Hi Folks.
After the success of my Diode Laser additions which is working brilliantly for me.. I am looking at other hardware things I can do.
One of my personal peeves is the Autofocus Pen. It a long item that needs to hang below the laser head, and will get caught up on any weight, clamp, or Magnet one might use to hold the work down.
I think I can do better…
In 3D printing they use a range of light touch, or non contact method to set the Bed height.. Some of these items can be very accuate upto 5 or evedn 10cm away from the bed.
I am thinking of using one of these with an Arduino. You have a variable resistor on the Arduino that sets the focus millimeters that you want.. And then you press Auto Focus.
The controller will raise the bed until the Arduino senses the correct height (Sonar, IR Reflection, Lidar) and it will then send back a pulse telling the controller the focus hieght has been set.
Due to the size of some of these sensors it can be put very close to the lens cap.. or even rotated up and out of range when not in use.
The advantage is the lowest things to your work should only be the laser head.. nothing else.
Let me know what you all think. It will be a plug in compatible for the existing Auto Focus Pen Switch
Dave
P.S. Also looking at using an ESPCam to monitor your laser for you
Regarding the ESP32Cams, I used them a lot a few years ago (in smart home context), but I found them not to be very reliable. They tend to break down after a few months of constant use. So I use a webcam with a streaming server for monitoring. The control laptop is always close to the laser, as such, it can handle the streaming as well.
That’s exactly why I don’t want it. I’ve seen some terrible crashes up this way.
I’ve long looked enviously at the newer and more expensive machines with built-in non-mechanical distance meters.
I made this primitive sensor based on what you plan to make. It works very precisely but is only semi-automatic out of laziness. I have to start a Wifi connection to the sensor with my iPhone to see the water level, or lift the lid to see the small display, it doesn’t matter - it works.
I would love a compact solution with an interface to connect to the laser. I am also surprised that there is no ready-made solution on the market yet.
I also see potential applications in bed leveling / material flatness control. Being able to see the distance measurement live will be loved and will surprise some users about how crooked their machine bed is.
Also a good idea, if the frame rate and transmission speed are good enough it should also be possible and would be useful.
I’m not good at Arduino/Python programming, but I have some of the necessary components lying around here, so I’d like to play around / spar if that’s what you’re looking for.
If you just want to see if there’s a market for your ideas, I’m interested too.
Hi and many thanks.
The VL6180X 50cm looks to be a good fit. Plus an ESP32 with an OLED.
You can initally raise the laser bed until the laser head is touching the work..
You press a button to set ZERO.
Then use a button to press each 1mm you want as the focal height.
Then lower the bed down to say 10cm.. and start the “Set Focus” controller. The bed will be raised till it hits the set Focal Height and the ESP32 will sent the signal to the Controller.
Alternatively your can do the raising till the head touches the work.. and then press the ZERO buttoon. Then raise or lower the bed and see the value on the OLED.. This will work for all beds including ones with no Auto Focus.
That sounds good.
I’ve just watched a few fiber laser videos and don’t understand why the manufacturers often deliver them with a wooden or plastic stick to adjust the focus with… when a simple electronic device can be integrated reasonably cheaply. Here I’m not even thinking about autofocus but only a precise reading of the distance to the material surface and the associated visualization on a nice display.
A couple of the parts have already arrived, and when the rest arrive I will be starting to work on it.
Only big mod issue will be to run 4 small wires from the control area to the laser head. otherwise everything is just connectors.
I managed to thread silicone ribbon cable through both drag chains to fix the autofocus “pen”, but I had to dismount the X axis chain for enough elbow room:
Crimping a connector in the middle divides the task into two smaller pieces:
I have run out of room in my chain guide so I am opting to a larger one that can handle a few more cables.
With my laser the horizontal bar is hollow and the cables exit half way along. So to preserve tension I am adding a DB9 that is mounted on the bar.. and a corresponding DB9 where it enters the chain guide.
So it will be easy to disconnect the chain if necessary.
I don’t quite understand why you have to zero by driving the laser nozzle to the material surface first. It could only be an option for lens change (new setpoint 0)
If a focus distance is first set in the processor, e.g. 50.8mm, you should be able to use it permanently. That is, the VL6180X always measures the distance and the processor/lcd shows the difference to “0” with + or - values. And/or then the processor can be used to “react” to button presses to give a calculated signal to the table height stepper motor control.
David, I am absolutely no expert in ESP32 and Arduino IDE, I can hardly remember how I could program my water sensor for the fresh water tank in my RV (…probably with AI …). But here I have measured and determined the min and max in my tank and all calculations are based on these 2 values. I could imagine that for all lenses (there are only 1 to max 4 pcs.) the 0 point must be specified either with OTA or USB, it should not take long. Whether it is secure enough in the end for a laser machine, I do not know, but I will not be afraid to test.
Give me a hint if you want to see my script for my water level device.
Many thanks for the offer.. But I should be fine. I have programmed Arduino for quite some time.
Essentially the VL6180X TOF sensor returns back millimeters.. So I need to take a Zero setting where the leser head is touching the surface. And then use that to subtract from the returned value as the bed moves up and down.
Sounds like you’re smart enough, but how to you tell it material thickness? You need to focus at the half way down point.
Wooden and plastic sticks are used as they are cheap. Even though you say you can make electronics at low cost, nothing is lower cost than a stick. It also adds to the cost of the device and makes them ask more money for the machine.
All comes down to money and how much each of us, including manufacturers, wants to spend.
..don’t agree, there should definitely be room to play with technology a little, life is too short not to have fun.
Regarding finances, how many people here do you think will get their investment in the machines they bought back from what they sell on Etsy or the street?
You can’t buy everything in life for money
PS. material price for an electronic solution is approx. a third of what the cheapest electrical/mechanical solution (for CO2) from China costs.
If you have a focus distance other than 0 and want an electronic solution for that, you will need extra components and programming or you will need to intervene manually, just like you would with all other machines, including those with electronic autofocus.
Set Home Offset to fully release the switch after autofocusing
Set Focus Distance to whatever puts the nozzle at the correct focus height from the surface after autofocusing
Switching lenses is a matter of adding / subtracting the focal length distance difference to the Focus Distance, after which autofocus Just Works™ with the new lens.
All of which depends on the physical location of the focus pen in relation to the nozzle, so moving the pen will require changing the Focus Distance to suit. The Home Offset doesn’t change, because that just releases the switch after it closes on the surface.
@marcwolf’s setup is better, because it doesn’t have anything hanging below the nozzle. You might be able to wire that into the controller to simulate the switch closing, after which the Focus Distance setting would automagically set the proper focus.
Not exactly, it’s more the technical challenge than the $10 or so that the materials for the project will cost that I’m willing to contribute. Personally, I’d be happy to just get a display in mm and then turn my handle a quarter turn up or down, like I’ve always done… But if/when I ever get a UV laser I’d rather not use a wooden stick to adjust the focus, it just doesn’t match the rest of the expensive advanced technology.
…let’s not forget the fun either
…). But here I have measured and determined the min and max in my tank and all calculations are based on these 2 values. I could imagine that for all lenses (there are only 1 to max 4 pcs.) the 0 point must be specified either with OTA or USB, it should not take long. Whether it is secure enough in the end for a laser machine, I do not know, but I will not be afraid to test.