my target is detecting a laser generated with 1k frequency using a solar cell, i'm using this idea which is using a band pass filter on the solar cell to block the dc sun light and let me detect the laser, the problem is that i'm completely lost for how i would implement this in a circuit

i've calculated the RLC band pass filter to have 3kohm, .22h and .1uf, which is not bad to start with enter image description here

the solar panel i'm using is Mini Solar Panel 6V/250mA

but as i'm inexperienced in this field i'm kinda lost, so please either gimme answers or simple schematic

bunch of questions : q1- is the filter going to remove the dc volt coming from the sun and only leaves me with analog signal of 1k frequency ? aka if the sun will gimme 5v and the laser effect will be 20mv then will the filter o/p be +-20mv square/sin wave ? q2- i'm using microcontroller to read this input so how much current would that produce if i'm using the following schem.., do i need a resistor to limit the current and how would it affect the wave

enter image description here

  • \$\begingroup\$ possible duplicate electronics.stackexchange.com/questions/80801/… \$\endgroup\$ Feb 4, 2016 at 16:57
  • \$\begingroup\$ @MarkoBuršič I think it's okay. This contains specific design considerations and expands. I don't like the gimme answers part though. \$\endgroup\$
    – mcmiln
    Feb 4, 2016 at 17:51
  • \$\begingroup\$ I wish everyone who posted a crap video on youtub had to sit in here & answer all the duplicate questions that it spawns. In the end, user3761832, a pv cell IS NOT the best way to detect a laser in sunlight. A photoresistor, photodiode, or phototransistor, that is either tuned to the laser's wavelength, or has an optical filter that's tuned to the laser's wavelength is way better than a pv cell, and is less likely to be saturated beyond functioning by spurious light artifact. The 1KHz laser modulation helps with a small part of this, but when the "right" parts are cheaper, don't waste $$$. \$\endgroup\$ Feb 4, 2016 at 19:29

1 Answer 1


You could just do two passive RC's in series.


simulate this circuit – Schematic created using CircuitLab

I've made it a bit wide and sloppy... you can play with the capacitor values. The first part is a high pass with a 1 ms time constant ~160 Hz, the second is a low pass with a 10 us time constant. ~16kHz. You want to keep the second R big so it doesn't load the first stage.


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