Many people have looked Death in the eye sockets and survived to tell others about it, but few situations speak as much to the imagination as situations where there’s absolutely zero prospect of rescuers swooping in. Top among these is the harrowing tale of the Apollo 13 moon mission and its crew – commanded by James “Jim” Lovell – as they found themselves stranded in space far away from Earth in a crippled spacecraft, facing near-certain doom.
Lovell and his crew came away from that experience in one piece, with millions tuning into the live broadcast on April 17 of 1970 as the capsule managed to land safely back on Earth, defying all odds. Like so many NASA astronauts, Lovell was a test pilot. He graduated from the US Naval Academy in Maryland, serving in the US Navy as a mechanical engineer, flight instructor and more, before being selected as NASA astronaut.
On August 7, 2025, Lovell died at the age of 97 at his home in Illinois, after a dizzying career that saw a Moon walk swapped for an in-space rescue mission like never seen before.
The largest European hacker camp this year was in the Netherlands — What Hackers Yearn (WHY) 2025 is the latest in the long-running series of four-yearly events from that country, and 2025 saw a move from the Flevoland site used by SHA2017 and MCH2021, back to just north of Alkmaar in Noord-Holland, where the OHM2013 event took place. WHY has found itself making the news in the Dutch technical media for all the wrong reasons over the last few days, after serious concerns were raised about the fire safety of its badge.
This is the cell supplied with the WHY badge, complete with manufacturer’s warning.
The concerns were raised from the RevSpace hackerspace in Leidschendam, and centre around the design of the battery power traces on the PCB between the battery holders and the power supply circuitry. Because the 18650 cells supplied with that badge lack any protection circuitry, bridging the power traces could be a fire risk.
In short: their report names the cell holders as having tags too large for their pads on the PCB, a too-tight gap between positive and negative battery traces, protected only by soldermask, and the inadequacy of the badge’s short circuit protection. In the event that metal shorted these battery tags, or wore through the soldermask, the batteries would be effectively shorted, and traces or components could get dangerously hot.
The WHY organizers have responded with a printed disclaimer leaflet warning against misuse of the cells, and added a last-minute epoxy coating to the boards to offer additional protection. Some people are 3D-printing cases, which should also help reduce the risk of short-circuiting due to foreign metal objects. Using an external powerbank with short-circuit protection instead of the cells would solve the problem as well. Meanwhile a group of hackers collecting aid for Ukraine are accepting the batteries as donations.
It’s understood that sometimes bugs find their way into any project, and in that an event badge is no exception. In this particular case, the original Dutch badge team resigned en masse at the start of the year following a disagreement with the WHY2025 organizers, so this badge has been a particularly hurried production. Either way, we are fortunate that the issue was spotted, and conference organizers took action before any regrettable incidents occurred.
At first glance, [RobBest]’s constant current source looks old school. The box is somewhat old-fashioned, featuring switches and binding posts. Most importantly, there’s a large analog meter dominating the front panel. Then you notice the OLED display, and you know something’s up.
The device can source or sink a constant current. In addition, it features a timer that calculates milliamp-hours and automatically turns off when not in use. The brain is a PIC 16F1765, which controls the screen, the buttons, and a few relays. While that might seem an odd choice for the processor, it is actually smart. The device has both a DAC and an ADC, plus an internal op amp. The analog output and a single pass transistor control the current flow, while the two relays flip it between a source and a sink.
Without that op amp, the DAC can’t produce much current. However, by passing it through the onboard amplifier, the output can drive about 100 mA, which is sufficient for this project.
This is a classic circuit, but the addition of a CPU and a display gives it capabilities that would have been very difficult to build back in the day. Want to dive into the theory behind constant current sources? Or just the practical use of a voltage regulator to make one?
