You can go retro by using an old video game console or a PC from the 1980s, but why stop there when, like one man, you can build your own vacuum tube computer using 75-year-old recycled components? A UK resident who identifies himself only as “Mike” has done just that, as detailed on his tube computer website and accompanying Hackaday project page. Mike’s tube computer is primarily made up of 460 recycled, Soviet-era 6N3P vacuum tubes, which were common enough in their age to be readily and cheaply available online. “Many were used and then stored for over 50 years, so life expectancy may be questionable,” Mike explained on Hackaday. A new 6N3P tube is supposed to have around 500 hours of life, but because each has been used, its current condition is essentially a mystery. Throw in manufacturing inconsistencies of mid-century Soviet Russia, and each tube had enough variability to necessitate extensive testing, Mike explains in the technical writeup on his website. “I calculated the component values and tested the results, but in many cases the theory did not accurately match the practice,” Mike writes. “So I built a test rig to test the viability of various component values and found a range of values that seemed to work in most cases.” All told, Mike’s tube computer, with its 460 6N3P tubes, consists of 920 thermionic triodes that use heat to release electrons for his computing work. Those tubes are mounted to 46 separate 10-tube PCBs, which in turn sit on five backplane PCBs. The entire thing includes a control console that Mike describes as “far too simple” and in need of a complete redesign to better handle variations in the computer’s logic levels. It takes between 10 and 15 minutes for the entire system to stabilize once switched on, Mike said, resulting in a “warm and cozy computer room.” The tubes all power up in random states, requiring the machine to be reset each time it is switched on, but then it’s ready for the fun part: computing. The entire thing uses NOR (i.e., not OR) gates, just like the Apollo guidance computers that got humans to the Moon, which allows it to be a bit smaller than some of the other classic tube computers of yesteryear. As for what it can do, well - 16-bit math is a possibility, as well as anything else that can be done with a limited set of 16 instructions on a 4-bit instruction register. Mike has it configured to output a 64-bit Fibonacci sequence and, more excitingly for his grandchildren and the kid in all of us, plans to use it to power a simple flight simulator once its I/O system is finished. “The basic idea is that back in the 1920s the commercial development of the British R80 airship had actually been approved by the government and the Airship is moored overnight at the wonderful Brighton Aerodrome before a morning launch on a voyage to Paris,” Mike says on his website. “By pressing controls on the image of the bridge of the R80 you can direct the airship software,” he adds. “You can control the ballast, gas release, engine power, elevators, rudder and the bow mooring gear, which is used to release the airship from the tower.” He says that “a bit of vision” is needed to picture oneself flying an airship from Brighton to Paris, as the machine has no graphical output aside from a single mechanical display that used to serve as a clock at a British Rail station. The tube computer’s binary output is used to directly control the mechanical display. Mike describes his fascination with tube computers as “an addiction,” noting that this is the third such system he’s built since getting his first one up and running in 2021. “I designed The Tube Computer so it could show itself working at the most fundamental level of computing,” Mike says, while noting that he’s always careful to keep a fire extinguisher handy thanks to the fact you can smell it running due to all the heat it generates - enough to keep its entire room warm. “The Tube Computer has behaved itself so far, unlike a previous system that went BANG twice,” Mike said, adding that it still requires regular adjustments which, due to its size and position hanging on a wall, require a ladder to undertake. “It is probably one of the few computers that needs both a small tweeker [sic] and a big step ladder.” ®

Tesla's Cybercab's wheels have only just hit the asphalt for its commercial launch and the autonomous vehicle has already attracted the attention of the US National Highway Traffic Safety Administration (NHTSA). The body announced an investigation into Tesla's self-certification of the vehicle at the weekend. Central to the probe is the fact that the Cybercab famously lacks conventional controls. The NHTSA says there are "clear vehicle performance requirements" – stuff like brake controls – that "in order for automakers to access the US market, they must certify that their vehicles meet these standards – subject to oversight from the agency to confirm compliance. When certified vehicles appear to not adhere to these requirements, NHTSA conducts an investigation." The NHTSA is updating the requirements for autonomous vehicles designed never to be operated by a human, but Tesla appears to have jumped the gun somewhat, prompting the agency to open an Audit Query (AQ) just hours after the Cybercab began a commercial rollout on the streets of Austin, Texas. Tesla told the NHTSA that it had certified the Cybercab "as compliant with all applicable Federal Motor Vehicle Safety Standards (FMVSS)." The vehicles lack permanently attached manual controls such as a brake pedal, accelerator, steering wheel, or mirrors. In the AQ, the agency wrote it intended to "examine the process and technical data on which Tesla relied when certifying the Cybercab and related issues. "Among other things, NHTSA will consider the extent to which Tesla’s certification depended on determinations that certain FMVSS are inapplicable to the Cybercab." Tesla is not the only company with autonomous vehicles ferrying passengers around on US roads without using conventional controls in the cabin. Amazon tentacle Zoox, for example, was granted a two-year exemption [PDF] at the end of July 2026, with the proviso that "not more than 2,500 exempted vehicles are introduced into interstate commerce for commercial deployment in any 12-month period." There is therefore precedent. However, the NHTSA wants to see how Tesla came up with its self-certification for the Cybercab. NHTSA Administrator Jonathan Morrison said, "NHTSA fully supports the safe development and deployment of automated vehicles. But as the federal regulator, we need to ensure that all of our laws are followed." The agency noted, "When certified vehicles appear to not adhere to these requirements, NHTSA conducts an investigation." ®

Victorian buyers previewed distant mansions through lenses and creativity