Migbot Prusa i3 Unofficial Support Thread

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gatorNic
I suppose its possible it could be firmware, but honestly I don't think firmware just stops working unless the whole board gave out. Since it works on the x-axis we know the motor works. It's possible the E0 stepper on the board gave out (a fuse possibly, or something else). The mks board has a second extruder stepper connection for dual extruders. I would try plugging in the extruder motor to the E1 connection. Then, I believe, all you have to do is change the settings in the slicer to use the 2nd extuder. See if that works to help with the trouble shooting.

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kissfan4
I have had this printer for roughly 5-6 months, and it has worked pretty well since i got it, until yesterday.

So yesterday i started a print before i left for work, when i got home i had a mess, somewhere along the print something went wrong and the print had shifted to the rear by quite a bit (20-30mm) but the print continued and finished.

I tried printing something last night, and when the print starts you can hear the extruder motor "clicking" i pulled the motor out and clicked extrude, and the motor just clicks, i plugged that motor into the wiring for the "x axis" and it worked fine.

Switched everything back to the way it should be, tried another print, it started fine, then i got a jumbled mess on the lcd display, and the motor started clicking again. i started to eliminate potential problems so i tried 2 versions of Slic3r, pronterface, and Cura. all with the same results, could this be a problem in the firmware? This issues just popped up, i have been printing without issues for 5-6 months.

. If you think it could be a firmware issue, does anyone know where i could find detailed instructions on how to upload new firmware to the printer? I have no experience with this, i do have the Arduino software, but have never really gotten to play with it.

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evetanlm
Hi,

can anyone tell me how to change the code? my prusa have one issue whenever it extrude filament it restart, anyone know anythings to change the code?

// Travel limits after homing
#define X_MAX_POS 200
#define X_MIN_POS -15 // 0
#define Y_MAX_POS 200
#define Y_MIN_POS -45 // 0
#define Z_MAX_POS 180
#define Z_MIN_POS 0



    // set the rectangle in which to probe
    #define LEFT_PROBE_BED_POSITION 15   //0
    #define RIGHT_PROBE_BED_POSITION 190  //180
    #define BACK_PROBE_BED_POSITION 190   //120
    #define FRONT_PROBE_BED_POSITION 15  //-40

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kaffemustasj
So I just installed an automatic bed leveling sensor. Now the printer does not start printing at the midpoint anymore.
This leads the printer to go outside the printbed when printing large objects.
The printer does probe the bed at the correct corners, so th problem only seems to appear when printing and not probing.

I'm using a lj12a3-4-z/BX sensor.

Here is an exerpt from my config.h :

// Travel limits after homing
#define X_MAX_POS 200
#define X_MIN_POS -15 // 0
#define Y_MAX_POS 200
#define Y_MIN_POS -45 // 0
#define Z_MAX_POS 180
#define Z_MIN_POS 0



    // set the rectangle in which to probe
    #define LEFT_PROBE_BED_POSITION 15   //0
    #define RIGHT_PROBE_BED_POSITION 190  //180
    #define BACK_PROBE_BED_POSITION 190   //120
    #define FRONT_PROBE_BED_POSITION 15  //-40

  #define X_PROBE_OFFSET_FROM_EXTRUDER 12
  #define Y_PROBE_OFFSET_FROM_EXTRUDER 60
  #define Z_PROBE_OFFSET_FROM_EXTRUDER -0.8

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kaffemustasj
Thanks. I had no idea that the offsets where the values I had to fiddle around with.

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kissfan4
i am somewhat of a newbie still to 3d printing so i have to ask, when you guys are talking about your config file, how are you accessing it? I have the Arduino IDE but how do you find out what your settings are on your printer? When my printer is hooked up, and i open Arduino, i select the board, but have no idea how to see what the settings are. I would like to be able to edit them, because like many, my printer does not print in the center of the bed. Any help would be greatly appreciated.

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cmaet
Is there a way to connect the extruder fan to the board so that I can control it according to the hotend temperature?

I hate turning the printer off all the time, and the constantly running extruder fan bothers me even more, since the printer sits next to my computer.
I was thinking of adding a timer switch to it and connect the fan to the hotend heater: The fan would start when the hotend gets power, and continue to run a few minutes after the heater turns off. Then I figured, that it would be better if the extruder fan could use the thermistor information as a sort of thermostat - the fan runs if the hotend temp is higher than lets say 40 degrees and stops when it's lower than that.

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kaffemustasj
So I've just installed and calibrated a auto leveling sensor, however I'm getting some strange behavior.
When I print from the SD card, and the printer runs through the G29 command the Z axis only rises, without lowering.
This means the Z axis never triggers, and it gets higher and higher every time it tries to probe or home.
What can I do about this?

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gwc2795

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kaffemustasj
So I've just installed and calibrated a auto leveling sensor, however I'm getting some strange behavior.
When I print from the SD card, and the printer runs through the G29 command the Z axis only rises, without lowering.
This means the Z axis never triggers, and it gets higher and higher every time it tries to probe or home.
What can I do about this?

From Pronterface, Repeiter, etc issue the M119 command. The printer will tell you the status of each endstop. This will give you troubleshooting information. My first thought is that the Z-Min is triggered. Marlin firmware (by default) raises the head 5mm before each probe so it keeps going up and up each time you issue the G29 command.

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kaffemustasj

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gwc2795

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kaffemustasj
So I've just installed and calibrated a auto leveling sensor, however I'm getting some strange behavior.
When I print from the SD card, and the printer runs through the G29 command the Z axis only rises, without lowering.
This means the Z axis never triggers, and it gets higher and higher every time it tries to probe or home.
What can I do about this?

From Pronterface, Repeiter, etc issue the M119 command. The printer will tell you the status of each endstop. This will give you troubleshooting information. My first thought is that the Z-Min is triggered. Marlin firmware (by default) raises the head 5mm before each probe so it keeps going up and up each time you issue the G29 command.

Thanks man. The probe has a LED which lights up when it's triggered, and the LED does not show as triggered at some corners of the bed when probing.
Could this issue come because I'm stepping down the voltage with a LM7805 instead of using resistors in a voltage divider?

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Ax

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kaffemustasj

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gwc2795

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kaffemustasj
So I've just installed and calibrated a auto leveling sensor, however I'm getting some strange behavior.
When I print from the SD card, and the printer runs through the G29 command the Z axis only rises, without lowering.
This means the Z axis never triggers, and it gets higher and higher every time it tries to probe or home.
What can I do about this?

From Pronterface, Repeiter, etc issue the M119 command. The printer will tell you the status of each endstop. This will give you troubleshooting information. My first thought is that the Z-Min is triggered. Marlin firmware (by default) raises the head 5mm before each probe so it keeps going up and up each time you issue the G29 command.

Thanks man. The probe has a LED which lights up when it's triggered, and the LED does not show as triggered at some corners of the bed when probing.
Could this issue come because I'm stepping down the voltage with a LM7805 instead of using resistors in a voltage divider?

I had a similar issue with the stock Sensor on my first Migbot. The back right corner of the bed just wouldn't seem to trigger properly, and it just ended crashing the sensor into the bed. I had some copper tape lying around and stuck that to it as a test, triggered every time. I'm now on glass with sensor points made out of the same copper tape. Works a charm on both my Migbots, I'm actually almost at 4mm sensing distance due to this too. May be worth finding something metal, thin with a decent iron content and sticking it to the bed to see what happens.

In my limited understanding a Step-Down board would not fluctuate much below 5v. You should be able to test that with a Multimeter.

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kaffemustasj

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gwc2795

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kaffemustasj
So I've just installed and calibrated a auto leveling sensor, however I'm getting some strange behavior.
When I print from the SD card, and the printer runs through the G29 command the Z axis only rises, without lowering.
This means the Z axis never triggers, and it gets higher and higher every time it tries to probe or home.
What can I do about this?

From Pronterface, Repeiter, etc issue the M119 command. The printer will tell you the status of each endstop. This will give you troubleshooting information. My first thought is that the Z-Min is triggered. Marlin firmware (by default) raises the head 5mm before each probe so it keeps going up and up each time you issue the G29 command.

Thanks man. The probe has a LED which lights up when it's triggered, and the LED does not show as triggered at some corners of the bed when probing.
Could this issue come because I'm stepping down the voltage with a LM7805 instead of using resistors in a voltage divider?

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kaffemustasj
Yea, the voltage shouldn't drop below 5V. I'm wondering if that might be a problem?
Do you know if the sensor is supposed to give off an on/off signal, or a variable signal which varies with the height of the probe?

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kaffemustasj
So I measured the voltage coming of the voltage regulator and it was 2.33V, this was no good, so I changed it out with a voltage divider. The sensor now reads 3.2V.
However, how I've ran into another problem.
When I try to home the Z axis, the sensor lights up and triggers, but the Z axis keeps on lowering. This means the sensor and printhead slams into the printbed and keeps on trying to lower.

So I've tested with M119. The problem is that the sensor is always open, it never shows as triggered. This is although the voltage drops from 3.3V to 0 when a metal object is placed under the probe.

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gwc2795

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kaffemustasj
So I measured the voltage coming of the voltage regulator and it was 2.33V, this was no good, so I changed it out with a voltage divider. The sensor now reads 3.2V.
However, how I've ran into another problem.
When I try to home the Z axis, the sensor lights up and triggers, but the Z axis keeps on lowering. This means the sensor and printhead slams into the printbed and keeps on trying to lower.

So I've tested with M119. The problem is that the sensor is always open, it never shows as triggered. This is although the voltage drops from 3.3V to 0 when a metal object is placed under the probe.

I had the exact problem when I added the sensor to my Migbot. I disconnected the sensor from the pin and measured the pin voltage on the pin the sensor connects to and found it was supplying 5V. I tested various resistance values to find one that took the pin voltage to <0.2V when I connected it to ground. In my case that value was 680 ohm. I used that as the resistor that connects to the pin and ground in the voltage divider. A 1K resistor allows the voltage to rise to ~4V from the output of the sensor. The sensor I have is normally closed and opens when the bed is sensed. Before the changes to the voltage divider resistance values mine tried to go through the bed.

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kaffemustasj

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gwc2795

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kaffemustasj
So I measured the voltage coming of the voltage regulator and it was 2.33V, this was no good, so I changed it out with a voltage divider. The sensor now reads 3.2V.
However, how I've ran into another problem.
When I try to home the Z axis, the sensor lights up and triggers, but the Z axis keeps on lowering. This means the sensor and printhead slams into the printbed and keeps on trying to lower.

So I've tested with M119. The problem is that the sensor is always open, it never shows as triggered. This is although the voltage drops from 3.3V to 0 when a metal object is placed under the probe.

I had the exact problem when I added the sensor to my Migbot. I disconnected the sensor from the pin and measured the pin voltage on the pin the sensor connects to and found it was supplying 5V. I tested various resistance values to find one that took the pin voltage to <0.2V when I connected it to ground. In my case that value was 680 ohm. I used that as the resistor that connects to the pin and ground in the voltage divider. A 1K resistor allows the voltage to rise to ~4V from the output of the sensor. The sensor I have is normally closed and opens when the bed is sensed. Before the changes to the voltage divider resistance values mine tried to go through the bed.

Yeah, I'm guessing that's my problem. I measured 5V coming from the motherboard pins without the sensor connected.
When the sensor is connected to the board I'm reading 4.7V with a drop to 2.3V when the probe is triggered.
I've used a 15k ohm and a 10k ohm resistor in the voltage divider.

Could you draw your circuit in paint or whatever, so I'm sure I understand how to duplicate your connections?

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CrackinX
I'm having an issue as well with my Auto leveling in almost the same way as above, I have my sensor hooked to 12V and a V divider so the signal wire outputs about 4.5V, it is Normally closed so outputs 4.5V when NOT triggered. I have the endstop inverted in the firmware pullup disabled and all that. My issue is that when hooked up does nothing triggered or not it always reads as open. Power is hooked direct to 12V and Negative is direct to ground, 4.5V signal is hooked to the pin on the board that is not outputting 5V, hooked back up old endstop and everything is working fine there so it is something to do with the proximity sensor. Please help.

Oh for reference this is my sensor [www.amazon.com]