Powering a Mini4wd motor with arduino

Other Hardware Motors, Mechanics, Power and CNC
1

Hey Guys! Newbye here :slight_smile: I'm approaching Arduino from just a few days and i got an idea that i can't realize. I found in my component's bin an old mini 4wd motor that i'd like to power up to make him move things
( More specs about my project : i'm building a circuit that can close a windows when umidity is upper than a preset value.
Of course i'm experimenting this in a small-scale prototype, )
But i don't know how to interface the mini4wd Motor.
It's a 3V DC brushes motor(usually sourced by batteries) ,but it needs an high current to work properly ( about 1A ).
In the arduino specs i read that every digital pin can source/sink a maximum 40mA current. So i guess i need to use a transistor controlled by the arduino powers source (5v or 3,3 v ) to let an high current reach him ( sourced by a battery pack for example) but i'm not really good with transistor and i don't know how to wire it up.( got BC337 transistors)

So my questions are:
Is my reasoning right ? or can i source my motor directly with the arduino 3,3 V?
How should i wire the transistor up?

2

A BC337 (NPN transistor) is rated for only 500ma. With just a single transistor you will only be able to drive the motor in one direction. You need an H bridge to drive it bi-directionally.

Good tutorial for transistors: Transistor Circuits | Electronics Club

Inexpensive H-bridge (L293): http://letsmakerobots.com/node/2074

3

Chagrin:
A BC337 (NPN transistor) is rated for only 500ma.

Thank you for the advice about the transistor, didn't know that before. I'll search for another type of transistor
but the motor just moves in one way ( ok sounds stupid , it closes the "window" but it can't open it back) but i'm just starting over. Do i need the H bridge same way?

4

If you're only feeding the motor current in one direction (you don't want to be able to reverse the polarity) you do not need an H bridge.

A TIP120 would be a popular transistor of the size you need. Do a web search for TIP120 and you'll find plenty of tutorials.

5

You will have the fewest problems if you use a motor driver board optimized for low-voltage toy motors.
This inexpensive example will handle two motors and provide bidirectional control: SparkFun Motor Driver - Dual TB6612FNG (1A) - ROB-14451 - SparkFun Electronics

If you just want to learn about current amplification and junction transistor behavior, then go that way and build your own. Or use a logic-level MOSFET transistor - lots of tutorials available for either.

6

Thank you so much guys!Now ordering all the stuffs i need and then i'll try every way you suggested me :slight_smile: