Reading IR Pulses

Hey guys, bit of a weird but maybe easy question for some of you. I have a project that fires pulses of IR light from a laser and then reads the reflection sent back plus any interference. My goal is for the unit to be able to detect the presence (or lack) of the reflected pulses as well as detect any extra pulses from other units. IE: Unit fires a 200 hz, 10ns pulse and looks for that same pattern reflected back and/or other pulses that it did not expect (ones that are out of sync or do not match up with what it sent).

The board is based off of the atmega32u4 running 8mhz and 3.3v from a lipo battery. The transmitter is an osram SPL PL90. The receiver I am using is an osram SFH 2701. These will be mounted in an enclosure with a piece of black plastic in front that allows IR light but not visible light to pass. They will have walls separating them so that they don't reflect at each other inside the unit.

I was also thinking of using 2 identical receivers, one with an IR filter in front to have a comparison/baseline to compare the primary photodiode to.

I appreciate any ideas and suggestions to help me complete this project. Thanks.

So you are looking to time the reception of 10ns pulses relative to the sent pulse time?

You have a fast photodiode amplifier circuit already?

I am looking to compare the sent pulses to the received pulses and see if the received pulses are equivalent to the sent pulses + some time of flight or if there are variations.

I Have left the schematic open on the side of the optics circuitry because I am not sure what I need to do yet. I am willing to do whatever will make this work. :slight_smile: