But overall, I get the feeling that people today are afraid of things they can't vendor out, things they can't replace cookie-cutter style. Sometimes that concern is justified, when you think in terms of support spanning decades, but overall I see it as a vertical integration of bureaucracy all around us.
It's not just this control system, it's everything. Was it Caltrans that hit a modernization roadblock because the agency hand-built railway sensors and circuits around that same time and now can't find replacement parts because people don't build things in-shop anymore?
What remarkable faith? It's a program to start/stop AC/heat units based on temperatyre readings, not to send people to Mars.
A talented high school student can write one today, and do it with a Rasberry Pi and for much less than $1 million (more like 5-10K).
Not as a student, but as a temp in a secondary education unit, I maintained and updated the payroll system used to pay ~50 schools and over 1000 teachers every month. It was a VB/MS SQL thing written by another temp a few years earlier, but it did the job.
Yes, these things can all be done by amateurs. By tinkerers. We all here know it. We've done it. You've done it. Simple devices with telemetry and some logic. Simple programs that do complex things in the aggregate. Take it to your back yard, and either one of us or a highschool student could make a traffic light cheaper than $250,000 - $500,000 per intersection (WA state estimate). But neither one of us could build, install and maintain a quarter million of them, and I think you'd be hard-pressed to mobilize an army of nerds to make it scalable.
Yeah, for all we know a PE was involved in oversight of the project. That's an unknown that TV reporters didn't dig into and should have, because I think the story would discover a much more relaxed time.
But if one wasn't involved, I'm saying it took faith on behalf of the administration to assume responsibility for risk in backing this project, whether consciously considered or not. And there are risks with electrical projects beyond the computers, namely things catching on fire. What were the safeguards here? What if a logic error burned out a fan? What if someone hesitated to use the radios during a regular comm window out of habit and there was a medical emergency?
Faith here was well-founded because obviously nothing burned down and no one died. But who today would accept that risk without going to a licensed professional?
Well, in the real world it didn't matter at all.
The payroll sheets were then sent to the state's revenue service so that teachers would get paid. If there was an issue, the revenue service would spot it.
Occasionally there were a few slips, because this or that law regarding teacher compensation, insurance contributions etc changed 2-3 times a year. We'd just calculate the differences and issue correction invoices to compensate. At worst a teacher would get a month's salary when they shouldn't (e.g. they have stopped working, but the school didn't notify in time), and then have to give it back.
>Yes, these things can all be done by amateurs. By tinkerers. We all here know it. We've done it. You've done it. Simple devices with telemetry and some logic. Simple programs that do complex things in the aggregate. Take it to your back yard, and either one of us or a highschool student could make a traffic light cheaper than $250,000 - $500,000 per intersection (WA state estimate). But neither one of us could build, install and maintain a quarter million of them, and I think you'd be hard-pressed to mobilize an army of nerds to make it scalable.
The story is not for "a quarter million" of traffic lights, though (which would require tons of money, installations, construction work, big material orders, etc), but about an AC/heat controller for a school district.
Such things as the latter, a "tinkerer" can often do much better, faster, and more effectively than some "specialized" firm.
>But if one wasn't involved, I'm saying it took faith on behalf of the administration to assume responsibility for risk in backing this project, whether consciously considered or not. And there are risks with electrical projects beyond the computers, namely things catching on fire. What were the safeguards here? What if a logic error burned out a fan?
The student didn't install the AC/Heat units themselves.
And the school could always have a "licensed professional" come and check the student's program for correctness, for 1/10th or less of the cost of a 1.2 million dollar replacement, how about that?
Back then, you could do things more freely with less capable and available hardware. Different environment. Concept of computers was scratching the surface of what they could do for us, and people didn't have a notion of liabilities. And yes, the student didn't install the HVAC systems, but how did tele-operated harwdware interface with it? They didn't have echo dots and knockoff power plugs back then.
Today, you have all that available hardware but can't realistically do things as freely. Suffice it to say that the environment has clammed up on all fronts for an amateur to enter an industry. In some cases rightfully so (only experts for surgeries, plumbing and wiring for me please). In others, egregiously wrong barriers. For example, commonly the first thing that happens in a public institution or agency is that the losing bidder files FOIA requests trying to litigate why their solution was passed up and by whom, including copies of correspondence between them. Imagine having to deal with that dimension.
Back to traffic lights: for something so rudimentary yet so vital, it costs millions of dollars for a handful of intersections, and they're everywhere. Nearly a prime candidate for a four raspberry pi solution, right? You'd think someone would have attempted it.
I agree, and I think that's the key insight in all this. For some things the extra legislation, rules etc make sense. In many other cases, they complicate things, and can even end up delivering not just a costlier but also a less effective outcome (e.g. the 100M government website when a 2-3M one made by a small team would do better).
The rest is the actual cost of the product.
Outside of interesting questions like whether amateur tinkerers and hobbyists can be as reliable as professionals are other (also interesting) questions like "what factors drive the way institutions and corporations perceive and react to risk?"
> A talented high school student can write one today, and do it with a Rasberry Pi and for much less than $1 million (more like 5-10K).
Yes, writing a bang-bang controller would be trivial. Even some kind of PID controller wouldn't be too hard for an enterprising high schooler to try.
What makes the professional systems valuable is that they can build much more accurate models of how the building heats and cools. These models depend on the building's geometry, usage patterns, outside climate, etc., and are notoriously hard to produce. However, they can produce meaningful savings over long time periods since they ultimately use less energy due to the quality model.
Older electrical meters weren't all that accurate, especially for larger systems - that's true even today. They're analog as an only option of measurement due to incredible amounts of power going through them (too noisy for hall effect sensors). Large buildings are reactive loads to the grid, almost like an inductor. Anyhow, older meters picked up velocity for usage calculations.
Some A/C controllers carefully modeled how fast the power meters accelerated as an instrument, then used that information against them, throttling and ramping power use to slow the measurements down, basically causing under-metering.
Saved USPS millions a year in power bills.
That's one way to view it, another point of view would be that all those people whose jobs we're automating away still get to work somewhere doing something.
Read only file systems on the SD boot volume are another solution, but this can cause other headaches (obviously) or may not be appropriate for the software you intend to run.
It’s been running 24/7 in my garage since 2014. YMMV I guess?
[1] https://github.com/Dan-in-CA/SIP [2] https://github.com/andersix/sip_garage_plugin
Getting it all into a software state that can easily be transferred to "something that runs Linux and this emulator that requires next to nothing" certainly seems sensible at any rate.
Samsung EVO SD card, have multiple times rebooted by pulling the power (which is not ideal) because of unrelated issues that were due to some OS problems (SSH doesn't respond, etc) without a problem, but haven't had to do that in a long while after changing the OS and getting NIC stuff set up properly.
I have seen that the majority of SD corruption that happens tends to be in situations where Pis are being run under-powered off of a USB hub or something similar instead of a wall-plug.
I believe with a decent-quality SD card, and properly powering the Pi, the chances of SD corruption are relatively low. That said, I would prefer a USB3, SATA, NVME, or even eMMC interface, but the Pi has worked remarkably well for me. USB2 booting the Pi is always a backup option if my luck takes a turn for the worse
It is something I worry about though.
Unfortunately not all SD cards, even if advertised as the same capacity, are exactly the same size. If your replacement card is just 1 byte smaller your dd clone won’t restore - the “free” space has to fit into the target card as well.
Long story short - most popular methods of cloning microSD cards for the Pi only ensure the ability to restore to a larger SD card, not necessarily one of the same advertized size.
For sure there are workarounds, but it’s not as straightforward as you might assume. Personally I’m much more a fan of other tools such as rsync or version control etc for cloning data to and from Pi projects.
The better answer is just to USB boot the Pi anyway - they’ve supported this for a while now, no card corruption issues to mitigate.
https://www.makeuseof.com/tag/network-boot-raspberry-pi-with...