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Topic: 9v battery problem (Read 3326 times) previous topic - next topic

louish

hiii every one i have small big problem with my project . im using arduino uno and GPS Em406a and XBEE and LCD and want to power the  system with 9V battery but its not working properly the lcd keeps blinking and doesn't show text.
i tried several kinds of battery none of them worked , i tried to use 2 batteries one for the arduino  and another for lcd or the GPS with regulator 7805   and it also didn't work ...any help ???

PeterH

If you're talking about the common little PP3 9V batteries, they're a poor choice to power the Arduino because they are very expensive, have very little capacity and very little current capability - since the voltage is so high, the linear voltage regulator simply waste a lot of that power as heat and the end result is very inefficient, expensive and short-lived.

Having said that, the supply may not be causing your problem. Does your project work correctly when powered from the USB port? Perhaps you have a wiring/software problem.

louish

yes with the usb every thing works perfect .but whith 9v battery the lcd dont get enough power and the gps also cant supply signal to arduino with independent 9v battery ...

cmiyc


yes with the usb every thing works perfect .but whith 9v battery the lcd dont get enough power and the gps also cant supply signal to arduino with independent 9v battery ...

You're trying to draw more current than that tiny little 9V can provide.
Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

louish

so what is the solution its only 3 devices ///

cmiyc


so what is the solution its only 3 devices ///

The number of devices is irrelevant.  It is how much current the total draws.

You need a higher current power source.  Such as 6 AA batteries.
Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

louish

lets say you are right , can you explane to me why the arduino didn't get the GPS signal even though its supplied from a defferent battery with regulator circuit ?  the same thing happened when i tried to supply voltage to the lcd alone . 

PeterH


lets say you are right , can you explane to me why the arduino didn't get the GPS signal even though its supplied from a defferent battery with regulator circuit ?  the same thing happened when i tried to supply voltage to the lcd alone .   


Without more information about the circuit and your sketch it's hard to say, but since the problems go away when you connect a decent power supply it seems reasonable to suppose the power supply is what is causing your problem. I suggest you replace those expensive and ineffective PP3s with some AA or AAA batteries, and see if that cures your problem.

louish

okk i will try it but tell me which batteries are better aa or aaa and how many battries you think arduino+ lcd+XBee+GPS em406a needs ?

PeterH

AA are bigger capacity and bigger size than AAA. If size is a problem you may be constrained to use AAA, but if you have space for AA then they will give you more current for longer. It would be sensible to look for rechargeable batteries if this is for long term use.

Assuming you are aiming to connect via the external DC jack connector you want to aim for about 7V supply. Depending on the type of battery you use you are likely to get between 1.2 - 1.5V per cell. Six NiCds will give you 7.2V which is about right. Five NiMhs will give you about 7.5V which is also about right. You will probably find six-cell battery holders easier to find and that will give you about the right sort of voltage with any of the normal alkaline or rechargeable batteries you'll get in AA or AAA format.

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