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Topic: sos help, construct receiver circuit for optic fiber (Read 460 times) previous topic - next topic

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 (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 !!!

Paul_KD7HB

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

holmes4


Paul_KD7HB

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

srnet

ive read many from the web and book but i failed to build one.
Did you try to build any ?
$50SAT is now Silent (but probably still running)
http://www.50dollarsat.info/
http://www.loratracker.uk/

yoda17

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

yoda17

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);
}

yoda17

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

Paul_KD7HB

this is my optical receiver..... but seems not working.... T_T
What you look for to tell you it is working?

Paul

Wawa

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..

jremington

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

larryd

No technical PMs.
The last thing you did is where you should start looking.

TomGeorge

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.. :)

Everything runs on smoke, let the smoke out, it stops running....

jremington

Quote
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 https://www.digikey.com/en/articles/techzone/2017/jun/how-to-design-stable-transimpedance-amplifiers-automotive-medical-systems

larryd



Of course the particular diode used is important.






.
No technical PMs.
The last thing you did is where you should start looking.

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