Joan M wrote: ↑
Mon Dec 31, 2018 2:53 pm
I want to use a Raspberry Pi 3 B+ to monitor several sensors and show some counters in a big TV that will be placed at 3 meters height.
That Pi won't have any keyboard neither a mouse connected.
I want to be able to remove power to shut it down.
My Questions are:
1. USB DRIVE SAFER THAN SDCARD?
I know that I can corrupt the SDCard and therefore have problems if I remove power without shutting the OS down before. Some IT guy has told me that if I use a USB drive to boot from that risk is eliminated and that I can remove power directly.
Is that right? from my point of view that has no sense, but it's worth asking it here where the real experts in Pi are.
It is never a good idea to shut a computer down by turning off the power, unless it is specifically designed to tolerate this (i.e. runs from a readonly file system and does not write to any files other than 'throwaway' temporary ones on a ramdisk). SD Cards are particularly prone to problems if powered off while (or very shortly after) being written to, but files written on any storage device can end up corrupted and/or unreadable if write operations are not completed properly before the device is powered down. If you are only interested in displaying current data, and are not planning to store anything (or are storing what you need to store remotely), there are a number of ways of setting Raspbian up to boot from an SD card but run with a readonly file system.
2. APC UPS SYSTEM?
I can put an APC UPS system to power the raspberry and put a selector that removes power from the UPS system... If I do this I'll get the APC ups shutting down the PI and then shutting down itself... That would keep the Pi safe.
That APC UPS would be connected to a USB port of the Pi.
That would certainly work, but is a more expensive and space-occupying option, and also depends on no-one deciding to turn off the UPS from its power switch, if it is within reach, and/or requires the installation of a shelf or something similar to support the UPS if it is right next to the TV.
3. ANY OTHER OPTION?
I want it to be able to shut down properly in case of a power loss.
There are some specifically Pi-oriented mini-UPSes available, but they are not hugely cheaper than the smaller APC models.