Good day. I want to connect my I2C LCD (16x2) and KY008 laser, however, it draws 50 mA and 30 mA respectively. The manual said, maximum per I/O pin is 40mA and the recommended is 20mA. Will it damage the pins? Thank you for your help.
Hi,
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Your I/O pins will not be supplying the current to drive the LCD and Laser.
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
Tom... 
But you wont be powering it from an I/O pin, so that's OK.
een LCD zou met een arduino moeten werken. Alleen de laser maar dat kan met een relay zoals Lennard zei.
Alleen ligt het er aan hoe je je laser wilt gebruiken. Code kan handig zijn.
Aartjan...
I want to use the laser in a 'if' statement. Yeah. Maybe I should use a separate power supply but connect the pin Arduino uno.
OK, now the said laser has a 91 Ohm resistor on the assembly.
If we add the effective 35 Ohm internal resistance of an ATmega328 and figure on about 2 V for the diode drop, then we expect it to draw 24 mA which is pretty much what I have measured and quite safe for the Arduino pin to drive directly.
The I2C backpack and LCD display is powered by the 5 V supply, not an Arduino pin, so that is no problem. Do not try to power the Arduino via "Vin" or the "barrel jack"; that would be asking for trouble. 
hopen dat het hiermee opgelost is.
en succes met je project.
Aartjan...