Mechanisms: Lead Screws and Ball Screws
Translating rotary motion to linear motion is a basic part of mechatronic design. Take a look at the nearest 3D-printer or CNC router — at least the Cartesian variety — and you’ll see some mechanism that converts the rotation of the the motor shafts into the smooth linear motion needed for each axis.
Hobby-grade machines are as likely as not to use pulleys and timing belts to achieve this translation, and that generally meets the needs of the machine. But in some machines, the stretchiness of a belt won’t cut it, and the designer may turn to some variety of …read more
Alice Evans: Brucellosis, or Why We Pasteurize Milk
It’s easy to forget how much illness and death was caused by our food and drink just one hundred years ago. Our modern food systems, backed by sound research and decent regulation, have elevated food safety to the point where outbreaks of illness are big news. If you get sick from a burger, or a nice tall glass of milk, it’s no longer a mystery what happened. Instead we ask why, and “who screwed up?”
In the early 20th century though, many food-borne illnesses were still a mystery, and microbiology was a scientific endeavor that was just getting started. Alice …read more
Hello, And Please Don’t Hang Up: The Scourge of Robocalls
Over the last few months, I’ve noticed extra calls coming in from local numbers, and if you live in the US, I suspect maybe you have too. These calls are either just dead air, or recordings that start with “Please don’t hang up.” Out of curiosity, I’ve called back on the number the call claims to be from. Each time, the message is that this number has been disconnected and is no longer in service. This sounds like the plot of a budget horror movie, how am I being called from a disconnected number? Rather than a phantom in the …read more
Soyuz Failure Leaves Questions Unanswered
The Russian space program experienced its first serious incident on a manned mission in 35 years when Soyuz MS-10 failed during ascent on October 11th, 2018. The abort system worked as designed, and crew members Aleksey Ovchinin and Nick Hague landed safely approximately 430 km from the launch site in Baikonur. Beyond being put through unusually high G forces, the two men suffered no injuries and will have their mission recycled for a future flight.
From an abort standpoint, the event went as well as could possibly be expected. The fact that the crew walked away unharmed is a testament …read more
The Dual In-Line Package and How It Got That Way
For most of human history, our inventions and innovations have been at a scale that’s literally easy to grasp. From the largest cathedral to the finest pocket watch, everything that went into our constructions has been something we could see with our own eyes and manipulate with our hands. But in the middle of the 20th century, we started making really, really small stuff: semiconductors. For the first time, we were able to create mechanisms too small to be seen with the naked eye, and too fine to handle with our comparatively huge hands. We needed a way to scale …read more