the voltage

Projects General Guidance
1

Hi all,

I'm fairly new in arduino world, and i start to do my project, but i have a problem with power source, i don't know how many volt my project need, because first i tried with two AA rechargeable batteries and that didn't work, then i add two more AA rechargeable batteries also it didn't work.

My project components:

  • Arduino UNO
  • SIM 900 GSM/GPRS shield
  • LCD
  • Two led
  • Lm35
  • Buzzer

All these components work well when it bulged with laptop cable, but the shield didn't send any message, and when i add a 9v battery to the project the shield work well and start to send the messages, so i understand that the laptop power source is not enough for the shield it need extra power to work.

So what kind of batteries i need to work every thing well and how many volt i need for my project ?

thank you

2

The arduino Uno itself needs 7~12v (see the product page https://www.arduino.cc/en/Main/ArduinoBoardUno ) to get 5v on Vcc. Sadly, they cheaped out on the regulator in the Uno - had they used a better regulator, it could have worked off 6v, so you could run it off 4 alkaline AA cells...

As it is, you would need 5 AA batteries (6 if using rechargables). Or a 2S LiPo/LiIon pack.

Those common rectangular 9v batteries are not suitable - they cannot supply the high peak current required by the SIM900 (or most other projects).