Changed the mosfet to an IRFIZ34EPBF and it works. WTF? Only thing changed was the type of mosfet. Tried multiples of the other and nothing.

Thanks for the help guys. Not sure where I'm going wrong. this is very frustrating, still have not got that circuit going properly.
So I went out and got some logic level mosfets, using Fairchild FDP7030BL n-channel mosfets now.

I hooked up the circuit and was getting PWM yesterday but now today when I hook it up I get just constant full brightness no pwm.

Have a 2k2 across the gate and source on the mosftet then the gate of mosfet attached to pwm pin, source of mosfet attached to ground and drain to - side of LEDs with an external +12v to + side of leds. Grounds are together.

Thanks Grumpy. Reason I thought it was slower is because on Adafruit store it says "In a pinch, you can even use it to program AVRs (its a bit slow but works!)"

I have a standalone arduino project which needs to communicate with a pc. Besides the FT232 breakout board from adafruit are there any other smaller boards that I can hook up to the standalone that will allow the transfer of serial data?

If not, I heard the FT232 breakout board is slow at programming, would it also be to slow to use as a communication board in a project? Only really need 9600 baud but would like more if possible.

Not much of an EE is he?

Looks that way eh..

Hooked it up exactly like the schematic and how yall have said. Still no luck. Going to try a different breadboard, seems I have no luck with breadboards.

Well, I must be looking over something small thats messing me up cause I have checked the wiring multiple times and have found nothing wrong. Even had an EE friend take a look and he said it looks right.

Its funny cause without the resistor from the FET gate to ground it works full brightness but no pwm.
When I have a resistor from the FET gate to ground no matter what size pwm works but with no brightness.

Hopefully one day I will get a hang of these dang circuits. These are supposed to be easy too, Im just wiring up LEDs for gosh sakes.

Excuse the crappy schematic, my first time using Fritzing.

My fault, I will give Magician suggestion a try.


~EDIT~

I hooked up the circuit as you wrote Magician and I get full brightness but no PWM.

By collector - gate MOSFET; you mean NPN collector to MOSFET gate correct?

Yes sir grumpy, I know they are not logic level thats why I'm running them off of the transistors. Yet even with the transistors switching +12v I can't get the full brightness with this setup and have PWM ability.

Magician:
If I put +12v to the transistor collector and then run the mosfet gate to the transistor collector wont it just get a solid +12v at the gate not allowing for pwm?

Afternoon guys,
So I went away from my 5940's which did not have the current capacity I needed and am currently using IRF510 mosfets to power my LEDs.
These are rated @ 5.6A and 100V.
I cannot seem to get PWM working through this setup while allowing full brightness of my LEDs. If I just digitalWrite them high and low they are full power, then when I try to analogWrite they will not pwm at all just stay on full with intermittent quick flash as if it went on/off extremely quickly.
I can only get the pwm to work when I put a resistor on the FET gate to common ground, but then the are only about 1/4 bright if not less. Have tried resistor values between 2.2k - 10k with no difference.

current setup:

Arduino > NPN Transistor gate (collector connected to external +12v, emitter connected to FET gate) > FET (mosfet source connected to common ground, Drain connected to LED negative side. LED positive side connected to external +12v.

very simple code just to make sure things work as they should.

Code:

int fadevalues[] = {0, 2, 6, 8, 11, 16, 23, 32, 45, 55, 64, 78, 90, 109, 128, 140, 162, 181, 200, 222, 255};
const int led1 = 10;
const int led2 = 11;

void setup()
{
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
}
void loop()
{
  for (int i=0;i<20;i++)
  {
  analogWrite(led1,i);
  analogWrite(led2,i);
  delay(100);
  }
  for (int i=20;i>0;i--)
  {
  analogWrite(led1,i);
  analogWrite(led2,i);
  delay(100);
  }
}

Solved the problem. I just changed the button input pins to high and made the sketch look for a low and it works. Thanks for the interrupt suggestion. I need to start using them more often, very useful.

Here is my new code using interrupts. It seemed to work rather well before I added the reset buttons. Now I am having the same problem I was originally having.

Code:

volatile unsigned int rpm = 0;
volatile unsigned int rpm1 = 0;
const int b0 = 10;
const int b1 = 12;
int bs0 = 0;
int bs1 = 0;
void setup()
{
        attachInterrupt(0, irq_1, FALLING);
        attachInterrupt(1, irq_2, FALLING);
        Serial.begin(9600);
}

void loop(){
bs0 = digitalRead(b0);
bs1 = digitalRead(b1);

if (bs0 == HIGH)
{
  rpm = 0;
}
if (bs1 == HIGH)
{
  rpm1 = 0;
}}

void irq_1(){
  rpm++;
  Serial.print(rpm, DEC);
  Serial.println(" S1 RPMS");
}
void irq_2(){
  rpm1++;
  Serial.print(rpm1, DEC);
  Serial.println(" S2 RPMS");
}

Maybe I need some debouncing code? It works fine with 1 button without debounce code so I don't see why I would need it now.

Is it possible to multiply the interrupts on the Arduino UNO? Or "spoof" more in code? I just started playing with them today due to feedback from another thread and was curious if I can add more to the uno? Sort of like multiplexing or hardwire other pins as interrupts?

I will try the interrupts way, as for the buttons I am using 10k from the "ground" pin from my button to the digital pin on my Arduino. So +5v -> button -> 10k ->Arduino

I have a setup with 2 hall effect sensors to read 2 shafts and different rpms. When my code was just setup for one everything worked fine, now that I have two for some reason its not working properly anymore.. It takes anywhere from 5-10 revolutions before it starts counting up. Before that it will just display 1, 1, 1, 1 etc then finally goto 2,3,etc... Also once its counting properly if I hit my button to reset the count it has the same issue. Horrible code issue? I am using 2.2k resistors across my power & signal pin on each sensor.

Code:

const int SENSOR = 12;
const int SENSOR1 = 10;
int rpm = 0;
int rpm1 = 0;
int lasthall = 0;
int lasthall1 = 0;
int hallstate = 0;
int hallstate1 = 0;
const int button = 8;
const int button1 = 9;
int buttonstate = 0;
int buttonstate1 = 0;
void setup()
{
pinMode(SENSOR, INPUT);
        pinMode(SENSOR1, INPUT);
        pinMode(button, INPUT);
        pinMode(button1, INPUT);
digitalWrite(SENSOR, HIGH);
        digitalWrite(SENSOR1, HIGH);
        Serial.begin(9600);
}

void loop()
{   
  hallstate = digitalRead(SENSOR);
  hallstate1 = digitalRead(SENSOR1);

if (hallstate != lasthall)
{
  if (hallstate == LOW)
  {
    rpm++;
    Serial.print(rpm, DEC);
    Serial.println(" RPMs S1");
  }
}
  lasthall = hallstate;
  buttonstate = digitalRead(button);
  if (buttonstate == HIGH)
  {
    rpm = 0;
  }
 
if (hallstate1 != lasthall1)
{
  if (hallstate1 == LOW)
  {
    rpm1++;
    Serial.print(rpm1, DEC);
    Serial.println(" RPMs S2");
  }
}
  lasthall1 = hallstate1;
   
  buttonstate1 = digitalRead(button1);
  if (buttonstate1 == HIGH)
  {
    rpm1 = 0;
  }
}

Each set of LEDs I would like to control independently pulls 800mA. For the LEDs in the picture there are 4 sets of 4 strips. Each set pulling 800mA with the total pulling 3.2A

I would like to fade them all from full on to almost off at the same time. I know I can go to something like a MOSFET which I will be doing for the final product but I would really like to get this working correctly (full brightness) with the components I have listed in the first post just to give me a better understanding of circuits.