Sunday, January 10, 2010

Chomp! Chomp!...is your LilyPad project power hungry?

If you find your LilyPad project needs more power than the traditional AA battery, Leah recommends the following:

“The important spec for batteries is their mAh rating.  mAh stands for milli Amp hours & tells you how much energy is in each battery.  A typical LilyPad project requires approximately 30 milli Amps (or mA) continuously.  To estimate how long each battery will last for a LilyPad project divide the mAh rating by 30.




The tiny (rechargeable) LiPo that I recommend first (Polymer Lithium Ion Batteries PRT-00731) should run for about 3 hours (since it's rated for 100 mAh) http://www.sparkfun.com/commerce/product_info.php?products_id=731




The more powerful one I recommend for ~30 hours (1100 mAh) Polymer Lithium Ion Batteries PRT-00339 http://www.sparkfun.com/commerce/product_info.php?products_id=339




 


These can both be plugged into this LilyPad battery board (LilyPad LiPower DEV-08786) http://www.sparkfun.com/commerce/product_info.php?products_id=8786




To charge these batteries, you can use LiPoly Charger - Single Cell 3.7-7V Input PRT-00726 http://www.sparkfun.com/commerce/product_info.php?products_id=726

Additionally “I put a protective coating of hot glue around the points where the wires meet the battery & where the wires meet the plug connector.  With repeated bending & use the wires will break at their connection points without some sort of protection.”

There is also an important note about the placement of the power supply on Leah’s website:
“As you design, plan to keep your power supply and LilyPad main board close to each other. If they are too far apart, you are likely to have problems with your LilyPad resetting or just not working at all.”

For additional battery information see: important note about the power supply  at http://web.media.mit.edu/~leah/LilyPad/build/turn_signal_jacket.html

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