Go Down

Topic: Best rechargeable battery setup for Arduino BT ? (Read 2 times) previous topic - next topic

bill

#5
Aug 28, 2008, 11:45 pm Last Edit: Aug 28, 2008, 11:45 pm by bill Reason: 1
Related power question. My board has a 4 pin female header which reads/looks like:

  POWER
5V  Gnd  9V
x   x   x   x

I've read the admonitions about not using too high a voltage or reversing polarity--so just want to be 100% sure this means I can use, for instance, a 9V battery to power the whole board. I've looked at the schematic for the board, which shows a VIN but doesn't specify a voltage. So, a related question for my general education is am I missing something on the schematic? Should I be able to definitively answer this question for myself?

Thanks!  

aalex

It seems like recharging a battery is pretty straightforward. Just apply a DC voltage to the battery : plug +Vcc to Vcc, and GND to GND. We need a diode that makes sure the current only goes from the supply's +Vcc to the battery's +Vcc. That's it.

Now, I am currently looking at a 5V DC/DC converter to get 5V out of pretty much any voltage, it seems. With 2 AAA it should work. The Minty Boost from Lady Ada uses a LT1302. See http://www.ladyada.net/make/mintyboost/ and http://www.linear.com/pc/productDetail.jsp?navId=H0,C1,C1003,C1042,C1031,C1060,P1029

Though, this setup wouldn't last very long. It is a very nice IC for a small circuit that doesn't use much current, or is not intended to last so long. Also, note that a 7805 5V voltage regulator does heat up when used with a voltage of 7V or more. A DC/DC shouldn't create heat. It think it also doesn't burns Amperes-hours, which makes it a better solution than a 7805.

a

a

Alexandre Quessy

trialex

Quote
Related power question. My board has a 4 pin female header which reads/looks like:

  POWER
5V  Gnd  9V
x   x   x   x

I've read the admonitions about not using too high a voltage or reversing polarity--so just want to be 100% sure this means I can use, for instance, a 9V battery to power the whole board. I've looked at the schematic for the board, which shows a VIN but doesn't specify a voltage. So, a related question for my general education is am I missing something on the schematic? Should I be able to definitively answer this question for myself?

Thanks!  


Plug the 9V battery in via the external power connector, that way it is regulated by the 7805 down to the required 5V.

You can sort of answer the question for yourself - the first component after the plug is the 7805 regulator, so the arduino board's input voltage range is defined by the allowable voltage range of the 7805 - and you can find this in it's datasheet.

nigel_mck

The best choice for type of battery would bu lythium polymer. They last a really long time even when using multple motors. You can get them at a hobby shop. They cost about 25 canadian for the battery and charger. Hope that helps

warlip

Hi I am using a BT arduino just to send info to computer (with piezo contact mic)
Are 2AA also necesary or could i use something lighter like a lithium cell? I need to spare some
weight. thanx

Go Up