I have made this with a lot more problems than I expected.
In fact, after I had started it I felt that I really didn’t need it.
Like my earlier Color TfT clock it displays my passwords securely.
My master Password Safe is from China – recZone. It’s OK but takes at least 10 button presses to get a password.
The Color TfT clock is easier to use but the big graphics display takes about a second to write.
To edit its data requires editing its micro SD card, which I hate, and unscrewing the end cap.
Besides it is full and not easy to find the desired entry. This is the new one:
The Secure Digital Card Password Safe uses a full-size SD socket, which I had to buy direct from China, since Adafruit and Sparkfun only offer micro sockets.
To edit, the card just is pulled up out. Because of the telephone-type keyboard it is easy to locate the entry, and there are no quantity limits.
I originally built it with a Pololu A-star Prime LV so it could be run off a single Li cell directly.
But it crashed with the service program and continually lost its USB connection.
This new device is fast, easier to use, and does not have any problem programming.
I had to rebuild it with an Arduino R4 Minima which has 48 Mhz and a quarter meg flash. It is very fast and uses only 30% of its memory. But now it needs 2 cells, a startup and hold circuit, and a battery voltage sensing circuit.
The Color TfT Clock has two functions:
1. Display the codes in the protocol of my home-made home automation system. About 48 codes.
2. Display my web access passwords.
The color TfT clock defaults to #1 and only shows the alternate password screens when a “dongle” is inserted into the power input socket. Its web page does not describe these functions.
The Secure Digital Card Password Safe only does option 2.
Naturally security is paramount for displaying passwords. In addition to removing the dongle in the case of the TfT Clock or the secure digital card in the present project, both the Color TfT clock use this additional method:
There are two parts to assembling the password. The SD card contains files containing rows with the name of the site. Instead of including the actual user name and password each line starts with 3, 2-dight numbers,
These are indices to arrays in the program.
The first array and number contains a list of user names.
The second and third are catenated parts of the password. Many, but not all, include the common requirements of both upper and lower-case letters, plus one or more numbers and symbols.
Most passwords are at least 8 characters. The second array is by definition random, being copied from parts of old vehicle number plates from many states and years.
Note that the array in this web page has been scrambled from that in the service program.
Since this device is so easy to use, each site has a unique password. The SD card is easily removed for storage in my safe.