Computational photography[1] is getting really, really cheap. You can do things with arrays of cameras, like see through shrubbery.[2]<p>Add in cheap controlled motion (think $200 CNC engraver machines) and you can build a comparator[3] to do precision measurements that used to require expensive machines.<p>[1] <a href="https://graphics.stanford.edu/projects/array/" rel="nofollow">https://graphics.stanford.edu/projects/array/</a><p>[2] <a href="https://graphics.stanford.edu/projects/array/videos/crowd0-sap.mpg" rel="nofollow">https://graphics.stanford.edu/projects/array/videos/crowd0-s...</a><p>[3] <a href="https://www.instructables.com/Comparatron-an-Affordable-Digital-Optical-Comparat/" rel="nofollow">https://www.instructables.com/Comparatron-an-Affordable-Digi...</a>
ASIC fabrication is being democratized... I look forward to getting a chip through TinyTapeout in 2025. I've had a long term itch to build a different type of compute engine... and now I get my chance for $150 and a lot of time. 8)
Software defined radio is great stuff. I've been helping a friend on the other side of the technology curve, he's been repairing things since the 1950s, and we've done a ton of Tube and early transistor stuff... 100 pound boat anchors can be replaced with functionally superior boxes the size of a large USB stick.<p>GNU radio is open source, and will work with your audio ports... so you can shift audio up/down in frequency, make a sonar, etc... all for free, and in your spare time. Add in a $30 RLTSDR dongle, and you can receive almost anything.
How <i>cheap</i> storage is getting. Given the Internet Archive's legal troubles, the ability of anyone to have a (admittedly comparatively small) web archive might be important. (I think all the books have been mirrored to piracy websites by now, so it's just websites, films, audio and software that might be in danger.)