I recently took up a rather ambitious project for my skill level as I have never worked with almost all involved components before.
I would be very grateful if you could help me find the best components to hopefully make this work.
What I am trying to achieve is this:
A laser beam is shining at a spinning polygon motor, creating a laser scan field α.
Within this I want to be able to detect if a small object enters the field and be able to deduce the angle of detection β.
The distance of the object will be anything from a few cm to up to 2m.
What I am expecting to get in the end is a scope reading that looks something like this:
where at 300Hz (50Hz motor spin x 6 sides of the mirror) I get sort of a constant signal landscape and a peak to whenever an object enters the scan field.
I have never worked with photodiodes before, but I read about the an avalange photodiode would be best for this.
I have also found some APD modules, which sound like that's what I need, but they seem to go for around 300$ - definitely not in the scope of this project.
But then there is the question about sensor size, with or without preamp and also where and how do I actually place the photodiode to get the return signal? In my sketch i placed it next to the laser as I had seen modules where this is done that way. But is this suitable to my setup?
I am a hobbyist and I am doing all of this by trial and error, so apologies if some of my questions have obvious answers. Thank you.
I would be very grateful if you could help me find the best components to hopefully make this work.
What I am trying to achieve is this:
A laser beam is shining at a spinning polygon motor, creating a laser scan field α.
Within this I want to be able to detect if a small object enters the field and be able to deduce the angle of detection β.
The distance of the object will be anything from a few cm to up to 2m.
What I am expecting to get in the end is a scope reading that looks something like this:
where at 300Hz (50Hz motor spin x 6 sides of the mirror) I get sort of a constant signal landscape and a peak to whenever an object enters the scan field.
- the polygon motor spins at 50Hz precisely
- the laser beam is at 650nm. I use this laser module
- as part of this project, I am currently I am trying to get a useful reading out of this photodiode: SGPD3027C. But I already suspect this is not a good choice for this project at all.
- further down the project, I would like to also modulate the laser, so within that peak in the second sketch should be also a visible modulation waveform.
- Eventually, given that I get all this working, I would like to repeat the test with an infrared laser.
I have never worked with photodiodes before, but I read about the an avalange photodiode would be best for this.
I have also found some APD modules, which sound like that's what I need, but they seem to go for around 300$ - definitely not in the scope of this project.
But then there is the question about sensor size, with or without preamp and also where and how do I actually place the photodiode to get the return signal? In my sketch i placed it next to the laser as I had seen modules where this is done that way. But is this suitable to my setup?
I am a hobbyist and I am doing all of this by trial and error, so apologies if some of my questions have obvious answers. Thank you.