episode 37: past events, lasercutting and fear of breaking the rope

CBA Podcast

You thought that we finally learned from our mistakes and abandoned this podcast, and you thought wrong. Once again it's time to lower your standards, and enjoy a new episode of the CBA Podcast.

We start with some PCB failures and flaws, followed by a very brief review of the Hackalot lasercutter & vinylcutter workshop. We attended T-DOSE, which is a Dutch open source event hosted in Eindhoven.

Then for something slightly out of the ordinary, we talk about back-of-envelope calculations about whether a climbing-rope can actually break if I fall. (Spoiler alert: it cannot.)

Some clarifications and errata about this climbing-rope segment:

To calculate maximum force on the rope, I used the harmonic oscillator formula given here , where the actual force is calculated from fall factor, mass of object, but also the rope's rated impact force. (I forgot to mention that).

Also, I made an error: I mentioned a maximum actual force of approximately 85% the rope's rated impact force, but this is in fact less than 70% - nice.

For those special people who like this: standard EN 892 deals with dynamic ropes like the one discussed, and EN12277 deals with harnesses ("belts"). My harness is tested with a sustained load of 15 kN. The type of carabiner I use is rated for 27 kN load.

Finally, some relevant links:

• Hackalot (Eindhoven, NL) where a lasercutter and vinylcutter live
• T-DOSE Open Source Software event (Eindhoven, NL)
• Wikipedia: fall factor and dynamic rope
• Neoliet indoor sportclimbing (Eindhoven, NL)