i’m going to help a friend get some electrical panels going, he is (or used to be) a chartered engineer so no worries on safety. I have undergone training as an electrician as well
but the Q is… using an external drive to store data on, is it worth it spinning down the disk and only write every half hour and use either memory or the sd card as temp storage?
another thought… are there an option to spec how much storage can be used to store data and when full just overwrite the oldest data with new data?
Otherwise, there’s a chance of not being able to spin it up afterwards. (called stiction) I’ve seen it happen to more than one drive, so whle it might not be a common occurrence, it’s still something to think about.
I’ve found it an ideal use for the SSD’s I’ve got that are now too small for other purposes. Put them in a USB enclosure and you add zero noise and only a small amount of power consumption to your install. Also no problems of stiction (ok, so there is “wear” problems instead…). You can buy 120GB SSD’s for as low as $40 AUD these days.
Heading off topic but on the subject of stiction, I fondly remember the days of having to restart some of the mips servers running the rod rolling systems at the steelworks I worked at. Stiction was a regular issue on those 100MB (yes, MB) drives and I quickly got the knack of opening up the server case to tap the HDD in exactly the right place with the handle of a screwdriver to break the stiction so they’d boot up
not sure if the location where data is saved are still the same, but how would it tell the system to save data another place? example would be that i mount my external ssd at /mnt/ext
I still have the SD card in, but only to boot off - its essentially never written to.
You may have to play around with mount points if you’re moving an emonpi SD card image but there’s no reason you can’t move everything onto the one mount point if you know a little about linux and /etc/fstab
