⚡ The Analog #116: Air, Angles, and Stadium Design
February 4th, 2025
We’re back with another engineers and founders dinner — this time in Orange County, CA (Costa Mesa) on February 25th. Applications are open with limited seats (~30) – hardware engineers, leaders, founders, and investors are all welcome!
Onshape is offering hardware startups and entrepreneurs free access to Onshape Professional—complete with CAD, rendering, simulation, PDM, and more. Apply for the program to get started today.
Interesting Links 🏭
With the Super Bowl coming up, we stumbled on a video about how the 2025 stadium is designed to maximize profit and it pulled us into a rabbit hole on how modern stadiums are built both structurally and financially to optimize revenue. Two facts we learned from a MIT graduate thesis on the evolution of stadiums:
Stadium Economics: Modern stadiums focus on premium seats because that’s where the money is—80% of revenue comes from 20% of the attendees. Profit comes from three places in ticket sales, non-gate income (advertising, catering, merchandise), and public funding.
Structural Design: Air-supported roofs use a pressurized plastic membrane held aloft by fans, with the internal air pressure providing structural support. This design allows for large, open spans with relatively low construction costs. The structure’s inflation uses a closed feedback loop in a central control system that automatically adjusts air pressure in response to external conditions like wind or snow load.
In seat design for stadiums, the ideal maximum rake, or seating slope, is 34 degrees. Any steeper angles can cause a sense of vertigo as attendees walk downwards. That said, we've sat in the nosebleeds at modern stadiums like Chase Center in SF, and we're pretty sure the rake is well above that—Reddit seems to agree.
A fascinating thread on how the iPhone 6 Bendgate scandal led to the creation of Apple’s internal production lab. At the time in 2014, Apple didn’t control the manufacturing process—they set cost and quality targets while contract manufacturers competed by cutting cycle times. When Apple asked about running 7075 aluminum for the phone frame, vendors quoted cycle times twice as long, driving up costs. The quotes didn’t pass the sniff test, so they pulled the same tools the vendors were using and ran their own tests to prove the cycle times and tool life were the same. Since then, Apple has maintained a dedicated production lab with the sole intent of validating manufacturing methods and supporting design and procurement choices. The lesson: never take a quote at face value.
The author Greg Koenig also wrote one of our favorite pieces of writing: How Apple Makes the Watch.
SemiAnalysis revealed that DeepSeek's total server CapEx is around $1.6B, significantly higher than the $6M often cited for training. The $6M figure only accounts for GPU pre-training expenses, excluding other critical costs like R&D and infrastructure. Despite U.S. export controls, DeepSeek operates with a mix of NVIDIA GPUs, including the China-specific H20s. DeepSeek has introduced innovations like Multi-Head Latent Attention (MLA) which significantly reduce key data (KV cache) memory usage. It is hoped that some of these innovations will be adopted by Western AI labs.
From the SemiAnalysis team: We are confident that their GPU investments account for more than $500M US dollars, even after considering export controls.
“Alf’s Musings” examines the capacitance modelling of Leyden jars, which were the first electrical storage device used as a repetitive charge source for early electrical experiments. The theory extends to explain calculating stray capacitance of any given winding, including top-bottom winding distributions, or toroidal coils. This involves the mutual capacitance matrix which is now a standard output of FEM software.
NASA has demonstrated a low-cost, space safe antenna. Engineers from NASA’s Near Space Network designed and built a 3D-printed antenna, tested it with the network’s relay satellites, and then flew it on a weather balloon. Additive manufacturing should allow NASA to develop mission-specific antennas faster and cheaper than before.
Science Corporation is developing a biohybrid neural interface that uses living neurons cultured on a silicon structure to form natural connections with the brain. The challenge with recording neural activity is proximity—getting close enough to measure signals often means damaging the very tissue you’re trying to study. Sacrificing 10,000 cells to record from 1,000 might be acceptable in cases of severe injury, but that trade-off becomes a major limitation when scaling up. Once implanted, the hybrid neurons grow their own dendrites to interface with multiple neurons per electrode.
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Startup News 🚀
Bonsai Robotics, a startup developing autonomous harvesting robots for agriculture, has secured $15M in Series A funding to address the growing labor shortage in farming. The company designs autonomous tree shakers and sprayers to harvest crops like almonds, pistachios, and walnuts—crops with the highest labor costs according to the USDA. The round was led by Bison Ventures.
Helion, a fusion power startup, has raised $425M in a Series F funding bringing its valuation to $5.245B. The company's latest prototype is designed to be the first fusion reactor to generate electricity, using a unique field-reversed configuration to directly convert fusion energy into power. Helion aims to build the first fusion power plant by 2028 to supply electricity for Microsoft.
Angell, a French e-bike startup, is declaring insolvency after a critical hardware flaw, joining a long list of failed micro-mobility companies. Similar to many startups in the space, the e-bike was manufactured by an OEM with frame tube weldments from external partner SEB facing critical reliability issues.
Alice & Bob, a quantum computing startup, has secured a $104.9M Series B round led by Future French Champions, AVP and Bpifrance to advance their development of fault-tolerant quantum computers. The funds will be used to enhance their cat qubit technology, aiming to build the world's first useful quantum computer by 2030.
Castelion, a defense manufacturer focused on hypersonic weapons, has raised $100M in equity and debt financing to scale manufacturing and conduct capability demonstrations of its first hypersonic strike weapon. The financing includes a $70M Series A round led by Lightspeed Venture Partners and $30M in venture debt from Silicon Valley Bank.
Nobi, a company developing AI-powered smart lights for fall detection in elderly care, has secured $37M in a Series B funding round. The funding, led by Angelini Ventures and Nexus NeuroTech Ventures with participation from Japanese investor 15th Rock, aims to expand Nobi's innovative solutions globally and enhance its platform for improving eldercare.
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Open Jobs 💼
Sponsored:
Shinkei, a seed-stage startup developing fish processing robotics, is hiring in El Segundo, CA
New Grad:
Ambi Robotics is looking for a Mechanical Engineer in Berkeley, CA
Intel is looking for a Silicon Hardware Engineer in Santa Clara, CA
Mid-Level:
Snap is looking for an Opto-Mechanical Engineer in Boulder, CO
Farcast is looking for an Electrical Engineer in San Francisco, CA
Senior to Staff:
OpenAI is hiring for infrastructure roles related to Project Stargate in San Francisco, CA:
Gridware is looking for a Senior Mechanical Engineer & Senior Power Electronics Engineer in San Francisco, CA
Whisker is looking for an Electrical Engineering Manager in Auburn Hills, MI
Internships:
Lumafield is looking for a Mechanical Engineering Intern & Electrical Engineering Intern in Boston, MA
Wing is looking for a Mechatronics Intern in Palo Alto, CA
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