Having trouble with Tutorial 5. Please help.

Hey, I'm no expert, but here's two things I noticed.

1. Your code sets digital pin 1 as OUTPUT but your wire is connected elsewhere according to your picture.

2. You need to connect the ground from the arduino to the ground from the battery.

Hope this helps. Otherwise I see no errors in your code.

Thank you. I fixed both of those. Unfortunately I am still getting no output from my arduino Have I hooked the ground to ground correctly, or could that still be the problem?

int motorPin = 9;
void setup()
{
  pinMode (motorPin, OUTPUT);
}

void loop()
{
  for (int i=0; i<=255; i++)
  {
    analogWrite(motorPin, i);
    delay(10);
  }
 
  delay(500);
 
  for (int i=255; i>0; i--)
  {
    analogWrite(motorPin, i);
    delay(10);
  }
delay(500);
}

Hi.  Assuming that you Arduino is working correctly, you have some steps you should take.  one, remove the input from the Arduino at the Base resistor.  Take that wire and place it at the +5v header pin  The Motor should turn on and run at its max speed, with the Arduino powered up via the USB or the Power Plug.  If this is OK then the problem is still at the output pin.  If this is NOT OK, then the problem is the base resistor (too large) or the wiring to the transistor, or the trasistor its self.  I would look at the datasheet to insure that you have wired it correctly.  Good Luck.

Dave M.

I took the wire, put it in the 5v pin and it still did not turn on. But I measured with a multimeter and there was current going through from the 5v pin to the base. When I measure from the 5v pin to the motor, i reads -5 volts, but when i measure from motor to the base of the arduino i get 9 volts. Is this a problem with how by bases are set up? How is it possible to get two different voltage readings going through the same circuit? Also, I switched the resistor with a 270 Ohms and it made no difference.

OK, that helps some.  Now we need to see each piece.  Connect just the motor to the battery.  Does it work OK?  If OK, You need to insure that the circuit is wired correctly.  I have made a schematic for you just to make sure,  I have included a Diode and Cap that goes between the Motor terminals, but for testing they can be momited for now.  But should be included for correct circuit operation (removing noise made by motor).  Make sure the Ardunio GND and Battery GND and Emitter are all connected together.  On the PWM input, try the 5V to the resistor.  Motor should spin.  If not, replace the transistor.  If you have a meter, you can check to see if the transistor is OK.  Check all connections are GOOD.  nothing like thinking you have a bad part, and the wire turns out to be to problem or the solder joint.  I have used a 2N2222A2N2222A transistor, but any NPN that can handle the Current flow for the motor will work.  When looking at the data sheet.  MAKE sure you understand the orientation of the drawing when selection of the Emitter, Base and Colletor.  TO-92 parts have been installed countless times reversed because of the diagram.  Once you have the circuit working with just the 5V, Battery and GND.  Connect to the Arduino PWM line you have selected in the program.  All should be good at this point.  Good Luck.

I would like to add that I'd recommend you to use solid copper wire, it looks stranded in your picture. Or you could neatly twist and solder the wire ends for better connection. I had similar problems when I just started and stranded wire was all I have. Additionaly, using black wire for ground and other colors for signals makes it easier to troubleshoot and understand when you take a picture.

Please let us know how it goes.

@dmaruska: I'd appreciate it if you let me know what app you used to create that neat schematic, thanks.

An easy source for solid core wire is a chunk of cat5 or telephone cable - lots of different colours in there too. you might find some free cutoff chunks or old cables at a local computer store, for example.

I have a license of OrCAD that I do schematics with.  It's a nice tool, could be made better, but I have been driving it since it went from DOS to Windows.  I cut and paste in to paint and post.

Regards,

Dave M.

Thanks.

This is TROY!       Actually it is NI Multisim 11.0 Breadboard view.

Click on image for a much better resolution view.

I believe that my transistor is the failure point. I set up a very simple circuit with the transistor and an LED. After hooking this up, the LED did not light up. But if I connected the far left pin and middle pin of the transistor, the LED did light up. Is this a confirmation that the transistor is dead?

What is the number on the transistor you are using?

What is the number on the transistor you are using?

2N

4401

711

It’s a 2N4401 made in 1987, 1997, or 2007, 11th week

You can get a data sheet from www.alldatasheet.com for free.

Maybe one of the transistor super-experts can comment, but to me nothing stands out as being wrong in the specs or in your picture... so yeah I would try another transistor.

Ok, I will get another one and test it out. Thank you guys sooo much, you have been  very patient and undetstanding.

You're very welcome. Thankfully transistors are super cheap, you can even find them in almost any old electronics

ps, did you see this tutorial from oomlout?  I found it nice and clear and easy to follow. Circuit 3 is the variable speed motor one.

http://www.oomlout.com/a/products/ardx/