Hi George,
A 555 will switch all relays off at the same time. Its datasheet is here:
**broken link removed**
It will draw 4mA to about 10mA all the time it is connected to the battery.
Since it needs a series diode to protect it from the flyback voltage spike from the relay coils and since it has an output voltage loss of up to 2.25V,
a 9V battery is needed to power its circuit.
Since most 5V relays are guaranteed to operate with a voltage of 3.75, the circuit will still work when the battery voltage drops to about 7V.
A 555 will switch all relays off at the same time. Its datasheet is here:
**broken link removed**
It will draw 4mA to about 10mA all the time it is connected to the battery.
Since it needs a series diode to protect it from the flyback voltage spike from the relay coils and since it has an output voltage loss of up to 2.25V,
a 9V battery is needed to power its circuit.
Since most 5V relays are guaranteed to operate with a voltage of 3.75, the circuit will still work when the battery voltage drops to about 7V.