How to connect SMA cable from photodiode to Arduino and read voltage

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1

Hi! I would like to make laser intensity light measurement using a photodiode with bias module. Output is SMA connector which transfers the photocurrent. The question is how to connect this output to Arduino so I could read voltage from it (so I could recalculate it to power and then to intensity).

I did some research and two most common answers were:

  1. Use SMA pigtail.
  2. Use SMA male/male coupler and then female flange bulk head.

But I am not sure how to really do it. I read that I should connect core to the load resistor and ground it and cladding connect to ground. But I am not sure how to perform this via Arduino Uno board.

Thank you for answers.

2

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

SMA with just pigtail wire would do, then you could use the wire to connect to the Arduino.

What model Arduino?
What is the actual output signal from the sensor module?
Can you post a link to spec/data of the module please?

Thanks.. Tom... :slight_smile:

3

Hi,

thank you for reply. I have read the manual how to use the forum before my first post. I thought that connecting SMA to Arduino is somehow general problem. That is why I didnt enclose the equipment.

Arduino model: Arduino UNO

Specsheet of photodiode

Manual of bias module

From specsheet of photodiode:
"This current can be converted to a voltage by placing a load resistor (RL) from the photodiode anode to the circuit ground." I dont know how to do this part.

Thank you for your answer.

4

I dont know how to do this part.

Choose an appropriate resistor for RL, consulting the data sheet, and connect it across the photodiode output.

Measure the voltage across that resistor to measure the current. Note that the voltage may be too small for the Arduino to measure.

None of your links work for me.

5

SMA is often used for RF/MW circuitry, which is generally completely out of the scope of Arduino
interfacing, its unusual to see a sensor with an SMA connector that is not RF/microwave. Get a female
bulkhead connector and solder wires to it? (Assuming its standard SMA, not reversed, both types exist).

[ BTW SMA connectors are rated to 18 GHz, and would used on communications laser receivers
because of high bandwidth used for such detectors - I presume you don't need such bandwidth! ]