how to increase p-p amplitude in arduino 3rd pin

int32_t frequency = 100;

#define PIN 3

void setup(){
    pinMode(PIN,OUTPUT);
    int DUTY = 10;
    InitTimersSafe();                    // won't touch timer0
    SetPinFrequencySafe(PIN,frequency);  // again, not timer0
    pwmWrite(PIN, DUTY * 256 / 100);
    // Sensor(s)
    pinMode(A0,INPUT);
    // for debugging
    Serial.begin(9600);

i used this code to generate 100hz and 10% duty cycle, the output p-p amplitude is 528mv according to my specification i need 1.5volt can any one have any suggestions.

i used op-amp 741 but instead of increase in amplitude…it starts decreasing in amplitude :frowning:

i have attached my specification for your valuable suggestions

IRL 81A, Lead (Pb) Free Product - RoHS Compliant.pdf (179 KB)

i used this code to generate 100hz and 10% duty cycle, the output p-p amplitude is 528mv

Needs more shift-key and punctuation.

How did you measure the 528 mV ?

As AWOL says, you need to make your sentences more correctly.
This is not texting with lots of guessing what you are saying.
What is your goal?
Your specifications seems to be a bit less than your goal.

Have you got a resistor in line with that LED? You need one because you are killing your Arduino without.

i used this code

No, you didn't.

Sorry for my English

I used pwm pin 3 to give pulse signal to my IRLED IRL81A

According to specification in datasheet i have to give 2 volt input to get maximum intensity. So that i can couple through decladed and streched fiberoptic to photodarlington. The output is very low when i use this program (i.e)540mv, guide me how to pullup the input volt to IRLED through arduino

I used DSO to measure milli volt.

Grumpy_Mike:
Have you got a resistor in line with that LED? You need one because you are killing your Arduino without.

Oh No! i never used it, because the output from pwd pin 3 is of ~500mv I thought it won't affect LED but i never thought of arduino is suffering. shall I use 10k ohm ? or what range i need to use?

According to specification in datasheet i have to give 2 volt input to get maximum intensity

The Arduino gives it a 5V pulse.

The output is very low when i use this program

The program has no effect whatsoever on the output voltage.

guide me how to pullup the input volt to IRLED through arduino

Read reply #3

. shall I use 10k ohm ?

No use 100R.

Grumpy_Mike:
The Arduino gives it a 5V pulse.

From PWM pin 3 in arduino, I measured using multimeter as well as oscilloscope it shows only .5volt not 5 volt brother.

From PWM pin 3 in arduino, I measured using multimeter as well as oscilloscope it shows only .5volt not 5 volt brother.

I keep telling you this is because you shorted out that pin by connecting an LED directly across it without a resistor. Yes it reads low, remove the sodding LED and it will read normally.
I am not your brother.

as you said i used 100R resistor before LED i measured the voltage across the LED it shows 500mv

is this circuit diagram is correct according to my specification IRL81A

Do i need Lock in amplifier for detecting very low change in voltage in PD

I looked at your Oscope wave form, but I could not see any voltage levels marked.

A PWM signal will read one thing on an voltmeter, and quite a bit different on an Oscope.

What is this P-P amplitude you refer to ? Is that peak to peak?

akmsr:
as you said i used 100R resistor before LED i measured the voltage across the LED it shows 500mv

It is the voltage across the resistor and led combined that will give you five volts.
You will not get 2.5V across it until you put 1A down the led, something you can not get from the pin of an Arduino.

The fact that you only have 0.5V across it suggests to me you have it wired the wrong way round.

I suggest you go back and reread the specification.
As Mike has said, you need to drive it with 1A to get it to 2Volts.
Even then, you need to average 180mw, its rated level,
and the pulse width on can't be more than 100us.
This means you can only pulse it once to 2V once for 100us
at a repeat rate of 1.33 seconds.
This all assumes you can drive 1 ampere into it.
As Mike has said, you don't have that much current from a
Arduino output.
What do you want to do from here and what is it that you're
trying to do?
Dwight

Is the LED lighting?
Is it pretty bright?
What is the problem?

The circuit diagram from post#11 shows the IR LED pointing at the receiver (not grounded).
The diagram also shows the photo darlington connected only to 5volt (or is it A0).
Maybe we have to SEE how it is actually wired up.
Leo..

shall i use this resistor.

source is 5volt (PWM pin3 in arduino … but what i measured is 0.5volt from pin 3 to GND pin)
forward voltage 5 volt
forward current 100mA

Untitled.jpg

NO, put a resistor of 200 ohms to 1000 ohms in series with the led.

Look - you should ask a pin to produce no more than 40mA and preferably less than that in the 20 to 30mA range.

You have repeatedly been told this, why do you persist in ignoring what everyone is telling you.