Weird Problem

Sounds like the transistor is the one thing left to check.

Try hooking up the transistor directly (edit: through a resistor!) to 5v on the control pin where the arduino would normally be controlling it. ie, try the whole thing without the arduino control first. Use the arduino just for power and ground.

Check that the transistor is the right type (NPN vs PNP) and that it is not in there backwards.

I know I had a similar issue when I was trying that tutorial a few months ago, but I forget what exactly I did to clear it up.

Cheers,

-Nico

test that code on another transistor and 1k in base  collector in negitive wire of the motor the emitter pin to gnd if it npn if it pnp positive current side test both if u have npn and pnp

exactly as Pablo said, and you MUST use a resistor from the Arduino pin to the Base, otherwise you have a direct current path from your arduino pin to a power rail, and this can easily destroy that port.

the Emitter-Base junction is the same as a Diode.

Here's the Oomlout tutorial, which provides a pretty clear schematic too. Assuming you're using a different tutorial, this might help by giving another angle on it.

http://www.oomlout.com/oom.php/products/ardx/circ-03

Cheers,

-Nico

if that 2.2k miht be the problem i was told 1k resistor  if ur using a 2.2k switch it to 1 k 1/2 watt and i think 1/4 watt be the same

i getting in to arduinos myself so far i know is the 1k resistor is widly used for controlling a transistor

Message was edited by: Pablo Garcia

quite funny really, I was using the 2N2222A2N2222A yesterday to drive 12v relays with a 5v signal from a TTL And gate

I used a 4k7 to feed the base and the base also had a 20k pull-down resistor (so nothing bad happens if I pull the AND chip).

I`m thinking that IF the transistor is ok, could the Back EMF protection diode be forward biased?

4k7 ?

YT2095 u have a schem of that project ?

Message was edited by: Pablo Garcia

No, I haven`t drawn one yet, but I can do if you like, I`ll probably post it in my Blog when I do a write-up for my latest Robot build, it`s very rare that I actually write any of my circuits down to be honest.

also 4k7 is just the same as 4.7k (4700 ohms), I just write it that way out of habit

it kinda through me off a bit like wtf lol but yea a 4.7k idk i havnt seen any schem other then 1k so if ur having a similer problem try using a 1k seen lot of schem's with 1k if u have the time make a schem in cad soft eagle helps when ur not to sure it allows u to see where u wired it in i fried a L298HN it helps when u build it or draw it making ur own datasheet

my circuit works perfectly with the 4k7, I`v just drawn it out for you here:

it`s not perfect and may need magnifying a little? but it works great (I have a board with 8 of these on that have been working well for nearly a decade), so this same CCT will also be suitable for the Original post, just swap out the Relay coil for your motor, and the AND gate should be the arduino pin.

I`m using 12v on mine as that`s what the relays needed, but 5V will work too