boarduino w/ coin cell back up

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mtbf0
 
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Joined: Sat Nov 10, 2007 12:59 am

boarduino w/ coin cell back up

Post by mtbf0 »

i've got a boarduino clock project and have recently become covetous of the coin cell backup used on the icetube.

seems like i could add this to my clock by hooking up the coin cell and diode between vcc and ground and maybe replacing the power select jumper with a diode from pin 1 to pin 2.

do i screw things up by placing the diode on the other side of the filtering caps? would i be better off trying to solder it to the bottom side of the board between the regulator and the caps?

then i guess i'll have to switch the power to my lcd through a transistor and compare vcc to the mega168's 1.2v reference to figure out when to go to low power mode.

am i dreaming? delusional?

adafruit
 
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Re: boarduino w/ coin cell back up

Post by adafruit »

its possible. make sure the chip can run as low as 3v. look at the code and schematic to see where to put the diodes. you need to protect the 7805 from the coin cell and vice versa. where exactly its put is not so important

mtbf0
 
Posts: 1645
Joined: Sat Nov 10, 2007 12:59 am

Re: boarduino w/ coin cell back up

Post by mtbf0 »

thank-you.

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