It was the PicoPSU90, it was the M4-ATX. :)
Starting with the PicoPSU90, life was good until the power dropped. It was cool how a desktop PC could, in fact, be made to run on 12V. The thing was very small and generated little heat while doing almost everything I needed it to do, but it was sensitive to voltage. It was designed for rooms with clusters of machines all running from 12V lines, not vehicular use.
Once in a while someone pulls the 110V line where I'm docked to mow the lawn. Eventually I'll be pulling it myself as part of the undock-sequence. The old supply would run only for a short time on batteries alone; it had a narrow range of operating volts. It needed to work when the 110 was there, but also a reliable amount of time on batteries alone. The idea was, after all, to send-for-help if the trailer was stolen. I'd just be happy if it'd email me to let me know the power cord had been pulled.
A year or two later I had the money for the M4-ATX. It had serious terminals for power, had to be wall-mounted, and a manual that was far from complete. It also has a voltage range of 6-30V. I was looking forward to seeing just how long it took my garden-variety battery to drain to 6.0V.
Well it's around 20 hours, actually. And when it went down, it took the motherboard and hard drive with it. While it showed a cable connecting the power supply to the "power switch" pins to turn off power at the right time, I didn't know it was required; I'm also not using the "ignition" line, because I don't have one. I had to extend the line, another test is planned for sometime soon. I have a good feeling about the outcome, now.
One of the nice things about running an all-circa-2002 design for this application is that all the major bugs are out; you can read the sensors, the BIOS is as up to date as it'll get, and things go together well. While things may have been undecided back then, now Linux sees them for what they were trying to be, despite every manufacturer trying to corner the market in each and every possible way.
Like ACPI, the power-down sequence when the machine senses it's idle. Before 1999 *everyone* wanted to corner the technology. So no one's machine actually worked. Linux' kernel turns off ACPI at all for machines before 2000, for just such a reason. And by now, every tweak of every driver has been made. While they're old, and I wouldn't use them on a NASA mission, they're perfect for here.
An example of the settled technology is the view of the power supply and compartment temperature from a remote machine:
Life's pretty good now, both having the proper PSU and being able to monitor it from another room. (Or county) But there were some lessons learned:
- Mini-Box has good components at fair prices
- Mini-Box has documentation that needs work(!)
- Make sure to get the wide input range for ANY vehicle use
- Expect a month of emails if there's trouble with Mini-Box
- Despite the manual suggesting otherwise, their tech-support email is " This e-mail address is being protected from spambots. You need JavaScript enabled to view it "
Now that the power supply is doing it's job, and the parts are coming together, life's pretty sweet!
