2022-03-28

Notes, 2022-03-28.

For the past six months, I’ve been working on the detailed design of a new hardware product. There are a seemingly endless number of decisions to be made, and I’m reminded of the iron triangle of project management—that projects are triple constrained by quality, cost, and time. My biggest enemy right now is time. With enough time, I know I could create a higher quality product at a lower cost, and that’s what makes finalizing it for production bittersweet.

A more nuanced way to evaluate designs would probably be a radar chart, with each axis representing a performance metric and the design goal being to maximize area filled in. But even so, the realist in me knows that there would be tradeoffs. There’s the design engineer in me who wants the product to look good. The manufacturing engineer in me who knows that certain features incur expensive custom tooling. The sustaining engineer in me who knows that my product will have to be supported for years to come. Without those perspectives adding axes to the chart and pulling in their respective directions, the end result would be fragmented.

Whatever you are working on, there are always going to be tradeoffs–but I hope you optimize it with a passion.

-Sean Kelley

The most clicked link from last week's issue (~7% of opens) was a real-time map of energy production & distribution data in 150 countries. In the Members' weekly lunchtime Zoom chat, we're talking about automatic bike suspension systems, anechoic chambers, and the Swedish national waffle day.

Planning & Strategy.

• Label printers have long avoided the authentic ink enforcement of standard paper printers, because they use heat instead of ink. But now Dymo has now figured out how to embed RFID chips into the label rolls themselves. While marketed as a way to know what label type is loaded and how many labels are left, it will be used to lock customers into buying their higher priced labels. I own an older (non-DRM’d) Dymo printer and use cheaper non-Dymo labels – without issue.
• The Brooklyn Nets debuted the first virtual reality broadcast of a basketball game using volumetric data, which was streamed from over 100 cameras within Barclays Center. While I see value in being able to watch a replay from different angles, there’s something unsettling about choosing to watch a whole game in virtual reality.

Making & Manufacturing.

• With lower costs and readily available materials, shipping container houses are a rapidly growing market. Contrary to all of the container home designs I’ve seen, this article suggests that the best way to insulate a shipping container home is from the outside. This keeps the steel from corroding and leaves more space for living on the inside. The downside is that no one will be able to tell you recycled a shipping container, which is part of the allure. Here are some beautiful examples of shipping container architecture, many of which show their exterior proudly.
• How to read DC motor performance curves to choose the best motor for your application.

Maintenance, Repair & Operations.

• An overview of the soon-to-be-completed £18 billion Crossrail project, which will allow 1.5 million more people to commute to central London within 45 minutes. The 42 km (26 miles) of tunnel were completed in 2015 with the help of 8 separate tunnel boring machines, marvels of engineering themselves. While cost overruns and delays are common in infrastructure projects of this scale, a bigger question now is whether the investment will pay off given shifting commute patterns since COVID. Regardless, I look forward to riding it one day.
• Python’s motto is “batteries included,” coming with a comprehensive standard library. Python is considering the removal of “dead batteries” within its code – technical debt that has accumulated over time and is no longer actively maintained. However, they are finding that even outdated modules still have supporters and dependencies that make removal difficult.

Distribution & Logistics.

• Staxxon makes folding shipping containers that can shrink 5 empty containers into the size of one. This short video, from 2011, shows an initial prototype being folded. Staxxon isn’t the only company to have had this idea; a quick search returns several competitors. Nevertheless, it strikes me that if ever there was a time for this idea to succeed it is now, as empty containers pile up in ports at record levels. Currently, 40% of the containers in the Port of Los Angeles are sitting empty, a 5% increase over last year.
  
  Once a rigid design adds multiple joints that are exposed to the elements and transport damage, I would expect significantly higher maintenance costs and shorter useful life. Staxxon’s cost savings calculator abstracts this to a 1.5x multiple in maintenance cost. Since their containers are still in preorder, we will have to wait for data to confirm.
• Raspberry Pi is selling its RP2040 microcontroller chips for discount in bulk. Meanwhile their flagship computer, the Raspberry Pi 4, is sold out via their approved resellers and selling for 4x the sticker price elsewhere. This highlights that the chip shortage can be quite product specific: one core component might be readily available, but another part is out of stock and as a result an entire assembly is off the shelf for months. As someone who has dealt with microcontroller shortages in the past year, having assurances of chip availability is critical. As a result, I expect the RP2040 to appear in more embedded projects moving forward.

Inspection, Testing & Analysis.

• As the Industrial Revolution brought down the cost of cast iron, it began to be used for columns in buildings. But as I can attest to from my own experience working with large castings, it can be challenging to get rid of voids and material inconsistencies in cast parts, making them useful as columns in compression, but less effective as beams in tension. These downsides and subsequent failures of some cast iron structures led to their eventual replacement by increasingly cheap and uniform steel. By the 1900s, steel was the dominant structural material between the two and by the 1930s cast iron columns had been completely phased out. Here are examples of cast iron architecture still around today, often identifiable by their regal, patterned facades.
• Researchers at MIT have taught a four legged robot how to learn to run. They did this by rewarding the control system whenever it moves fast. While this process of trial and error would normally take a very long time, they ran it in a sped up simulation so that the learning took place in 3 hours instead of 100 days. The result is a robot that can move much faster than a typical march and adapt to more complex terrain. Their project page shows similar projects in this field that the PI calls “computational sensorimotor learning” or simply giving robots “common sense.”

Tangents.

• A thorough thread in The Prepared’s Member’s Slack had us pursuing the optimal way to peel hard boiled eggs at home. Here’s how a hard boiled egg factory does it.

The cast iron structure of the U.S. Capitol dome.