Slow down galvo scanner for lasertreatment of weeds

Hi,

I wan´t to detect weeds and treat them with a laserbeam. My objectdetection already has smooth results. To get rid of the weeds I´ve build an arduino based laser- scanner setup as you can see in this link:

As the guy in the tutorial I´m using this laserprojector repository:

It works perfectly for lasershows and small pictures and so on. But for my project I need the beam to slow dowm. I´m able to write an object in object.h that fits on the detected weeds on my picture. So if I had a really strong laser, I wouldn´t have a problem. But in my case the laser will have like max. 10Watts. So I need to slow down the scanner to go like 1cm/s.

I can´t find an option where to slow down the speed so I thought about setting single dots and wait for idk 10ms for the next dot close by. But I think that isn´t a nice way to do it---

Can you help me to find a way to slow the galvos down?

Thx a lot!!!

I can’t see your code.

Hi Awol,

The code is equal to the github repo I posted.

We always love this particular project - because we imagine what happens to the cat! :grinning:

Paul__B:
We always love this particular project - because we imagine what happens to the cat! :grinning:

I would expect the cat will have some interesting patterns in its fur after playing with a 10w laser beam.

Ghostrider5:
But in my case the laser will have like max. 10Watts.

Please remember: don't look in laser with remaining eye!

The project is irresponsible as all hell. I just hope that if anyone does get hurt, it's the OP.

This is from some one who has spent over 12 years controlling weeds for councils etc.

You CANNOT kill weeds with a laser.

  1. You may as well expect to kill a weed by giving a few pricks with a pin.

  2. Even if you could scan the laser beam across all the foliage in a reasonable time, it amounts to a contact herbicide and these won't work for long on perennial weeds in particular. They will just sprout new leaves and thumb their nose at you.

To have any chance of killing them you will need to deliver a dose of the recommended herbicide....still doable on a small scale with an arduino and, for example, a windscreen wiper pump.

What ANY IDIOT CAN DO is get a laser beam refracted in a drop of water and BLIND SOMEONE.

But I think that THE IDIOT will only think of what THE IDIOT had in mind. They usually do.

I loved to read your critics. The project is for work, we have a laser security agent who will do an assesment of risk later. The laser will be housed to reduce the laser class 4 to 1 (according to DIN 60825).

Other people build engraving machines with strong laser diodes and you´re willing to help them aswell.

boylesg:
This is from some one who has spent over 12 years controlling weeds for councils etc.

You CANNOT kill weeds with a laser.

A colleague of mine wrote his dissertation about it. To be precise I don´t want to kill the weed, I want to constrain it´s growth. The point is to get rid of herbicides because they are bad for the environment. Also I could show you that you can "kill" them if you want. It´s another problem that they spread somewhere else. So killing these aswell would solve the problem.

Please help with constructive ideas!

Thanks:)

Laser engraving machines are a very different thing. For starters little risk of injuring innocent bystanders.

You want to slow down something, but don’t give the actual code you intend to use, nor schematics of the actual machine it has to control.

Do you have code already that reliably aims the laser to the correct point, based on your camera? This is much harder in a 3D environment (weeds are at different distance, you have to take that into account when aiming your laser) than in a 2D environment (engraving kits).

The code and the machine are described in the given links.

To create a pattern I use objects.h and create an object like:

const unsigned short draw_max_rectangle[] PROGMEM = {

0x8000,0x7FF,
0x8000,0x0,
0x87ff,0x0,
0x87ff,0x7ff,

};

you have x and y axes in two bytes:

0x8000 starts the laser (only in the first byte).

numbers from 0x0 to 0x7ff are equal to the displacement of the galvo.

I hoped that it is possible to control the speed between those 4 coordinates. I have problems with my actual camera but for the resolution of 1280x960 I suggest to divide the maximum range of the galvos into 1280 parts for both axes (for the second axis there is an option for maximum deflection so that it won´t go more than 960 pixels).

In the planned application all weeds are on (nearly) the same level ("pseudo" 2D). Later on we are planning to get 3d data aswell but one step at a time!

Details matter big time, that’s why I was asking for your ACTUAL code and your ACTUAL machine.

You’re now talking about some camera, that’s apparently different from what’s used in those links (which, as they are not your ACTUAL machine, I didn’t bother to put the effort in of copy/pasting and then reading about something that is possibly similar but different from what you’re working on).

I bought the exact same parts and built the exact same machine.

I used the exact same code as in the github repo. The only thing I added in object.h is the object that I described in my last post.

Ghostrider5:
The project is for work, we have a laser security agent who will do an assessment of risk later.

He should be doing the assessment at the start, not the end of the project.

Have you even mentioned it to him yet?

Ghostrider5:
Other people build engraving machines with strong laser diodes and you´re willing to help them aswell.

Inside of a containment. There's a reason for it.

Just because you or someone else gets help with something from someone doesn't make it a sound idea.

No I just waste my companies money:D Sure I did! I have security conditions to care for. But in the end it will be testet and reviewed.

In the mean time I could find a solution for my problem. Three ints via serial and a delay.