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Mike15
05-06-2006, 01:37 PM
I am building a rocket payload that consists of an eeprom, RTC, two ADC's, and an accelrometer. Because of the weight I need to find a small light weight battery.
I don't know alot about the power supply end of things so bear with me. If I add up the supply currents I have 13 mA. I have the power connected to Vin to internally regulate the voltage to 5V.
I have already built a prototype using a 9V battery but this weighs almost 2oz.
Does anyone have a suggestion on a sutable light weight battery?

MCL9449
05-06-2006, 07:56 PM
LiPo (lithium polymer). They are a bit expensive, but very light. They come in various capacities and in multiples of 3.7v.

allanlane5
05-06-2006, 08:18 PM
I believe there's an "N" cell. And you can stack 'coin' cells.

Mike15
05-07-2006, 07:33 AM
Here is the schematic.

The two ports are PC screw terminals so I can add with ease. In the future I will probably use a MAX186 instead of the 187.

And if I understand SPI correctly I should be able to connect the SCK of each IC to 1 pin and the SI SO pins of each IC to 1 pin. I just need to connect each IC's CS to seperate pins. Right?


Post Edited (Mike15) : 5/7/2006 12:05:03 PM GMT

Bruce Bates
05-07-2006, 11:20 AM
Mike -

Selecting the proper IC via CS is generally fine, as is using common CLK and DATA lines.

Regards,

Bruce Bates

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Chris Savage
05-07-2006, 01:09 PM
Mike,

Perhaps I am missing something in your schematic, but you mentioned an RTC, but you don't seem to have one listed in that schematic. You also have a crystal connected to the Digital Thermostat in the schematic.

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Chris Savage
Parallax Tech Support
csavage@parallax.com (mailto:csavage@parallax.com)

Mike15
05-07-2006, 06:55 PM
The DS1602 is a RTC from Dallas Semiconductor.

Chris Savage
05-08-2006, 01:29 AM
Sorry, I re-checked your schematic and last night my eyes transposed the 02 to 20...I thought you had the DS1620.

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Chris Savage
Parallax Tech Support
csavage@parallax.com (mailto:csavage@parallax.com)

Mike15
05-09-2006, 05:57 AM
I found a 12V 23A N cell that seems to work fine. Thanks for the help. In the next couple of days I'll post the whole project.

Bruce Bates
05-09-2006, 07:40 AM
Mike -

Just a friendly reminder. If/when you post your completed project, please do so in the "Projects" Section of this forum, as that's where folks will go to look for it. Thanks!

Regards,

Bruce Bates

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Post Edited (Bruce Bates) : 5/9/2006 12:50:23 AM GMT