tomkinstinch
Joined 18 years ago
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Member since
Dec 31
Recent submissions
Comment · 2 years ago
Looking forward to the day when FreeCAD is a viable and stable option for free parametric CAD. There are a few free options for direct modeling, but not for parametric design.
As far as commercial software goes, my current favorite CAD software for hobby use is Rhino[1]. It's not parametric[2], but it's stable, fast[3], can import and export a wide variety of 3D file types, and it's pay-once-per-major-release. It's not cloud-based. The marketing around it seems to emphasize design/architecture/artistic use cases, but it also works well for dimensionally-accurate mechanical parts.
For those eligible for a student license, the pricing is reasonable (cheaper still if you shop around among third-party edu software vendors). Surprisingly, the student license also allows commercial use.
2. Well, Rhino is not parametric in the usual sketch-based way. People do wild things with the Grasshopper plugin.
3. Rhino also runs on macOS, w/ hardware acceleration of graphics via Metal
Comment · 2 years ago
I Contain Multitudes, by Ed Yong
Comment · 2 years ago
For anyone with a UDMP looking to disable remote access via UniFi servers, the setting isn't under the Network application, it's part of the higher level console management:
Console Settings (menu on left) -> Advanced (heading) -> "Remote Access (checkbox)"
Or via: https://$UDMP_IP/console-settings
(Hopefully the setting applies locally...)
Comment · 3 years ago
Depending on the wavelength, Spectralon (sintered PTFE powder) is a bit better. At least until it gets dirty.
Comment · 5 years ago
I wonder if a pump like this could be made smaller using a perfluorocarbon liquid like FC-70 (Perfluorotripentylamine)—nearly double the density of water, higher boiling point, non-flammable, and would not impart water vapor to the compressed air.
Comment · 6 years ago
The Apple Store sells both and will let you compare the two models if you ask nicely (with new/clean AirPods). I found AirPods have noticeably better noise cancellation (for me) than the QC35s, but YMMV. Subtle but better. It's hard to say if my impression was due to better passive noise isolation or improved active noise cancellation (does the QC35 have an error-correction microphone downstream?). One thing that is absolutely true is that the QC35s do not work as well mechanically for those of us who wear eyeglasses: the cushions can't seal around the temple pieces of the frames, so some sound will always leak under the eyeglasses. For that reason alone—even if the AirPods have equivalent noise cancellation tech—the AirPods can work better for people with glasses as long as the tips seal properly. My wife, an eyeglass wearer with long hair, also found the AirPods more effective at reducing noise when we tried them both at the Apple Store. I certainly find them effective for commuter rail travel.
As an aside, one slightly annoying usability issue with the AirPods is that in comparison to the QC35 they behave differently when part of a multi-output audio device under MacOS. My wife and I often watch video using two pairs of bluetooth headphones paired and synced to the same Macbook Pro[1,2]. It's great for late-night movies in city apartments. Using the QC35s and her headphones, the aggregate device remains selected when the QC35s are paused or turned off (meaning, she can still listen if I go out of range or turn off my headphones). With the AirPods, if I take one out of my ear (to scratch an itch, say), the AirPods suddenly become the only audio output device when I put it back in, and the second pair of headphones goes silent. A small annoyance, but curious.
1. Set up your own bluetooth audio "splitter" to allow multiple people to listen togther: https://support.apple.com/guide/audio-midi-setup/play-audio-...
Comment · 7 years ago
Indeed; a good library is a long-tail institution. The Harvard Library system has a large collection of books at the various on-campus libraries, but an immense catalog of infrequently accessed books at a "depository" warehouse off-site. Scholars can request items from the Depository and receive them within a day.
This split-storage model may a sensible solution for other universities going forward: prime and expensive library buildings on-campus can be reserved for quiet study areas and a few commonly-used books, with the main collection of books retrievable from a nearby location where land is less expensive. It also has the advantage of allowing books to be stored in the ideal climate for their preservation.
Fun fact about the Harvard Depository: books are organized not by topic, publication date, or anything resembling the Dewey decimal system, but rather by a metric that makes sense for high-density: physical size. Books are stored in barcoded boxes by height. Here is an artsy documentary, "Cold Storage," about the Depository:
or in interactive form:
Comment · 7 years ago
The coolest solution I've read about to note the producer is to emboss a hologram in the metal, though perhaps with enough care this too could be faked or copied:
Comment · 7 years ago
Helpful tip, thanks. Here's the Safety Data Sheet (SDS) in case anyone is curious what's in 3M 38983 General Purpose Adhesive Remover[1]: Mostly methyl acetate, with some naptha, xylene, and a small amount of ethylbenzene. Definitely worth heeding the precautionary statements...
For contrast, "Goo Gone" is mostly naptha-like light petroleum distillate with small fractions of limonene and orange extract[2].
1. https://multimedia.3m.com/mws/mediawebserver?mwsId=SSSSSuUn_...
2. https://googone.com/mr_sds/data/2018-06-14%2013:44:51/GG_Ori...
Comment · 7 years ago
Hot water "hydronic" heating with radiators is very common in the US as well, at least among homes in the Northeastern US constructed before the 1960s. It's a shame more new construction does not use hot water heating in conjunction with central air for cooling because radiators are much quieter, more efficient, and better for those with asthma.
Chris Tomkins-Tinch, Ph.D.
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I do bioinformatics, full stack dev, instrument electronics/embedded systems/firmware, simple optics, CAD/CAM/rapid prototyping, some wet bench biotech, and technical photography.
open to interesting projects