In SX Microcontrollers, SX/B Compiler and SX-Key Tool, william wrote:

Kramer,

There is no rush of current from the solar panel (small one) that the supercap cannot absorb easily, since the panel is always connected to the supercap.  There is no switch.
Yes, if your solar panel has no blocking diode, you need to add one.
If you use a 7805, it will leak 3mA even when there is zero load.  This is unacceptable.
Even a very good regulator may leak 500uA when there is no load.

John,

If you run the SX at 4Mhz, it will only consume about 5mA of current, 1Mhz will be even less current.
Use any one of the SX's IO pin to directly power the eeprom. No need for transistors.
This way, before the SX goes to sleep, it can literally power down the eeprom  first.
Assuming the board has only the SX and the eeprom and no regulator, the total sleep current would be less than 5uA.
At 5uA, lets hope the 1 Farad capacitor can last the whole night.
To save power at night, use the watchdog to wake up the SX every 2.5 seconds.
Then quickly sample your data in a few milliseconds and then go back to sleep.

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