May 22, 2025

#694 – Voltage, Vibes, and VOCs

1 hour 11 minutes

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This episode was recorded Monday the 12th, which has implications on discussions.

Dave recently returned from Melbourne for Dave’s recent visit to Electronex.

Dave saw past guest Scott Williams there (he has been interviewed by both Dave and Chris). Scott’s company Xentronics is also a Golioth partner

They discussed service providers in the electronics industry at including turnkey solutions (concept to production and marketing) versus services only (firmware, PCB layout, CAD).

The choice of show for a service provider might depend on the customer vertical (e.g., medical expo for medical device design).

Farmers are described as rough clients due to being cost-constrained, needing durable solutions for harsh environments, and being unforgiving of downtime.

The Australian Manufacturing Week was unexpectedly enormous, dwarfing the electronics show in scale and attendance, with lines up to 40 minutes long just to get in.

The manufacturing show featured “Heavy Metal” manufacturing, like laser cutters, sheet metal benders, and giant machines cutting thick steel, which Dave found more exciting than the electronics demos.

They discussed the scale of manufacturing equipment, comparing it to shows like IMTS in Chicago with multi-story machining centers and machines weighing hundreds of tons.

Australia manufactures things like steel, large steel structures (bridges), and large custom parts like excavator scoops.

Dave is conducting environmental air quality tests in his office, measuring formaldehyde, CO2, and other factors. He has to run his air conditioning for one of the test conditions.

The environmental monitor measures temperature, pressure, humidity, VOCs, noise, carbon dioxide, formaldehyde, PM2.5 particulate matter, and radiation. The radiation sensor uses a tube requiring 381 volts.

XKCD graphic showing relative radiation

Dave observes large formaldehyde spikes every time he opens his door, which go down within about 10 minutes. His CO2 levels are typically 800-900 ppm.

The AC unit cycling is visible in the humidity measurements.

Chris asks about the availability of affordable VOC sensors now. Dave believes his monitor uses a common sensor like the BME680.

Chris explains that the availability of affordable VOC sensors is linked to FEMA trailers after Hurricane Katrina, where high formaldehyde levels caused illness, leading to regulations and subsequently more affordable sensors. Modern VOC sensors often measure gas resistivity in ohms.

Some PM2.5 sensors use a fan and a laser to detect particles.

Dave saw small desktop lathes at the manufacturing show and was tempted to buy one for $800.

Chris explains the difference between a mill and a lathe. Potential uses for a lathe are discussed, including making knobs.

Chris advises against buying a personal machining tool like a lathe or mill unless you need parts immediately, suggesting using online services instead, as getting $800 of value from occasional use is difficult.

Dave jokingly suggests a lathe might be useful for “zombie apocalypse manufacturing”, or more darkly, for making gun barrels.

Chris mentions his past experience with a mill, which he traded for a 3D printer kit. He now prefers “it just works” solutions.

They discuss receiving free 3D resin printers and the difficulty of finding uses for them unless you are already skilled in 3D modeling.

Discussion shifts to the recent drop in tariffs between China and the US. Dave believes this will lead to lots of manufacturing coming back to the US, citing announcements from car companies and others (but providing no sources). Chris found this CBS article after the fact, but it’s light on details.

NPR covered how tariffs are impacting Digikey and Thief River Falls

Chris is skeptical that the tariff drops or initiatives like the CHIPS Act will cause significant, long-term shifts in the global supply chain, especially for components like capacitors or packaged semiconductors.

The complexities of building fabs and the long lead times are mentioned in relation to the CHIPS Act.

Chris recommends a YouTube channel about shipping and logistics and mentions MarineTraffic.com for tracking live global shipping data.

Dave mentions issues with Bluetooth data dropouts and incorrect values on a new Brymen BM787 multimeter.

Dave recently made a video about Test Controller, a free Java-based program that automates hundreds of test instruments (multimeters, power supplies, loads) via serial interfaces. It allows scripting and custom driver creation.

Dave considers using Test Controller and multiple instruments with his microscope PC for overlaying data on video.

Chris introduces the concept of “vibe coding,” which means letting AI do the coding. You act as a product manager providing requirements and feedback.

Dave has used AI for coding before and is interested in using it for his next project due to infrequent coding leading to needing to relearn tools. He suggests using it for a simple timer project, especially for annoying tasks like generating fonts.

Chris is using AI for a location-sharing web app prototype for a meetup. He describes the experience of watching the AI modify files and interact with tools as “trippy”. He uses “Claude credits” for this.

They discuss AI as a new tool. Chris expresses concern about how students learning to code today will develop troubleshooting skills if AI does much of the basic work.

Dave received a new piece of high-end test equipment: a Microtest Impedance Analyzer (model 6632). This is distinct from an LCR meter and can measure the entire frequency impedance sweep up to 10 MHz (for the model received).

The impedance analyzer can be used to characterize components like PCB inductors, assess bypass capacitor performance on boards, or measure materials like piezoelectric substrates. It can also show admittance circles and DC bias characteristics.

Chris mentioned that past guest Carl Bugeja would benefit from a tool like the impedance analyzer

Dave notes the impedance analyzer is very specific and requires special fixturing. It supports open, short, and load compensation.

Dave also recently received a heavy GW Instek AC power source, which can be used for power line simulation (adding spikes, dropouts, etc.) to test products.

Trying out generating show notes using NotebookLM from Google. We’d love your feedback in the comments.

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By The Amp Hour (Chris Gammell and David L Jones)

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