Stamp backup battery
Hi,
I would like to know what battery , size and amps i should use to keep a stamp running and not loosing the data.
During the normal operation, a value is incremented eve 4 minutes. At this moment, i just write that value to the memory and in case of power failure i read it back at boot and use it again.
Writing is not a good solution due to the limitation of number of writes on the stamp memory.
I would like to know if it is possible to use something like a watch battery just to keep the variable on the stamp without writing it on memory. Something similar to the battery used on real time clocks.
I do not need to use any display at power off, just to keep the actual value and the stamp to keep running , but no collecting any new data, like a sleep mode.
Thanks
Ion
·
I would like to know what battery , size and amps i should use to keep a stamp running and not loosing the data.
During the normal operation, a value is incremented eve 4 minutes. At this moment, i just write that value to the memory and in case of power failure i read it back at boot and use it again.
Writing is not a good solution due to the limitation of number of writes on the stamp memory.
I would like to know if it is possible to use something like a watch battery just to keep the variable on the stamp without writing it on memory. Something similar to the battery used on real time clocks.
I do not need to use any display at power off, just to keep the actual value and the stamp to keep running , but no collecting any new data, like a sleep mode.
Thanks
Ion
·
Comments
Although the Stamp doesn't use much power in sleep mode, this is probably a simpler solution since it doesn't require any backup power and you don't have to be able to switch off the display and other devices.
Mike, i got confused here. How i can make the stamp to change the location for each day / I do not have a real time clock
Thanks
SRLM,
do you have any sugestion where to lstart looking ?
When i google , just return UPS and this are to big and expensive.
Thanks
http://schematics.dapj.com/2006/10/battery-backup-for-sram-or.html
Post Edited (remmi870) : 3/14/2009 9:20:50 AM GMT
"and the stamp to keep running , but no collecting any new data, like a sleep mode."
You do know that the Stamp does in fact have a SLEEP mode? In SLEEP the current drain of the Stamp drops to around 50 microamps, and if you have it hooked up with a sense and switchover circuit per other advice here, then something like a 4.8 volt NiMh phone battery on trickle charge could hold it for quite a while until the main power is restored. The Stamp won't reset until the voltage drops below about 4.2 volts.
Another solution is to add external non-volatile memory such as a FR25040 (www.ramtron.com, Mouser), or a battery backed clock chip.
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Tracy Allen
www.emesystems.com
I appreciate a lot all of your efforts to help me on this problem. I read all the support comments and i will try to implement the sleep mode in conjunction with one of the suggestions received or using an Intersil ICL7673 chip. It does the voltage monitoring and provide the switching signal.
Once again Thank You
Ion