In HW revision 0.3 the sleep pin is without function.

Instead there is an auto-sleep circuit onboard, that will make the board sleep when not actively driving SET or RST high.

To switch the relay on, it is enough to only drive the SET pin high for 10ms (while RST is in high impedance or driven low).

To switch the relay off, it is enough to only drive the RST pin high for 10ms (while SET is in high impedance or driven low).