Please help ....How to connect to andriod

Hello everyone !! this is my first time to use a forum !!! I am trying to emulate the Arduino process by communicating to the Andriod. my project is very simple I want to switch an external LED ON/OFF from Android without using the Arduino !! as the Arduino board is complicated and big for my device and what all I want is simple Switch ON/OFF for external LED. is that possible ???? like How does the Arduino electrical components work that it force the phone to send to it signals ??????? s
any difference of Signals I can get is fine coz then I can amplify or play with it to distinguish ON/OFF .

Welcome on the Arduino forum,
please google "android +site:arduino.cc" and you will get many relevant hits

thank you for replaying :slight_smile:

However I don't want to use an Arduino board to connect to my Android, all what I want is to use the same signals the Aurdino get when Receiving Data (RX) and use it to switch ON an LED . So basically I Want to switch ON/OFF an LED without Aurdino , I will still need to make Pull up and Pull down resistors so I can recieve signals from the Andriod without the use of Aurdino for now I have created the application It is sending signals to the Aurdino bcz I can see the RX blinks when i press ON from the App . so I want to receive the same signal as RX without Arduino and use it to Switch On/OFF an LED .... is that possible ?

my project is very simple I want to switch an external LED ON/OFF from Android

Don't know your knowledge level (SW or EE), but I consider that not a simple project as Android has no external ports you can easily connect a led (or whatever) to.

What device is running Android?
Can you post a schematic of what you have in mind?

If you connect a LED (in the right way) in series with a 220 ohm resistor to a 5V power source it will be ON, otherwise it will be off.

Note: If you do not place a resistor in series, you get a short flash and a broken led.

Hello !!

Well My Android device is SAMSUNG GALAXY S4 .. what I exactly have in mind is to Switch On/OFF external LED without the use of Arduino but I don't know how to achieve this ..so I was thinking to Use pull up and pull down to imitate the D+ and D-of the Aurdino .. when I did this I received signals on oscilloscope for 2 seconds once I plugged the OTG-USB port to the phone and then I don't receive anything even when I press the switch buttons of the App .. Thus, I wanted away to know what happened that I received this 2 seconds signals After I plugged the phone so I use the same concept to Send the signal of ON/OFF

when I press the switch buttons of the App

what is the App?
Sorry, but I try to get a complete understanding of your question.