SD logger and cell phone module

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tinkeringtech
 
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SD logger and cell phone module

Post by tinkeringtech »

I want to use the adafruit SD logger shield along with the sparkfun cellular shield. My concern is that there will be a conflict in pin use. According to the schematics http://www.sparkfun.com/datasheets/DevT ... ld-v12.pdf and http://www.ladyada.net/make/logshield/design.html seems like there is no conflict, but not sure. I am also concerned about power consumption. Can I put the logger shield on top of the cell shield and not have to worry about power? :shock: Thanks for any help.

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Re: SD logger and cell phone module

Post by adafruit_support_bill »

I don't have any firsthand knowledge of the Sparkfun shield, but there do not appear to be any pin conflicts in the schematic. The power question depends on a couple of things:
What are the power requirements of the cellular shield?
How are you powering the Arduino?

The logger will need on the order of 60-80mA when writing to the card. The capacity of the Arduino regulator depends mostly on the input voltage. With a 12v supply, it will be running hot at 200mA. With a 7v supply, the regulator can handle much more.

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tinkeringtech
 
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Re: SD logger and cell phone module

Post by tinkeringtech »

What are the power requirements of the cellular shield?
How are you powering the Arduino?
How is the SD logger powered? via the UNO 5V pin? Sorry, still learning and want to be sure I'm reading the drawings correctly before trying anything.

According to the schemetic, does it look like the cellular module is powered via the VIN? I have read that the cell module can draw about 400mA for a text message, would a 5V 2A external power supply work? Is there a chance of smoke if there is a pin conflict? :? Wish Ada made a cell shield, can bet the documentation will be alot better :D Thanks for your help.

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adafruit_support_bill
 
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Re: SD logger and cell phone module

Post by adafruit_support_bill »

The logger shield is powered via the 5v pin. If you have an external 5v regulated supply, you can bypass the UNO regulator and go direct to the 5v pin. The 5v/2A supply you suggest should work fine.
Is there a chance of smoke if there is a pin conflict?
No - not with logic pins.
However, do use care when wiring your power supply. Double check polarity before connecting anything.

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