sos help, construct receiver circuit for optic fiber

Projects General Guidance
1

my project is to built optical receiver for detect optic fiber, and then convert to electrical signal for IoT to show data from optic fiber on the phone(blynk app)

ive read many from the web and book but i failed to build one.

my equipment use,

polymer optical fiber (POF)
photodiode:IF -D91
op amp LM741 to amplify the signal
light source wavelength: 850nm

current progress : i had already cladding the POF, to expose some area to detect my solution which is water in order to monitor the temperature of the water.

i hope u guys can help me to contruct the receiver circuit. many thanks !!!

2

yoda17:
my project is to built optical receiver for detect optic fiber, and then convert to electrical signal for IoT to show data from optic fiber on the phone(blynk app)

ive read many from the web and book but i failed to build one.

my equipment use,

polymer optical fiber
photodiode
op amp LM741 to amplify the signal

i hope u guys can help me to contruct the receiver circuit. many thanks !!!

You left out the key parameter, the wavelength of the signal on the cable.

Paul

3

And the data rate!

Mark

4

yoda17:
my project is to built optical receiver for detect optic fiber, and then convert to electrical signal for IoT to show data from optic fiber on the phone(blynk app)

ive read many from the web and book but i failed to build one.

my equipment use,

polymer optical fiber
photodiode
op amp LM741 to amplify the signal

i hope u guys can help me to contruct the receiver circuit. many thanks !!!

After waiting for a response from you, I question if you even have the proper tools to handle polymer optical fiber.

Paul

5

yoda17:
ive read many from the web and book but i failed to build one.

Did you try to build any ?

6

hey guys thank you for your feedback, my light source will be 850nm . And for data rate, im not sure hmmm

my equipment use,

polymer optical fiber (POF)
photodiode:IF -D91
op amp LM741 to amplify the signal
light source wavelength: 850nm

current progress : i had already cladding the POF, to expose some area to detect my solution which is water in order to monitor the temperature of the water.

thanks in advance T_T

7

also i tried to do coding for Arduino in order the output are shown on Blynk App ( the temperature and solution), but its not work T_T.

const int analogInPin = A1; // OUTPUT
const int solenoid = 13; // INPUT

int sensorValue = 0; // the value for the sensor
int thresh = 440;
int hysterisis = 1;

int max_val = 0, min_val = 1023, ave_val = 0, count_val = 0;
int count = 0;

void setup() {
pinMode(solenoid, OUTPUT);
// initialize serial communications at 9000 bps:
Serial.begin(9600);
digitalWrite(solenoid, LOW);
delay(1000);
pinMode(LED_BUILTIN, OUTPUT);
}

// read the analog in value:

void loop() {

//this for take the average of the sensor value
for (count = 0; count <= 16; count++){
sensorValue = analogRead(analogInPin);

if (sensorValue > max_val) max_val = sensorValue;
if (sensorValue < min_val) min_val = sensorValue;
count_val = count_val + sensorValue;
//Serial.print(count_val);
}
ave_val = count_val/16;
count_val = 0;

{
digitalWrite(LED_BUILTIN, HIGH); // turn the LED on (HIGH is the voltage level)
delay(500); // wait for a second
digitalWrite(LED_BUILTIN, LOW); // turn the LED off by making the voltage LOW
delay(500); // wait for a second
}

// to print the value of sensor
Serial.print("sensor = ");
Serial.print(sensorValue);
Serial.print("\t min_val = ");
Serial.print(min_val);
Serial.print("\t max_val = ");
Serial.print(max_val);
Serial.print("\t ave_val = ");
Serial.println(ave_val);

// for the analog-to-digital converter to settle
// after the last reading:
delay(100);
}

8

this is my optical receiver..... but seems not working.... T_T

simulate.png

9

yoda17:
this is my optical receiver..... but seems not working.... T_T

What you look for to tell you it is working?

Paul

10

The transimpedance amp probably won't work with an ancient 741 opamp on a 5volt supply.
You need a modern input and output rail2rail opamp for that.
Leo..

11

this is my optical receiver

The feedback resistor is probably too small. Try 100K. And, as mentioned above, the 741 op amp is terrible.

12

Use a comparator e.g. LM339

HFBR-14XX HFBR-24XX
Better still see page 11 here:
https://www.mouser.ca/datasheet/2/678/V02-0176EN_2018-03-13-1366199.pdf

13

Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html then look down to item #7 about how to post your code.
It will be formatted in a scrolling window that makes it easier to read.

Can you tell us your electronics, programming, Arduino, hardware experience?

Is this a school/college/university project?

Thanks.. Tom.. :slight_smile:

14

Use a comparator e.g. LM339

No, that would be inappropriate for a photodiode. A transimpedance amplifier is the standard approach, but with a modern op amp.

See Transimpedance Amplifier Design | DigiKey

15

81ec44a0e13ba598e45d76bc62b1e6e34814a700.jpg
81ec44a0e13ba598e45d76bc62b1e6e34814a700.jpg458×545 81.5 KB

Of course the particular diode used is important.

.

16

Diagram in post#14 is not a transimpedance circuit...

17

I wonder what D1 was for the circuit in #14. It is hard to believe it would ever work.

The comparator switches at about 2.5 V, and single Si photodiodes produce around 0.6 V.