Sprinkler timer using SequentMicrosystems stackable 8-relay board(s) on a Raspberry PI. This is a work in progress.

The relays are controlled by communicating with the onboard I2C device, using the "i2c" Linux kernel driver.

This code is/was reverse engineered by running the 8relay binary from SequentMicro with:

strace -e open,read,write,ioctl 8relay ...

Basic library usage:

r, err := i2clib.NewRelay(bus, board)

Open a channel to relay "board" on i2c "bus"

• The usual bus for a Raspberry PI is "1"
• The board, with no address jumper pins installed is "1"

r.Set(i)

Set the relays based on the bit mask i (0 - 0xff)

r.Get()

Get the currently activated relays (e.g. r.Set(i);r.Get() should emit "i")

r.Close()

Close the channel

Build "sample" programs:

• go build cmd/basic/relay.go Relay sets or reads the state of the relays on a daughter card
• go build cmd/sprinkler/sprinkler.go Sprinkler activates a sequence of sprinkler zones in the provided sequence and timings, suitable for running via cron for unattended operation.