[quote="rtek1000"]I would like to do a layout with super capacitors only to safely shut down the Raspberry.
For the case of missing local electricity network.
But I noticed in video that you need to use large size and high value capacitors:
Maybe if use a regulator, the charge of the super capacitors can be better utilized.
like this: http://www.dx.com/p/usb-dc-3v-to-5v-vol ... red-146765
I tested the minimum operating voltage of the Raspberry Pi model B: is about 4.05V. I login with Putty to test.
I buy this one: http://www.ebay.es/itm/181354720854?ssP ... 1439.l2649
It's not necessary a really big capacitor only for safe shutdown.... for 15/20 sec. a super cap of 10/25F 5.4v. (test in progress..) I think will be enough.
The only problem with this circuit (if it's works...
is ... if come back the electricity after the shutdown process but before the super cap has complete de discharge, the raspberry will remain power off.
Could be interesting find a way, in this case, to short p6 pins to reset and 'wake up' the device.
...and for this reason, you can't use a really large capacitor.... because when power off raspberry consume more or less 100mA... and abig capacitor can provide energy for up to 8/20 min.