Grab Bag of Questions

NateSebold

New member
I got a brand new 4.3 to go with my 4.2 for xmas. I am rethinking and re-imaging all my sdcards and the versions of Raspberry pi's that I have to go with each and have a few questions.

First is about the
USB Mass Storage wifi configuration
A USB mass storage device (USB stick) can also be used to configure the wifi on bootup. The boot process looks for a config.txt file on the USB stick with the same format as above. Copy / paste the example above, edit it to match your network settings, and save it to your USB stick as config.txt. Insert the USB stick into the Pi and boot. Compared to the normal config.txt processing, the configuration here is not disabled after use so the same USB stick can be used over and over. This is also an easy way to switch between AP mode and client mode without needing to access the microsd card.
Does this process rewrite the exisiting config info or would it only load if the config.txt/usb stick was present? - Most of the time I would want to run on client mode so could I throw an old usb in my smoking toolbox with the config.txt/usb stick for AP mode and whenever it is interested on boot it would boot to AP and whenever it was not inserted it would use the "exisiting" client config? Could i have a config.txt/usb AP key so to speak? If this works I would assume I need a seperate "key" for each one or would the key be interchangeable between 4.2 and 4.3?

I did an inventory on all my sd cards and I'm hoping that the slowest and smallest would be fine for both the 4.2 and 4.3. Here is what I have:
8gb card with 6MB/sec Write and 74MB/sec read
2gb card with 5.6MB/sec write and 22MB/sec read
16gb card with 3.5MB/sec write and 21.2MB/sec read
16gb card with 9.9MB/sec write and 43MB/sec read

Would all of those be sufficient?

I currently have two raspberry pi's but am thinking about getting a third. I want two to run each of my heatermeters and I would like one to run my as of not yet built magic mirror. Here is what I have:

Raspberry Pi 1 Model B revision 1.2 using Trendnet tew-646ubm for wifi
Raspberry Pi 3 Mobel B v1.2

Bryan wrote this on another forum about recommendations:
Summation:
-- If ONLY wired Ethernet is needed: Raspberry Pi 3B
-- If wired Ethernet and wifi is needed: Raspberry Pi 3B+
-- If ONLY wifi is needed: Raspberry Pi Zero W or Zero WH
I suppose I would like to get a Zero WH for the HM4.3 because I do like to run on batteries sometimes and the lower power footprint seems nice to have. That would leave my Pi 1 to go with my HM4.2 and then the pi 3 to go with my magic mirror.

Anyone see any flaws in this plan?

Thanks for your time!
 

Bryan Mayland

TVWBB Honor Circle
Does this process rewrite the exisiting config info or would it only load if the config.txt/usb stick was present?
It is the same as the config.txt on the SD card in that regard. It overwrites your existing configuration with the config from the mass storage device. The difference is that the config.txt on the SD card is "commented out" so it only works once, but the mass storage stays active so every boot it will overwrite the active configuration. The idea there is that it lets you use it over and over as needed to swap between different configurations without having to go back to a computer to re-enable the config in the file.

So yeah your idea of having a "client mode" USB drive and an "AP mode" USB drive is right on. Just put in the one you want to be active before boot. The same USB stick can work on 4.2 and 4.3 without modification.

I did an inventory on all my sd cards and I'm hoping that the slowest and smallest would be fine for both the 4.2 and 4.3. Here is what I have:
All of those are fine. The SD card is only used at boot time really, once it is fully up and running (~30 seconds from power on), it runs the database from a ramdisk and all the applications are loaded into RAM / cache. You might see ~1s difference between the world's fastest U3 / V90 SD card and a class 2 SD card. The HeaterMeter boots in milliseconds and begins control after 1 second so you might not ever notice that the Pi takes 31 seconds versus 30 seconds to fully boot.

I suppose I would like to get a Zero WH for the HM4.3 because I do like to run on batteries sometimes and the lower power footprint seems nice to have. That would leave my Pi 1 to go with my HM4.2 and then the pi 3 to go with my magic mirror.
That's the way I'd provision it too, given what you've got and what your plans are. The Zero is a great 4.3 host board, the Pi 1 can really only be used on a 4.2, and your most powerful Pi 3B will see its best use running all the smart mirror services.
 

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