Physical lock

This is an example application built on the Vanadium stack.

Development

Conventions

• The name used to claim a lock cannot contain slashes. It is also the blessing name that the lock subsequently authenticates with.
• A key to a claimed lock is a blessing with a name matching the pattern “/key”

Features to add to the Lock server:

1. Auditing: This is one of the strong features of our model, so I‘d imagine that we’d want a:

AuditLog(startTime, endTime time.Time) []AuditLog | error
type AuditLog struct {
  Blessing string
  Action LockStatus
  Timestamp time.Time
}

We'd also have to work out how to control access to this AuditLog. One option is to use caveats - so when “making” a new key one can choose to insert the “noadmin” caveat?

Features to add to the Lock client:

1. Support more caveats in sendkey

• TimeRange Caveat
• AskForPermission Caveat

Circuitry with the RaspberryPi

Equipment

• 10KΩ resistor
• 1KΩ resistor
• Magnetic switch (normally open circuit - closed when the sensor moves away) (e.g. P/N 8601 Magnetic Switch)
• For now, an active buzzer to simulate a relay. Will fill in the relay details here once we have that setup.
• Breadboard, jumper cables, ribbon cable - or whatever is needed to connect to the RPi's GPIO pins

Circuitry

Apologies for this unconventional, possibly unreadable circuit representation. Putting it down so that the author can remember! TODO(ashankar): Clean it up!

The pin number assignments here work both for RaspberryPi Model B/B+ and RaspberryPi2-ModelB.

---(Pin 1)-------/\/\(10KΩ)/\/\---------(COM port of magnetic switch)
                                  \
                                   \----/\/\(1KΩ)/\/\---------(Pin 15 = GPIO22)
                                                          \
                                                           \----(LED)-----|
                                                                          |
                                                                          |
                                          (N.O. port of magnetic switch)--|
                                                                          |
                                                                          |
                                         (-ve terminal of active buzzer)--|
                                                                          |
                                                                          |
                                                                          |
                                                           (Pin 6 = GND)--|

---(Pin 11 = GPIO17)-----------(+ terminal of active buzzer)

Deployment

To build for the RaspberryPi setup with the circuitry mentioned above:

v23 go get -u github.com/davecheney/gpio
V23_PROFILE=arm v23 go install v.io/x/lock/lockd
scp $V23_ROOT/release/projects/physical-lock/go/bin/lockd <rpi_scp_location>

If building without the arm profile, there are no physical switches/relays and instead a simulated hardware is used that uses the interrupt signal (SIGINT) to simulate locking/unlocking externally.