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Making wine isn’t just about following a recipe, it’s a chemical process that needs to be monitored and managed for best results. The larger the batch, the more painful it is to have something go wrong. This means that the stakes are high for small vineyards such as the family one [Mare] works with, which have insufficient resources to afford high-end equipment yet have the same needs as larger winemakers. The most useful thing to monitor is the temperature profile of the fermentation process, and [Mare] created an exceptional IoT system to do that using LoRa wireless and solar power. …read more

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Set Up A Headless Raspberry Pi, All From Another Computer’s Command Line

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There are differences between setting up a Raspberry Pi and installing an OS on any other computer, but one thing in common is that if you do enough of them, you seek to automate the process any way you can. That is the situation [Peter Lorenzen] found himself in, and his solution is a shell script to install and configure the Raspberry Pi for headless operation, with no need to connect either a keyboard or monitor in the process.

[Peter]’s tool is a script called rpido, and with it the process for setting up a new Raspberry Pi for …read more

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DIY Mini Helical Antennas From Salvaged Co-ax Cable

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[Mare] has a visual guide and simple instructions for making DIY mini helical 868 MHz antennas for LoRa applications. 868 MHz is a license-free band in Europe, and this method yields a perfectly serviceable antenna that’s useful where space is constrained.

The process is simple and well-documented, but as usual with antenna design it requires attention to detail. Wire for the antenna is silver-plated copper, salvaged from the core of RG214U coaxial cable. After straightening, the wire is wound tightly around a 5 mm core. 7 turns are each carefully spaced 2 mm apart. After that, it’s just a matter …read more

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Fail of the Week: Laser-based Persistence of Vision Gadget

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[XTronical]’s idea for a laser-based persistence of vision gadget failed, but the basic idea seemed sound. A row of inexpensive red lasers shine into a spinning mirror and are reflected onto a distant surface, making 8 scan lines. A reflective object sensor detects mirror position, and by rapidly turning individual lasers on and off, a pattern can be drawn out.

That was the idea, anyway. A quick prototype consisting of some small and economical red laser diodes and a double-sided mirror hot glued to the shaft of a small DC motor formed the guts of the unit. [XTronical] worried that …read more

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A Daylight-Readable Bar Graph Display in the 70s Wasn’t Cheap

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LEDs weren’t always an easy solution to displays and indicators. The fine folks at [Industrial Alchemy] shared pictures of a device that shows what kind of effort and cost went into making a high brightness bar graph display in the 70s, back when LEDs were both expensive and not particularly bright. There are no strange materials or methods involved in making the display daylight-readable, but it’s a peek at how solving problems we take for granted today sometimes took a lot of expense and effort.

The display is a row of 28 small incandescent bulbs, mounted in a PCB and …read more

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What Good Are Counterfeit Parts? Believe It Or Not, Maybe A Refund

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[Charles Ouweland] purchased some parts off Aliexpress and noticed that the Texas Instruments logo on some of his parts wasn’t the Texas Instruments logo at all, it was just some kind of abstract shape that vaguely resembled the logo. Suspicious and a little curious, he decided to take a closer look at the MCP1702 3.3v LDO regulators he ordered as well. Testing revealed that they were counterfeits with poor performance.

Looking at the packages, there were some superficial differences in the markings of the counterfeit MCP1702 versus genuine parts from Microchip, but nothing obviously out of place. To conclusively test …read more

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