Torturing An Instrumented Dive Watch, For Science

The Internet is a wild and wooly place where people can spout off about anything with impunity. If you sound like you know what you’re talking about and throw around a few bits of the appropriate jargon, chances are good that somebody out there will believe whatever you’re selling.

Case in point: those that purport that watches rated for 300-meter dives will leak if you wiggle them around too much in the shower. Seems preposterous, but rather than just dismiss the claim, [Kristopher Marciniak] chose to disprove it with a tiny wireless pressure sensor stuffed into a dive watch case. The idea occurred to him when his gaze fell across an ESP-01 module next to a watch on his bench. Figuring the two needed to get together, he ordered a BMP280 pressure sensor board, tiny enough itself to fit anywhere. Teamed up with a small LiPo pack, everything was stuffed into an Invicta dive watch case. A little code was added to log the temperature and pressure and transmit the results over WiFi, and [Kristopher] was off to torture test his setup.

The first interesting result is how exquisitely sensitive the sensor is, and how much a small change in temperature can affect the pressure inside the case. The watch took a simulated dive to 70 meters in a pressure vessel, which only increased the internal pressure marginally, and took a skin-flaying shower with a 2300-PSI (16 MPa) pressure washer, also with minimal impact. The video below shows the results, but the take-home message is that a dive watch that leaks in the shower isn’t much of a dive watch.

Hats off to [Kristopher] for doing the work here. We always love citizen science efforts such as this, whether it’s hardware-free radio astronomy or sampling whale snot with a drone.

Continue reading “Torturing An Instrumented Dive Watch, For Science”

Making A Bathymetric Book By Hand And Searching For An Easier Way

We first saw this Bathymetric Book at our local hackerspace, Sector67, quite some time ago. [Caroline Rose] gave a seven minute presentation on the project as part of the monthly meeting which is open to the public. You can get a pretty good feel for the book that includes a to-scale depth representation of Crater Lake in the introductory post which she recently published. Each page makes up one topographical ring of the lake. Put them all together and you’ve got a really amazing way to explore the watery depths of the deepest lake in the United States.

The book you see above is hand made. She downloaded the depth data from the US Geological Survey, then put it through some processing in order to print one elevation level on each page. That’s when the work really began. She cut out every page by hand! The four-plus hour task was grueling. And just for a bit of added punishment she even made a second book. But at Tuesday night’s follow-up presentation she said never again.

[Caroline] developed a much faster and still accurate technique for producing the bound-book depth maps. She is using a laser cutter and a different binding technique. By using folded packets of paper, rather than individual pages, she is able to cut out three double-sheets at once — including holes for the binding thread and the outline of the finished pages themselves. This cuts the process down to about four minutes of laser cutter time.

For now you’ll have to settle for a time-lapse video of the hand-cutting process (embedded below). But we hope to post an update when she makes more information about the laser-cut version available.

Continue reading “Making A Bathymetric Book By Hand And Searching For An Easier Way”