How do I make my HD account a read Only acccount so know one can send from it,[...]
Coming up soon:
Devs:
How do I find xpub key?
in the next beta version 2.2 which is planned in january.
seems like anyone who has access to my phone has access to my bank... Only thing separating them is a simple pin just does not seem safe.
[...]
That "simple" PIN is 6 numbers, resulting in 10^6 possible combinations. I don't know how many tries you get with Mycelium though, hopefully it's coded in a way that make the time between trials longer if you entered the wrong PIN more than, say, three time. Additionally you can put a key lock on your phone. Depending on the model this can be a PIN, passphrase/password, or a something like a line drawing. Some phones offer full encryption as well.
If your phone is stolen, all of the above should give you enough time to restore your wallet and send the coins to a new address on a different phone or computer. (restore instructions:
https://bitcointalk.org/index.php?topic=909238.msg10003275#msg10003275)
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I liked it when I had my old account and Id have to scan the QR code if I was to send from my physical SAFE account, [...]
This is still possible to do, even with the HD version. Go to Accounts, tap the Key+ symbol, tap Advanced, enter PIN and scan the address you'd like to receive coins to (with the private key saved somewhere else). Back in the Accounts tab, select the address you'd like to work with.