Hi, I want know in general when to use power supply for arduino project? My project include an Arduino Uno R3, 3 gas sensors, 1 LCD 16x2, 1 buzzer and one GSM SIM 900a module. First, when i connect all this things ecept GSM sim 900a, all works are fine. Data displayed at LCD and serial monitor. But if I attached GSM sim 900a to sent SMS, only 1 sensors can use, which mean at microcontroller board, i only can attach 1 sensor and GSM Sim900a, the program run successfully. If a just attach another sensor without coding it. the previous sensor that attach cannot read the data. I also try to attach LCD 16x2 but still the data cannot read although the LCD screen is luminous. what is the problem actually?
Please read the forum guide in the sticky post. That will tell you what information we need to be able to help you, such as a schematic, your sketch/code, links to components.
I suspect that the GSM module, when not in standby mode, will draw all the available current from the Uno, possibly overloading it.
Hi,
Welcome to the forum.
Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html then look down to item #7 about how to post your code.
It will be formatted in a scrolling window that makes it easier to read.
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
You will need a separate supply, what gas sensor are you using?
Most gas sensors need a considerable amount of current to work, compared to the current that can be supplied through the Arduino.
The usual rule of thumb is to always provide a separate supply for sensors, and any output loads like servos, motors and arrays of LEDs.
The UNO can power the LCD but not the rest.
Thanks.. Tom... 