"I am interesting in participating in designing and building one. It helps me to set a norm of speaking concisely and to the point, as reading can be hard for me when working. I am sorry if I have skimmed over something already said. Have you started any projects?"
I've done a substantial amount of electronics in the 1970's and to the early 1990's, but I haven't done an electronics project since then. Not that I couldn't pick it up quickly: The major thing I'm missing is knowledge of the current set of devices available and construction techniques.
I designed and built a constant-temperature bath in the ealry 1970's, also a 4-digit audio frequency counter, also a 4.5 digit digital voltmeter. In 1977 I built a "Dyna-Micro" microprocessor trainer, from the design in Radio-Electronics magazine.
https://en.wikipedia.org/wiki/Single-board_computer
Starting in 1978, I designed and built my custom-bus Z-80 microprocessor computer which at one point had about 600 IC's, mostly wire-wrapped. My father and I set up the ability to make 2-sided PC boards around 1972, but since we couldn't plate-through the holes, actually assembling such a board was a bit tedious. I built two 32K by 8 DRAM cards using Motorola 4k x 1 6605 DRAM chips, later replacing them with static RAM.
https://datasheetspdf.com/datasheet/MCM6605A.html In hindsight, I decided that I should have used one of the 16k x 1 DRAMs that had become available.
In 1990, I designed and built a device which used 76 IRLEDS to flash, activating the Opticom traffic control system to turn red traffic lights into green traffic lights. Had I gone into major production, I would have used as its motto: "It's the most fun you can have in a moving car !!!".
HOW I FORESEE THE PERSONAL BLACK BOX:
I see a central box, about the size and shape of a common smartphone, but with no user interface. It will include connectors to:
1. USB, to a standard, commercial smartphone.
2. To the camera stack, 4-6 HD cameras. (About 3 gigabytes per hour per camera.)
3. To a battery pack.
4. To a SSD. At 3 gigabytes/camera/hour x 6 cameras, about 18 gigabytes per hour. So, a 1 terabyte SSD should be sufficient, if its data transfer rate is enough.
The central box will probably include 2-3 multi-core microprocessors, and its main task will be taking the data outputs of the cameras, compressing them, and sending the result to the SSD.
It will probably not be possible to send more than a tiny fraction of this data directly to the Internet, so I anticipate sending maybe 1 frame/second for each camera, to be stored remotely. I've read that eventually, 5G technology will be able to transfer 10 gigabits/second, but I doubt that this will be kept up in a crowd of thousands of people, many of whom will be using their own cell phones.
The smartphone might also be linked to a nearby confederate (is that word too anti-PC these days?) by WiFi, whose system might mirror as best as possible the video material being collected. One goal is to ensure that complete destruction of the system will not lose all the data collected. If the location of the event was anticipated, perhaps a remote data-collection box could be installed, which would act as a safe data backup.
The actual control of the camera system might be done remotely: The person wearing the system shouldn't be expected to do anything other than being a camera platform.
This kind of system would probably have an even bigger market to journalists and news crews. I don't expect it to substitute for traditional video cameras, but its presence would tend to guarantee that most information gets collected. It would tend to protect the news crews, because it would store a record of any attacks on them.
Jim Bell