Is there any way an Arduino Uno can control a DC motor without a Transitor, Diode, or Motor Shield ? I made a circuit by connecting the two wires to 5V and GND, but how would I control it?
Current is the issue. Are you working through the Starter Kit book? There are projects that will lead you through the setup and code. I am reading Arduino Robotics, a good book that I got for cheap at Amazon. The first robot project details how to modify a servo for continuous rotation. There is also a discussion on motor types. The author prefers using servos because they have gear reduction and are more easily controlled through the Arduino with the use of the Servo.h library. There are many other books available for reference too. I haven't gotten that far yet, so I cannot give you a specific answer or example.
You should not try to power a motor from the Arduino 5V output. It is not designed for that and you can damage the Arduino. Use a separate motor power supply (and control circuit), being sure to connect the two grounds together.
I do use a external battery supply with 6 batteries. I also do connect to GND. The DC motor DOES RUN when I connect the power and GND. I cannot control the speed or direction, though. Although the book, I just bought it, gonna read it.
The answer is NO, not possible if you are using electronics. there are transistors inside all micro controllers and microprocessors.
besides, it takes only one transistor and one resistor. it is does not get simpler than that.
read about PWM
think of it another way, you have a mind and a hand. can you move a book without using your hand ?
the arduino is the controller; the mind if you will. The rest of the playground is the other parts we need to add and combine to make things that do the work we want. the transistor is the first step out of logic signals to doing something.
Level_100: I do use a external battery supply with 6 batteries. I also do connect to GND.
That makes no sense in the light of your original post:
I made a circuit by connecting the two wires to 5V and GND
It does I think - the 6 cell pack is going to Vin...
However this isn't likely to be satisfactory either.
Use a separate supply for the motor, not shared in any way with the Arduino or other sensitive electronics.
Just make the grounds common at the transistor (emitter or source, depending if BJT or MOSFET).
Don't forget about a free-wheeling diode in any circuit switching an inductive load (coils, relays, electromagnets, motors are all inductive loads).
You're probably right Mark- I took "external" to mean over and above the Arduino power, ie supplying the motor direct. But it does read more like he means external supply into Arduino, and power to motor from Arduino. As you say, that's folly.