Author: John Elliot V

174 Articles

A photo of a fully assembled PVCSub.

PVCSub: A Submarine From The Plumbing Aisle

July 18, 2025 by 11 Comments

Today in the submersibles department our hacker [Rupin Chheda] wrote in to tell us about their submarine project.

This sub is made from a few lengths of PVC piping of various diameters. There is an inflation system comprised of a solenoid and a pump, and a deflation system, also comprised of a solenoid and a pump. The inflation and deflation systems are used to flood or evacuate the ballast which controls depth. There are three pumps for propulsion and steering, one central pump for propulsion and two side pumps for directional control, allowing for steering through differential thrust. Power and control is external and provided via CAT6 cable.

Continue reading “PVCSub: A Submarine From The Plumbing Aisle” →

Screenshot of the cheatsheet being developed in Inkscape

Improve Your KiCad Productivity With These Considered Shortcut Keys

July 17, 2025 by 15 Comments

[Pat Deegan] from Psychogenic Technologies shows us two KiCad tips to save a million clicks, and he made a video to support it, embedded below.

In the same way that it makes sense for you to learn to touch type if you’re going to be using a computer a lot, it makes sense for you to put some thought and effort into your KiCad keyboard shortcuts keys, too.

In this video [Pat] introduces the keymap that he has come up with for the KiCad programs (schematic capture and PCB layout) and explains the rules of thumb that he used to generate his recommended shortcut keys, being:

  • one handed operation; you should try to make sure that you can operate the keyboard with one hand so your other hand can stay on your mouse
  • proximity follows frequency; if you use it a lot it should be close to hand
  • same purpose, same place; across programs similar functions should share the same key
  • birds of a feather flock together; similar and related functionality kept in proximate clusters
  • typing trounces topography; if you have to use both hands for typing you have to take your hand off the mouse anyway so then it doesn’t really matter where on the keyboard the shortcut key is

You can find importable KiCad keymaps and customizable SVG cheatsheets in the downloads section.

[Pat]’s video includes some other tips and commentary, but for us the big takeaway was the keymaps. He’s also got a course that you can follow along with for free. And if you haven’t been keeping abreast of developments, KiCad is now at version 9, as of February this year.

Continue reading “Improve Your KiCad Productivity With These Considered Shortcut Keys” →

A photo of a Stirling Engine attached to a bike

Building A Stirling Engine Bike

July 17, 2025 by 27 Comments

Over on his YouTube channel [Tom Stanton] shows us how to build a Stirling Engine for a bike.

A Stirling Engine is a heat engine, powered by the expansion and contraction of a working fluid (such as air) which is heated and cooled in a cycle. In the video [Tom] begins by demonstrating the Stirling Engine with some model engines and explains the role of the displacer piston. His target power output for his bike engine is 150 watts (about 0.2 horsepower) which is enough power to cycle at about 15 mph (about 24 km/h). After considering a CPU heatsink as the cooling system he decided on water cooling instead.

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An old PC with CRT monitor

ProtoWeb: Browsing The Information Superhighway Like It’s 1995

July 17, 2025 by 19 Comments

Feeling nostalgic? Weren’t around in the 90s but wonder what it was like? ProtoWeb has you covered! Over on his YouTube channel [RetroTech Chris] shows you how to browse the web like it’s 1995.

The service that [RetroTech Chris] introduces is on the web over here: protoweb.org. The way it works is that you configure your browser to use the service’s proxy server, then the service will be able to intercept your browsing activity and serve you old content from its cache. Also, for some supported sites, you will see present-day content but presented in the format you would have seen in the 90s. Once you have configured your browser to use the ProtoWeb proxy you can navigate to http://www.inode.com/ where you will find a directory listing of sites which have been archived or emulated within the service.

In his video [RetroTech Chris] actually demos some of the old web browsers running on old hardware, which is a very good recreation of what things were like. If you want the most realistic experience you can even configure ProtoWeb to slow down your network connection to the speed of a 56k dial-up modem. There are some things from the 90s that we miss, but waiting for websites to load isn’t one of them!

We had a look in our own archive to see how far back we here at Hackaday could go, and we found our first post, from September 2004: Radioshack Phone Dialer – Red Box. A red box! Spicy.

Continue reading “ProtoWeb: Browsing The Information Superhighway Like It’s 1995” →

Front panel of Sony Blu-ray player

Blu-ray Won, But At What Cost?

July 16, 2025 by 73 Comments

Over on their substack [ObsoleteSony] has a new article: The Last Disc: How Blu-ray Won the War but Lost the Future.

In this article the author takes us through the history of Blu-ray media and how under Sony’s stewardship it successfully defeated the competing format of the time, HD DVD. Sony started behind the eight ball but through some deft maneuvering managed to come out on top. Perhaps the most significant contributing factor was the inclusion of Blu-ray drives in the PlayStation 3.

The person leading the Blu-ray initiative for Sony was Masanobu Yamamoto, whose legacy was the compact disc. What was needed was a personal media format which could deliver for high-definition 1080p video. As the DVD format did not have the storage capacity required, new formats needed to be developed. The enabling technology for both Blu-ray and HD DVD media was the blue laser as it allowed for more compact encoding.

Sony’s Blu-ray format became the dominating format for high-definition personal media…just as physical media died.

Thanks to [Stephen Walters] for writing in about this one.

A hand holding the foxhunt transmitter

2025 One Hertz Challenge: Ham Radio Foxhunt Transmitter

July 13, 2025 by 9 Comments

[Jim Matthews] submitted his Ham Radio foxhunt transmitter project for the 2025 One Hertz Challenge.

This is a clever Spartan build. In order to create a radio beacon for use in a “fox hunt” [Jim] combined a SR-T300 walkie talkie module with a phototransistor and oscillating LED circuit. The phototransistor and oscillating LED are secured face-to-face inside heat shrink tubing which isolates them from ambient light. When the LED flashes on the phototransistor powers the radio which transmits a tone in the UHF band.

A fox hunt is a game played by radio enthusiasts in which players use radio signals to triangulate and find a hidden beacon. [Jim]’s circuit is the beacon, and when it’s powered by a three volt CR2032 battery, it transmits a strong signal over several hundred yards at 433.5 MHz, within the amateur radio UHF band.

If you’re interested in radio beacons you might like to read about the WSPR beacon.

2025 Hackaday One Hertz Challenge
Picture of front and back of thumb drive enclosure

Jcorp Nomad: ESP32-S3 Offline Media Server In A Thumbdrive

July 13, 2025 by 27 Comments

[Jackson Studner] wrote in to let us know about his ESP32-based media server: Jcorp Nomad.

This project uses a ESP32-S3 to create a WiFi hotspot you can connect to from your devices. The hotspot is a captive portal which directs the user to a web-interface comprised of static HTML assets which are in situ with the various media on an attached SD card formatted with a FAT32 file system. The static HTML assets are generated by the media.py Python 3 script when the ESP32 boots.

This project exists because the typical Raspberry Pi media server costs more than an ESP32 does. The ESP32 is smaller too, and demands less power.

According to [Jackson] this ESP32-based solution can support at least four concurrent viewers. The captive portal is implemented with DNS and HTTP services from the ESP32. The firmware is an Arduino project that integrates a bunch of libraries to provide the necessary services. The Jcorp Nomad media template supports Books (in pdf files), Music (in mp3 files), and Movies and Shows (in mp4 files). Also there is a convention for including JPEG files which can represent media in the user-interface.

And the icing on the cake? The project files include STL files so you can 3D print an enclosure. All in all, a very nice hack.