Seeking V-plotter firmware options

Hi, so as the title implies, I'm looking for firmware to run my v-plotter on. I've just built a quick and dirty model right now to get familiar with how it works. Eventually I'm willing to make a machine that the ability to create bigger than A0 drawings but let's start with something smaller. The firmware side however, is a bit difficult, I haven't been able to find a suitable solution.

First stage, setting up the frame:


The specs are as follows:
- Ramps 1.4
- Reprapdiscount Smart Controller
- 2x A4988 (since I have like 20 left over, also soldered ROSC pin to ground)
- No endstops
- 1x Servo
- 2x weights on the outside 100 grams per piece
- 1x support weight under carriage of 50 grams
- All parts are reused from salvaged machines or other trash or second hand, but basically the only thing I paid for were the belts
- Paper and ink should also be environmentally friendly
- Expected draw area ~550x750mm
- Aluminium frame can be placed on top of any piece of wood so it's basically a module with an aluminium U-profile that can be placed over any desired plate
- Easily upscalable, still working on a version 2.0 that is more lightweight and has suction cups as an option.

And now, the problem I'm running into, I have found multiple firmwares but they all have quirks causing it not to work with my set of ingredients:

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Makelangelo firmware
Website http://www.makelangelo.com/
Link to Firmware https://github.com/MarginallyClever/Makelangelo-firmware/releases

Nicely designed open source firmware and software for their own v plotter model. Can also be used for personal projects.

Pros
Works well with Ramps, RRD LCD. Also they have their own software that works together with their own firmware.

Cons
Sadly the versions of this firmware I've found need endstops to work, now I can of course add endstops, but I like the simplicity of the system without using endstops. I have not been able to figure out of I can use the latest firmware without endstops since their forum is really quiet.
Rotary encoder doesn't respond well to movement, in Marlin it works flawlessly and I haven't been able to find out where to tune this.

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Polargraph Controller
Website http://www.polargraph.co.uk/
Link to Firmware https://github.com/euphy/polargraphcontroller/releases

Personal open source/semi commercial project by Sandy with it's own software suite as well.

Pros
Easy to setup, supports ramps: [github.com], no need for endstops, big plus

Cons
RRD LCD is not supported and I don't know what LCD to use to make this work. I am not going to run the v plotter from my laptop as I want it to be standalone printing from an SD card

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Repetier firmware Polargraph version
Website http://www.polargraph.co.uk/forum/polargraphs-group2/code-software-forum2/repetier-version-of-polar-graph-thread444.0/
Link to Firmware https://github.com/RickMcConney/PenPlotter

Awesome piece of firmware based on Repetier firmware adding very smooth and precise movement to your v plotter

Pros
Smooth lines, precision, flexibility, supports Ramps, LCD, etc.

Cons
It doesn't compile!!! I'm pulling out my hair. I used four versions of Arduino IDE, from 1.6.2 - 1.6.9 - 1.8.4 and 1.8.9 And different versions give me different errors. So I'm hoping for a solution some day but it's very quiet over at their Github.

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If anyone has another piece of firmware for me that works with Ramps, LCD and is suitable for a v plotter without endstops. Let me know. I would really like to progress in this project

Edited 3 time(s). Last edit at 02/20/2020 06:16AM by Ohmarinus.

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http://www.marinusdebeer.nl/

Okay, so I tried working with the Makelangelo firmware and burned up two Mega's. On the one the SD card doesn't register anymore and on the other the motors now only move in the same direction and one stepper driver got burned. I have NEVER ever had this happen to me before and I've built around 8 machines that work with Ramps and I've never burnt through anything.

There are three possible issues:
- Makelangelo firmware is breaking the Mega board
- The servo I'm using has a short and is burning up the Mega
- One of the stepper drivers was faulty and caused an internal short

The machine worked well for one round, after that suddenly the LCD screen would go full brightness at random and the machine stopped working. After this I had a whole host of problems:
- With the other set of stepper drivers one of the two drivers doesn't work anymore, swapping them out for new ones solves this problem
- Machine only draws straight lines up and down or left to right with working stepper drivers (indicating the issue might be in the mega)
- Browsing SD card shows no files (swapping the Mega fixed this)
- When the servo starts, the Mega restarts

I'm lost here.. I tried two different LCD panels, both work fine, no shorts, tried two Ramps boards, both work fine, tried two Mega's, these are now fried I assume but I have no way of testing this assumption. Also tested two different PSU's as I initially thought this was the problem.

There have been no shorts made by me.

Now that I'm writing this all down, it might be that the servo is the problem. What happens when a servo shorts 5v to the signal line? Can is cause these issues?

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http://www.marinusdebeer.nl/

How big is the servo, and where are you getting the 5V power from? Servos dump power into the 5V power rail when they decelerate. I measured the 5V rail on a Duet rising to 8V when using one particular type of servo. The Duet withstood this, but an atmega powered directly from the same 5V rail might not.

In later Duet revisions we increased the amount of capacitance on the 5V rail from 20uF to 240uF to absorb the surge.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42
How big is the servo, and where are you getting the 5V power from? Servos dump power into the 5V power rail when they decelerate. I measured the 5V rail on a Duet rising to 8V when using one particular type of servo. The Duet withstood this, but an atmega powered directly from the same 5V rail might not.

In later Duet revisions we increased the amount of capacitance on the 5V rail from 20uF to 240uF to absorb the surge.

Hi DC42, thanks for your reply!

The Makelangelo firmware has a spot reserved on the Ramps 1.4 so it's getting it from the 5v rail next to the D4 pin. It's the first servo connection directly next to the PS_ON and 5v-throughput jumper.

I haven't had this problem before, however, similar issues, with a Ramps board having intermittent problems such as random reboots and hiccups. After replacing the servo on the other machine, it hasn't had problems ever since so I'm wondering if a bad servo might mess up a mega board.. It's bad news.

Would you think adding a capacitor between the + and - of the servo will help mitigate this surge? The movements aren't big and the servo's I'm driving are microservo's like SG90 and MG90. I have both plastic and metal geared ones. I wouldn't expect them to cause a big surge.

I will try to remap the pinouts for the stepper driver from Y-axis to Z-axis stepper and replace the servo to see if the problem was caused by the servo. I believe the pins for the Y-axis have been burned or shorted permanently since the X- and Y-axis both turn the same way no matter what I try.

Update:
I changed the stepper drivers all around the ramps with no result. The motors keep spinning in the exact same way. Motor A is copying the behaviour of Motor B.
Sadly the one mega has a burnt SD-card slot and now this one has a burned stepper driver controller, it seems all movement control is just shorted together, maybe inside of the chip?

Since the Corona virus is happily blocking all Aliexpress orders I need to get my hands on a mega. This project was supposed to run on 2nd hand and trash electronics, but now that I've burned through all my boards it's over for this project. Maybe I should just get an SKR 1.3 and be done with it haha. Ooh crap, the Makelangelo firmware doesn't work on the SKR 1.3... Maybe I should create my own file for it then.

Conclusion:
How can I safely drive a servo on a Ramps 1.4 board without blowing the Arduino Mega? I can pull the control board from my laser cutter that I rarely use and meanwhile order a new Mega board to use on the laser cutter when it arrives in a few weeks.

Update 2:
Tried the mega from my laser cutter with the ramps it's using and the motors still spin the same direction. I haven't changed anything in the firmware and this ramps + mega board are confirmed working!! What's happening!? I'm losing my mind.

What I did:
- Download fresh firmware to make sure it wasn't a typo I made
- Replace the mega board with a working one from my laser cutter
- Reuploaded the Makelangelo firmware
- Replaced stepper drivers
- Created a new gcode file to be sure it wasn't corrupted somehow

But still the motors make identical movements


Here's a video of what's happening:
[www.youtube.com]

And to proof it ran fine before this:
[www.youtube.com]

Edited 6 time(s). Last edit at 02/22/2020 11:40AM by Ohmarinus.

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http://www.marinusdebeer.nl/

The voltage regulator on an Arduino Mega can't even power the Arduino + RAMPS (which takes very little) + a graphical LCD without overheating, let alone a servo. Get yourself some decent electronics.

Quote
Ohmarinus
Would you think adding a capacitor between the + and - of the servo will help mitigate this surge?

Yes, if that's what the problem is. But as you are powering the servo from the Arduino, it may be that the real problem is that you are burning out the voltage regulator.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42
The voltage regulator on an Arduino Mega can't even power the Arduino + RAMPS (which takes very little) + a graphical LCD without overheating, let alone a servo. Get yourself some decent electronics.

Quote
Ohmarinus
Would you think adding a capacitor between the + and - of the servo will help mitigate this surge?

Yes, if that's what the problem is. But as you are powering the servo from the Arduino, it may be that the real problem is that you are burning out the voltage regulator.

I have managed to fix all the other issues. I will use a buck converter to tap the 12v down to 5v and connect the servo this way. So I will only use the signal pin from D4. Might this be a suitable solution as well? Not sure if this works, but I'll do it right now.

The goal of my project is to use waste electronics and materials, so 'decent electronics'.. I wish I managed to get everything running 'kinda' right now.

Update;
It seems to hold up with the 5v coming from a separate source. I'm looking for a replacement voltage regulator, I hope the local electronics shop has one!

Edited 1 time(s). Last edit at 02/24/2020 11:17AM by Ohmarinus.

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http://www.marinusdebeer.nl/

Quote
dc42
The voltage regulator on an Arduino Mega can't even power the Arduino + RAMPS (which takes very little) + a graphical LCD without overheating, let alone a servo. Get yourself some decent electronics.

Quote
Ohmarinus
Would you think adding a capacitor between the + and - of the servo will help mitigate this surge?

Yes, if that's what the problem is. But as you are powering the servo from the Arduino, it may be that the real problem is that you are burning out the voltage regulator.

I wanted to conclude part of this thread and thank DC42 for the tip about the regulator. Indeed, I managed to get a new identical voltage regulator locally (bought two for €1) and replaced it and boom, the Mega2560 is back into business.

Meanwhile I have worked the Vplotter to it's adult stage and lost interest once I found out how bad the precision was and how a Vplotter is mostly good for messy designs and not for precision geometry. Precision is possible but at a high cost of speed. For large murals it might still be nice to design a custom plotter some day, but for now I will go back to focus on the CoreXY pen plotter I have built and do some major improvements on that machine first.

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http://www.marinusdebeer.nl/

Marinus I’m in almost the same exact spot as you, but I’m not having brownouts from using the servo because I don’t have it connected currently. Using marlin on ramps I can only get it to move in one direction. Did you ever pin down what the cause of that was? If you have a copy of your marlin config I would absolutely love to see that.