Unable to supply power to multiple modules at the same time

Hello Everyone,

This is my first post here. Firstly, I am a total noob in regard to Arduino and its functionalities.
I am a software developer by profession, so I only have basic knowledge of the electronic components.

Currently, I am working on making an Autonomous Fingerprint Attendence System for my Office.
The idea is that, when an employee scans his finger on the fps(fingerprint scanner), the arduino will send data (havent decided on how I will achieve that yet) to a Java Application running on the Server PC, which in turn will update attendance for the respective employee. If the Server is down, the arduino is supposed to save the id of the employee and the time to the SD Card and send it again when the server is up.

So far, I have managed to program my arduino to identify, enroll, delete fingerprints. I have also added 2 leds (red for not identified and green for successfull), a buzzer, a pushbutton which helps in navigating into the main menu of the sketch. (Attendance is in loop, so when the button is pressed, it calls the function for Main Menu) I have managed to also set time to my RTC.

Following is the list of modules I have used in my project so far:
I am using arduino mega r3
GT511C3 (3.3 V supply)
DS1307 (5 V supply)
2 LED (Analog Pins, is very dim on Digital Pins)
1 Pushbutton (5 V supply)
1 Buzzer (Digital Pin)
1 4x4 Matrix Keypad (Digital Pin)

Now the problem I am facing is when I tried to connect my Ethernet Module, every other module malfunctions.

Ethernet Module I am using is ENC28J60

The fps led glows dim, both leds glow dim, keypad doesnt even take input sometimes.

So according to my assumption, the Ethernet Shield is taking up too much ampere than it is supposed to, that other modules are being affected.

Note: I tried the following link but failed.

The code compiled and uploaded but the html page is non-existant.

I want to know if my assumption is correct and if it is, what should i do to tackle it.
If not, please do help me understand it.

Thank You for reading through.
I would appreciate any advice on your behalf.
Thank you again in advance

You need a power supply that ethernet needs 180mA to transmit and 120mA just to be on. look up all the datasheets for all your components and add up the power requirements to figure out what you need... if you are using the arduino to power everything my guess is that your regulator will not last long.

Thank You very much for your response.

These are the ampere usages according to their respective datasheets (I measured the same for the LEDs and buzzer)

4x4 Matrix keypad - 30mA
GT511C3 (fps) - 130mA
ENC28J60 - 180mA
DS1307 - 1.5mA
LED (2x) - 40mA
Buzzer - 10mA

Total - 391.5mA ~= 400mA

I have given 1Amp 9V DC supply to my arduino from the wall.

Can you please help me out?
I still have to wire SD card and LCD modules, so I'm a bit worried here..

Thank You again in advance

you need a power supply... the onboard regulator will supply about 150-200mA tops (depending on your source voltage) and will heat up quite a bit.

You forgot the current needed for the Arduino also...

What's even worse is that the 3.3V supply is actually about 150mA limit... this might be even more of an issue for you.

Thank You again

I didnt know that the onboard regulator supplies only 150-200mA.
I just google on how to add an external power supply and I think I can figure it out by myself from here.