battery backup
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Posts: 46,084
Does anyone have a battery backup circuit for the stamp that they are
willing to share?
willing to share?
Comments
>willing to share?
How about:
power 1 --->|---;
|
1N4001s o--- Vdd
|
battery --->|---'
Vss common
-- regards,
Tracy Allen
electronically monitored ecosystems
mailto:tracy@e...
http://www.emesystems.com
> I have a stamp powered device with a clock chip and a few other IC's
> in which I would like to add a battery backup. I am just looking to
> eliminate brown outs and short term power outages, nothing long term. I
> have tried adding a 4700uf cap but it only gives me about 2 seconds worth
> I was looking for about 10 seconds. The voltage is 5 volts. Is my best
> approach a battery and some type of charging circuit? Any
> recommendations on such an approach? Or I guess I could just add more
> capacitance on the 5 volt line.
Just a Thought:
In a data logger project I worked on a few years ago we implemented several
power saving schemes.
One was to run a RTC (Real Time Clock) in trickle charge mode, and then
upon an event request the
RTC was powered up to read the time, and then powered back down. Other
devices on the board
functioned in a similar way such as an I2C EEPROM, only to be powered up
when it was needed.
Since this project used a PIC instead of a Stamp, even the clock speed of
the PIC was altered
through its own software. The Data-logger was only recording two ON-OFF
switches and the duration
each switch remained in a particular position. When there was a change in
switch status open/close,
the PIC would power itself up from 30kHz to 4MHz, power up the RTC; read
the time; power down the
RTC, power up the I2C EEPROM; Write the Time and Switch states; power down
the I2C EEPROM, and
finally power down the PIC from 4MHz back to a resting 30Khz. This way a
single lithium 3V battery
would last for 4 or 5 Months. Without the "Power Saving Features" the 3V
lithium would only last
a few days!
Beau Schwabe Mask Designer IV - ATL
National Semiconductor Enterprise Networking Business Unit
500 Pinnacle Court, Suite 525 Wired Communications Division
Mail Stop GA1 Norcross, GA 30071
which I would like to add a battery backup. I am just looking to eliminate
brown outs and short term power outages, nothing long term. I have tried adding
a 4700uf cap but it only gives me about 2 seconds worth I was looking for about
10 seconds. The voltage is 5 volts. Is my best approach a battery and some
type of charging circuit? Any recommendations on such an approach? Or I guess
I could just add more capacitance on the 5 volt line.
[noparse][[/noparse]Non-text portions of this message have been removed]
for BEAM robots too
Ben
Ricky Konvicka <ricky@m...> wrote: I have a stamp powered
device with a clock chip and a few other IC's in which I would like to add a
battery backup. I am just looking to eliminate brown outs and short term power
outages, nothing long term. I have tried adding a 4700uf cap but it only gives
me about 2 seconds worth I was looking for about 10 seconds. The voltage is 5
volts. Is my best approach a battery and some type of charging circuit? Any
recommendations on such an approach? Or I guess I could just add more
capacitance on the 5 volt line.
[noparse][[/noparse]Non-text portions of this message have been removed]
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[noparse][[/noparse]Non-text portions of this message have been removed]
that is my downfall, power consumption was not a concern till now. I need
to run an LCD to so my power requirements are well above 100 ma to keep the
brains alive. There are also 12 volt valves and stepper motors that may be
running. Maybe a UPS is my best bet.
Original Message
From: "Beau Schwabe" <bschwabe@a...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, April 01, 2002 9:51 AM
Subject: Re: [noparse][[/noparse]basicstamps] Battery Backup
> At 11:42 AM 4/1/02 -0800, you wrote:
> > I have a stamp powered device with a clock chip and a few other IC's
> > in which I would like to add a battery backup. I am just looking to
> > eliminate brown outs and short term power outages, nothing long term. I
> > have tried adding a 4700uf cap but it only gives me about 2 seconds
worth
> > I was looking for about 10 seconds. The voltage is 5 volts. Is my best
> > approach a battery and some type of charging circuit? Any
> > recommendations on such an approach? Or I guess I could just add more
> > capacitance on the 5 volt line.
>
>
> Just a Thought:
>
> In a data logger project I worked on a few years ago we implemented
several
> power saving schemes.
> One was to run a RTC (Real Time Clock) in trickle charge mode, and then
> upon an event request the
> RTC was powered up to read the time, and then powered back down. Other
> devices on the board
> functioned in a similar way such as an I2C EEPROM, only to be powered up
> when it was needed.
> Since this project used a PIC instead of a Stamp, even the clock speed of
> the PIC was altered
> through its own software. The Data-logger was only recording two ON-OFF
> switches and the duration
> each switch remained in a particular position. When there was a change in
> switch status open/close,
> the PIC would power itself up from 30kHz to 4MHz, power up the RTC; read
> the time; power down the
> RTC, power up the I2C EEPROM; Write the Time and Switch states; power down
> the I2C EEPROM, and
> finally power down the PIC from 4MHz back to a resting 30Khz. This way a
> single lithium 3V battery
> would last for 4 or 5 Months. Without the "Power Saving Features" the 3V
> lithium would only last
> a few days!
>
>
>
> Beau Schwabe Mask Designer IV - ATL
> National Semiconductor Enterprise Networking Business Unit
> 500 Pinnacle Court, Suite 525 Wired Communications Division
> Mail Stop GA1 Norcross, GA 30071
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>
non-volatile RAM backup sources. But then at your high current needs, it may
not be enough still. A long time ago they used to have analog power supplies
and huge 200k, 300k, 500k+ uF caps were common. I haven't seen any of these
for quite a while now.
Another method is to use a trickle charge on a battery pack of some sort.
Then use a Supervisor (or voltage detector) to detect when the voltage drops
below a certain point, and have a circuit switch power to the battery and
vice-versa.
Goto to www.digikey.com and do a search on "supervisor", then look for a
voltage detector IC that would meet your needs. They have a jillion of them
to choose from. Obviously everyone is doing it.
Another approach is to use a LM339 comparator and setup one input to watch
the voltage for a drop, the output from the comparator can be used to
trigger what needs to be done.
You can also feed the output from the supervisor IC or LM339 into a I/O pin
on the Stamp and have the Stamp turn the battery on or off too. But if your
tight on I/O pins having it run independently is probably better. You can
have the output from the supervisor or LM339 drive a MOSFET (or even a
simple reed relay if you like) or other transistor to supply power when the
main power goes down. Then switch back when power returns.
Original Message
From: Ricky Konvicka [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=u-JmEkzGHYY1dpkF1sKXmxHmlwHgad4x4qFsJWS9TvZjwAdlUr9qH7K6owQzdBOYLH6ibKJ_Yaiyqj58wgW_9Q]ricky@m...[/url
Sent: Monday, April 01, 2002 1:43 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Battery Backup
I have a stamp powered device with a clock chip and a few other IC's in
which I would like to add a battery backup. I am just looking to eliminate
brown outs and short term power outages, nothing long term. I have tried
adding a 4700uf cap but it only gives me about 2 seconds worth I was looking
for about 10 seconds. The voltage is 5 volts. Is my best approach a
battery and some type of charging circuit? Any recommendations on such an
approach? Or I guess I could just add more capacitance on the 5 volt line.
[noparse][[/noparse]Non-text portions of this message have been removed]
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
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then I will probably look at the supervisor IC's.
Original Message
From: "Earl Bollinger" <earlwbollinger@a...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, April 02, 2002 4:35 AM
Subject: RE: [noparse][[/noparse]basicstamps] Battery Backup
> I would normally try a 1,2, or 3 Farad Cap myself. They use these as
> non-volatile RAM backup sources. But then at your high current needs, it
may
> not be enough still. A long time ago they used to have analog power
supplies
> and huge 200k, 300k, 500k+ uF caps were common. I haven't seen any of
these
> for quite a while now.
> Another method is to use a trickle charge on a battery pack of some sort.
> Then use a Supervisor (or voltage detector) to detect when the voltage
drops
> below a certain point, and have a circuit switch power to the battery and
> vice-versa.
> Goto to www.digikey.com and do a search on "supervisor", then look for a
> voltage detector IC that would meet your needs. They have a jillion of
them
> to choose from. Obviously everyone is doing it.
>
> Another approach is to use a LM339 comparator and setup one input to watch
> the voltage for a drop, the output from the comparator can be used to
> trigger what needs to be done.
>
> You can also feed the output from the supervisor IC or LM339 into a I/O
pin
> on the Stamp and have the Stamp turn the battery on or off too. But if
your
> tight on I/O pins having it run independently is probably better. You can
> have the output from the supervisor or LM339 drive a MOSFET (or even a
> simple reed relay if you like) or other transistor to supply power when
the
> main power goes down. Then switch back when power returns.
>
>
Original Message
> From: Ricky Konvicka [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=qU56-C0SGXrokIDe-zmmJLQ0ezc_b6pCUPqm6X2MqYwIhXF5W2QjEps_TRX89btVAD0rqlhYCdCM28RBpsOleQ]ricky@m...[/url
> Sent: Monday, April 01, 2002 1:43 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Battery Backup
>
>
> I have a stamp powered device with a clock chip and a few other IC's
in
> which I would like to add a battery backup. I am just looking to
eliminate
> brown outs and short term power outages, nothing long term. I have tried
> adding a 4700uf cap but it only gives me about 2 seconds worth I was
looking
> for about 10 seconds. The voltage is 5 volts. Is my best approach a
> battery and some type of charging circuit? Any recommendations on such an
> approach? Or I guess I could just add more capacitance on the 5 volt
line.
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
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> Body of the message will be ignored.
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>
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>
>
>
>
>
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> basicstamps-unsubscribe@yahoogroups.com
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>
>
>
>
from the system is removed, the clock can run on it's own power. The
way to do this is to break the line at a point before the cap you have
chosen is in parallel with the chip. Put a diode in series with this
arrangement such that the anode is towards the supply source. This way
when external power is removed the diode will be reverse biased.
+ diode
|>|
|
|
| |
Power _+ Clock circuit
_ cap goes here
- | |
|
HTH
Leroy Hall
another board. I did not think about doing it to isolate the components on
one board. I think I will give this a try. Thanks Leroy!
Original Message
From: "Leroy Hall" <leroy@f...>
To: <basicstamps@yahoogroups.com>; <ricky@m...>;
<earlwbollinger@a...>
Sent: Tuesday, April 02, 2002 10:18 AM
Subject: Re: [noparse][[/noparse]basicstamps] Battery Backup
> The trick here is to use a diode for blocking such that when the power
> from the system is removed, the clock can run on it's own power. The
> way to do this is to break the line at a point before the cap you have
> chosen is in parallel with the chip. Put a diode in series with this
> arrangement such that the anode is towards the supply source. This way
> when external power is removed the diode will be reverse biased.
>
>
> + diode
>
|>|
|
|
> | |
> Power _+ Clock circuit
> _ cap goes here
> - | |
>
|
>
>
>
>
> HTH
>
> Leroy Hall
>
>
> To UNSUBSCRIBE, just send mail to:
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Body of the message will be ignored.
>
>
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>
>
>
>
some weeks ago someone posted how a battery can be connected to a stamp to
serve as a backup in case the power supply fails. It was something very
simple, I guess it was you, Tracy.
Can't find it anymore, could someone repeat it for me?
Thanks very much for help,
Uli
[noparse][[/noparse]Non-text portions of this message have been removed]
I want to implement a battery backup for a Stamp. Can I just hook both the
DC voltage supply and the batteries together with a diode to protect the
batteries? Eventually I will probably put a charger in the device and use
NiCad batteries, but for now I want to be able to use either alkalines or
NiCads that I charge away from the device. Any simple charging circuits that
anyone has would be great too :-) .
Thanks,
Jonathan
www.madlabs.info
>
>I want to implement a battery backup for a Stamp. Can I just hook both the
>DC voltage supply and the batteries together with a diode to protect the
>batteries? Eventually I will probably put a charger in the device and use
>NiCad batteries, but for now I want to be able to use either alkalines or
>NiCads that I charge away from the device. Any simple charging circuits that
>anyone has would be great too :-) .
>
>Thanks,
>
>Jonathan
>
>www.madlabs.info
diode diode
+battery --->|
o
|<----+DC supply
|
|
|
`
stamp Vin
I implemented two 1004 diodes in parallel, one diode
gets a 12v wall wort, the other a nine volt alkaline
battery. The joining diodes then have an electrolytic
cap to ground, and also go into a 7805.
Works great. The higher voltage from the transformer
eliminates any current flowing from the battery. To
check I put a 1 ohm resistor on the battery lead, and
sure enough, no voltage drop across it (1 ohm makes
for easy math conversion to ma).
Pull the transformer, and the battery conducts, no
hicups on the stamp or other devices I have running of
the 7805.
Regards, John.
--- Jonathan Peakall <jpeakall@m...> wrote:
> Hi All,
>
> I want to implement a battery backup for a Stamp.
> Can I just hook both the
> DC voltage supply and the batteries together with a
> diode to protect the
> batteries? Eventually I will probably put a charger
> in the device and use
> NiCad batteries, but for now I want to be able to
> use either alkalines or
> NiCads that I charge away from the device. Any
> simple charging circuits that
> anyone has would be great too :-) .
>
> Thanks,
>
> Jonathan
>
> www.madlabs.info
>
>
>
> To UNSUBSCRIBE, just send mail to:
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> Text in the Subject and Body of the message will be
> ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
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Original Message
From: "Tracy Allen" <tracy@e...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, February 21, 2003 11:23 AM
Subject: Re: [noparse][[/noparse]basicstamps] Battery Backup
> >Hi All,
> >
> >I want to implement a battery backup for a Stamp. Can I just hook both
the
> >DC voltage supply and the batteries together with a diode to protect the
> >batteries? Eventually I will probably put a charger in the device and use
> >NiCad batteries, but for now I want to be able to use either alkalines or
> >NiCads that I charge away from the device. Any simple charging circuits
that
> >anyone has would be great too :-) .
> >
> >Thanks,
> >
> >Jonathan
> >
> >www.madlabs.info
>
> diode diode
> +battery --->|
o
|<----+DC supply
> |
> |
> |
> `
stamp Vin
>
>
> To UNSUBSCRIBE, just send mail to:
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>
>
>