Re: Data logger
- I'll finish testing it and post the results with construction
details. Probably about two weeks if all goes well.
--- In Electronics_101@y..., "Vijay Raju" <vijayxraju@s...> wrote:
> I need it around the end of October.
> The average woman prefers beauty over brains because the average
> see better than he can think.
> -----Original Message-----
> From: manifold [mailto:manifold_1@y...]
> Sent: Thursday, September 26, 2002 10:26 AM
> To: Electronics_101@y...
> Subject: [Electronics_101] Re: Data logger
> I did just finish a design based on the Maxim MAX713 that is
> to charge NiMH batteries from a car battery. The idea is that I
> needed something to charge my batteries when I go camping. How soon
> do you need it?
> --- In Electronics_101@y..., "Vijay Raju" <vijayxraju@s...> wrote:
> > Hi,
> > Thank u all for the valuable suggestions. Maybe I should
> > the "data logger". The unit has a GPS module and a an LCD, These
> are the
> > two power hungry devices. These two alone under full operation
> > about 150 - 165 mA at 5V. The rest of the components including a
> > microcontroller, memory and a UART draw about 20 mA. I have tried
> > level best to reduce the power consumption but this is as far as
> > get. I want to carry this unit on treks, cycling trips etc. A
> friend is
> > planning to go on a kayaking expedition in a few days and he
> > to take it along too. Basically I would like this unit to work
> without a
> > recharge or change of batteries for about an 8 - 10 hour period.
> > I would also like to know if it is possible to charge a lead-acid
> or a
> > Ni-MH battery using the battery in a car because finding
> electricity in
> > rural India (my friend intends to spend nights in villages during
> > expedition) is not an easy proposition.
> > The average woman prefers beauty over brains because the average
> man can
> > see better than he can think.
> > -Vijay
> > -----Original Message-----
> > From: CTC [mailto:ctc@2...]
> > Sent: Wednesday, September 25, 2002 8:20 PM
> > To: Electronics_101@y...
> > Subject: [Electronics_101] Data logger
> > Vijay Raju wrote:
> > "I have designed a small data logger which uses about 200mA @ 5V"
> > This is a rather heavy load for a battery to handle. I'd use a
> small 6
> > Volt
> > lead-acid gel-cell (stacking two or three silicon diodes in it's
> > line
> > to drop the voltage). Any other sort of battery would too
> > dead,
> > and if you wish to operate this devise for more than a couple of
> > you'll need to go to a larger battery. Would it be feasable to
> > the
> > device to reduce it's current requirements?
> > A fully charged 6 volt lead acid battery produces 6.9 VDC, thus
> > silicon diodes in series with it's output would reduce the
> > approximately 1.8 VDC resulting in an output of 5.1 VDC. If the
> > can
> > handle a slightly higher applied voltage, on the order of 5.7 VDC
> > two
> > diodes should be sufficient to reduce the voltage, and will
> > circuit for a slightly longer time.
> > I did a quick google search on gel-cells to get an idea of how
> > would
> > sustain your circuit. The smallest I could find has this
> > 6 volt, 0.5 AH SLA
> > Discharge Current @ 20 hr. rate - 25 mA, Length - 2.24 in. or 57
> > Width -
> > 0.55 in. or 14 mm, Height - 1.97 in. or 50 mm, Height Over
> Terminal -
> > 1.97
> > in. or 50 mm, Approx. Weight - 0.2 lbs., Standard Terminals
> > This battery, while quite small, would only sustain your device
> > approximately two hours.
> > Here's one that would power the device for over 20 hours, but it's
> > considerably larger.
> > 6 volt, 4.5 AH SLA
> > Discharge Current @ 20 hr. rate - 225 mA, Length - 2.76 in. or 70
> > Width - 1.89 in. or 48 mm, Height - 4.02 in. or 102 mm, Height
> > Terminal - 4.26 in. or 108 mm, Approx. Weight - 1.95 lbs.,
> > Terminals
> > By tolerating additional expense, and size, you could extend the
> > operating
> > time to as much as 180 hours, but this would require a 36 AH
> > Hour)
> > battery weighing in at about 14 pounds and requiring 145 cubic
> > (or
> > 2,379 cubic centimeters) of space.
> > It becomes apparant that the size of your device will be limited
> > desired running time, but you didn't specify that parameter. I
> > this
> > gives you some assistance at any rate.
> > Don
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--- In Electronics_101@yahoogroups.com, Howard Hansen <hrhan@...> wrote:
> Norm, near the beginning of the book the author states all the examples
> in the book the 1 bit SPI mode.
> > --- In Electronics_101@yahoogroups.com
> > <mailto:Electronics_101%40yahoogroups.com>, Howard Hansen <hrhan@>
> > wrote:
> > > I still recommend you purchase a copy of "SD card projects using the
> > PIC MIcrocontroller". >
> > > Howard
> > Howard do you remember if the book includes SD 4 bit bus mode or only
> > the more common 1 bit SPI mode?
> > Norm