A set of three linear actuators set atop a green with yellow grid cutting mat. The electric actuator on the top of the image is silver and has a squarish tube. It is slender compared to the other two. A black, hydraulic actuator sits in the middle and is the largest of the three. A silver pneumatic actuator at the bottom of the image is the middle sized unit.

Linear Actuators 101

Linear actuators are a great help when you’re moving something along a single axis, but with so many options, how do you decide? [Jeremy Fielding] walks us through some of the high level tradeoffs of using one type of actuator over another.

There are three main types of linear actuator available to the maker: hydraulic, pneumatic, and electric. Both the hydraulic and pneumatic types move a cylinder with an attached rod through a tube using pressure applied to either side of the cylinder. [Fielding] explains how the pushing force will be greater than the pulling force on these actuators since the rod reduces the available surface area on the cylinder when pulling the rod back into the actuator.

Electric actuators typically use an electric motor to drive a screw that moves the rod in and out. Unsurprisingly, the electric actuator is quieter and more precise than its fluid-driven counterparts. Pneumatic wins out when you want something fast and without a mess if a leak happens. Hydraulics can be driven to higher pressures and are typically best when power is the primary concern which is why we see them in construction equipment.

You can DIY your own linear actuators, we’ve seen tubular stepper motors, and even a linear actuator inspired by muscles.

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Close up of a DIY minimalist EDC multitool, a penny, and a paperclip

This Pocket Multitool Weighs Less Than A Penny

A multitool that weighs less than a penny? Yes, it exists. This video by [ToolTechGeek] shows his titanium flat-cut design tipping the scales at only 1.9 grams—lighter than the 2.5-gram copper penny jingling in your pocket. His reasoning: where most everyday carry (EDC) tools are bulky, overpriced, or simply too much, this hack flips the equation: reduce it to the absolute minimum, yet keep it useful.

You might have seen this before. This second attempt is done by laser-cutting titanium instead of stainless steel. Thinner, tougher, and rust-proof, titanium slashes the weight dramatically, while still keeping edges functional without sharpening. Despite the size, this tool manages to pack in a Phillips and flathead screwdriver, a makeshift saw, a paint-lid opener, a wire bender (yes, tested on a paperclip), and even a 1/4″ wrench doubling as a bit driver. High-torque screwdriving by using the long edges is a clever exploit, and yes—it scrapes wood, snaps zip ties, and even forces a bottle cap open, albeit a bit roughly.

It’s not about replacing your Leatherman; it’s about carrying something instead of nothing. Ultra-minimalist, featherlight, pocket-slip friendly—bet you can’t find a reason not to just have it in your pocket.

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Death Of The Cheque: Australia Moves On

Check (or cheques) have long been a standard way for moving money from one bank account to another. They’re essentially little more than a codified document that puts the necessary information in a standard format to ease processing by all parties involved in a given transaction.

The check was once a routine, if tedious, way for the average person to pay for things like bills, rent, or even groceries. As their relevance continues to wane in the face of newer technology, though, the Australian government is making a plan to phase them out for good.

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How Laser Headlights Died In The US

Automotive headlights started out burning acetylene, before regular electric lightbulbs made them obsolete. In due time, halogen bulbs took over, before the industry began to explore even newer technologies like HID lamps for greater brightness. Laser headlights stood as the next leap forward, promising greater visibility and better light distribution.

Only, the fairytale didn’t last. Just over a decade after laser headlights hit the market, they’re already being abandoned by the manufacturers that brought them to fruition. Laser headlights would end up fighting with one hand behind their back, and ultimately became irrelevant before they ever became the norm.

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Suggested Schematic Standards

We often think that if a piece of software had the level of documentation you usually see for hardware, you wouldn’t think much of it. Sure, there are exceptions. Some hardware is beautifully documented, and poorly documented software is everywhere. [Graham Sutherland’s] been reviewing schematics and put together some notes on what makes a clean schematic.

Like coding standards, some of these are a bit subjective, but we thought it was all good advice. Of course, we’ve also violated some of them when we are in a hurry to get to a simulation.

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2025 One Hertz Challenge: Educational Tool Becomes 10 Stopwatches

Around the globe, some classrooms are using fancy digital handheld devices to let people answer questions. One such example of this hardware is the Smart Response PE. These devices are largely useless outside the classroom, so [Ray Burne] decided to hack one for our 2025 One Hertz Challenge.

The Smart Response PE device is similar in shape and size to an old-school candybar cellphone. It runs on a Texas Instruments CC2533 microcontroller, which drives a simple black-and-white LCD. User interface is via a numeric keypad and a few extra control buttons on the front panel. Thanks to Github user [serisman], there are readily available development tools for this hardware. [Ray] notes it provides a straightforward Arduino-like programming experience.

[Ray] decided to modify the hardware to act as a stopwatch. But not just one stopwatch—ten stopwatches at once! Pressing a number from 0 to 9 will activate that given timer, and it will start ticking up on the LCD screen. One can pause the screen updates to get a temporary laptime reading by pressing the enter key. Meanwhile, pressing the Home button will reset the screen and all timers at once. [Ray] also explains on the project page how to add a real power switch to the device, and how to modify the programming pins for easy access.

It’s a fun build, and one that could prove useful if you regularly find yourself having to time ten of something at once. Maybe eggs? In any case, it’s certainly easier than juggling ten separate stopwatches at once! Meanwhile, if you’re hacking your own obscure hardware finds, don’t hesitate to notify the tipsline!

Digital Etch-A-Sketch Also Plays Snake

The Etch-A-Sketch has been a popular toy for decades. It can be fun to draw on, but you have to get things right the first time, because there’s no undo button. [Tekavou] decided to recreate this popular toy in digital form instead to give it more capabilities. 

The build relies on an Inkplate e-paper screen as a display, which is probably as close you can get in appearance to the aluminium dust and glass screen used in an Etch-a-Sketch. The display is hooked up to an ESP32 microcontroller, which is charged with reading inputs from a pair of rotary encoders. In standard drawing mode, it emulates the behavior of an Etch-A-Sketch, with the ESP32 drawing to the e-paper display as the user turns the encoders to move the cursor. However, it has a magical “undo” feature, where pressing the encoder undoes the last movement, allowing you to craft complex creations without having to get every move perfect on your first attempt. As a fun aside, [Tekavou] also included a fun Snake game. More specifically, it’s inspired by NIBBLES.BAS, a demo program included with Microsoft QBasic back in the day.

We’ve seen all kinds of Etch-A-Sketch builds around these parts, including this impressive roboticized version. Video after the break.

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