This circuit is from an old Mullard (Philips) manual with applications using the 555. Choosing appropriately the resistors and the timing capacitors, the ranges obtained can exceed days.
This circuit was found in an English magazine Radio & Electronics Constructor of February 1977....
This circuit is from a 1976 documentation. The diodes can be 1N34 or equivalent, and the power...
This circuit is from a Maxim manual and can be used to power shields from batteries. The circuit...