Optional cooling fan

Hi,
has anyone enabled the optional cooling fan on the mendel90? The one that sits in the back side of the mendel....
How can it be achieved?

thanks!

To enable the optional cooling fan you`ll need a protected logic drive MOSFET or a MOSFET driver circuit like [www.thingiverse.com]

When you use a protected logic drive MOSFET the connection should be:

MOSFET drain -> black wire of the fan
MOSFET gate -> pin 6 of the Melzi 10 way expension header
MOSFET source -> pin 10 of the Melzi 10 way expension header
Red fan wire -> +12V FAN+ screwterminal on the Melzi

When you use the MOSFET driver circuit:

MOSFET Driver Fan+ -> red fan wire
MOSFET Driver Fan- -> black fan wire
MOSFET Driver Sig -> pin 6 of the Melzi 10 way expension header
MOSFET Driver 12V + -> +12V FAN+ screwterminal on the Melzi
MOSFET Driver GND -> pin 10 of the Melzi 10 way expension header

Please be very careful with the wiring. The Melzi can be easily damaged when the wiring isn`t correct.

After the fan is wired correctly you cann turn it on with "M42 P28 S255" and off with "M42 P28 S0".

To enable the fan in the Skeinforge profile provided by Nophead simply edit the end.gcode file in the ".skeinforge\alterations" in your userdirectory and remove the ";" at the beginning of the Lines.

Regards

Xerius

Edited 1 time(s). Last edit at 10/24/2013 11:21AM by Xerius.

I am currently implementing this feature. If you are not inclined to build the circuit on stripboard I can suggest the JeeLabs MOSFET Plug kit.

With the addition of a 6-way Molex KK Header, 6-way Molex KK Housing, 5-way Molex KK Housing, 11 Molex KK Crimp Terminals and 3 pieces of wire you can make a pluggable solution. I will document the process if anyone is interested.

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

Another option is to take 12 volts from the power supply and wire in to the fan via a simple switch and turn it on when you want to use it.

You don't need any circuit boards.

All I do is solder a MOSFET on across two pins of the header that fits on the expansion connector. Source is pin 10 and gate pin 6, which is two pins away and matches the legs of the FET. I then solder the fan lead to the drain tab and connect the other wire to the unused Melzi pan + terminal.

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[www.hydraraptor.blogspot.com]

nophead Wrote:
-------------------------------------------------------
> You don't need any circuit boards.

Yes you can do this but I would not want to make it difficult for future use of e.g. a Panelolu2 or other expansion interface. The PCB also offers two MOSFETs which would be a little awkward (not impossible) to mount on the header.

Regards,
Neil Darlow

---

I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

I would just unplug the the additional MOSFET and drive the fan from the one on the Panalolu2, which is on the same I/O pin.

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[www.hydraraptor.blogspot.com]

Quote
neildarlow
Yes you can do this but I would not want to make it difficult for future use of e.g. a Panelolu2 or other expansion interface. The PCB also offers two MOSFETs which would be a little awkward (not impossible) to mount on the header.

You could use something like one of these: http://www.rapidonline.com/Cables-Connectors/BKL-Electronic-Pin-Header-2-54mm-Pitch-3A-Gold-plated-521035

I can't remember the size of the expansion connector exactly but this gives you an easy, removable way of connecting a cheap mosfet in the way Chris describes with flexibility to upgrade to a Panelolu2 later.

THanks for alle the info, I will implement it soon.
Does anybody know about the other Controlpins on the 10pin Melzi header?
AFAIK pin 6 is FXT-A3 in the circuit, are the pins A1,2 and 4 unused too?

How about a slightly modified Y-Axis bar clamp with another micro switch that triggers the fan when the bed moves all the way back? Unless you're printing huge objects it shouldn't come on until the end...

No circuits, just a standard micro switch, wire and small print...

Hi Muelli,
If you are planning to controll the large "end of print cooling fan" from the end.gcode then the "G4: Dwell" command will be of value also. You will want the fan to stay on for 6 minutes or so, then switch off.
I use a different controller board on my Mendel90, but the end.gcode will be similar bar the Pin ref. I read somewhere that it works better to bread the Dwell into smaller time blocks, but I don't recall why that works better (could be bunkum). The last lines of my end.gcode are as follows and this is working excellently. I can forget about the print, and it's cooled down and ready to click off the print bed when I get back to it. (I also notice the G4 is sometimes exampled with a G4 Pxx syntax, but I've found the G4 Sxx to work fine.)
M42 P17 S255 ; Turn cooling fan on (IOS)
G4 S60 ; Wait 1 minute
G4 S60 ; Wait 1 minute
G4 S60 ; Wait 1 minute
G4 S60 ; Wait 1 minute
G4 S60 ; Wait 1 minute
G4 S60 ; Wait 1 minute
M42 P17 S0 ; Turn cooling fan off (IOS)

Regards,
NumberSix

thanks, that is a nuce idea!
nobidy knows about the other pins? used or unused? free for controlling other stuff?

Quote
muelli
thanks, that is a nuce idea!
nobidy knows about the other pins? used or unused? free for controlling other stuff?

I did a search on the RepRap.org Wiki using the term "MELZI" and was directed here: [reprap.org]

The schematic is there for you to download.

Alan

Thanks, but I already got the schematics!
I just need to know, if the other pins (A1, A2, A4) on the 10 pin header JP-16 are free for user control on the mendel90 or are used (maybe internally) for other things and cannot be controlled using g-code.

Edited 1 time(s). Last edit at 11/11/2013 05:24AM by muelli.

The signals are well-labelled and it appears that only EXT-A4 (Pin 8) is connected to the Debug LED. The others are unconnected.

I have Pins 6 and 8 connected to a JeeLabs MOSFET Plug as drive signals and Pin 10 for ground reference (grossly over-engineered I know but that is typical of me).

Regards,
Neil Darlow

---

I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

thanks, that is good news!

Hello all,

optional fan is installed and working.
I created a small PCB layout and etched it in my etching "machine", it offers a plug and play connection to the 10pin header on the melzi and has n-channel mosfets that drive three outputs using the spare pins on the melzi header (A1-3). It also has a 12V input line that can be wired to the 12v +FAN screwterminal, as the VCC on pin9 of the melzi header only offers 5V.

The outputs can then be controlled by
output 1 ON "M42 S255 P30"
output 1 OFF "M42 S0 P30"
output 2 ON "M42 S255 P29"
output 2 OFF "M42 S0 P29"
output 3 ON "M42 S255 P28"
output 3 OFF "M42 S0 P28"

I use the other outputs to controll the illumination of the Mendel90. But that is a project for another time

Edited 2 time(s). Last edit at 11/12/2013 03:10PM by muelli.

Good work muelli

Can you share some pictures and your schematic please?

Sure, board and schematic attached!
It is both in eagle format.

More Information and a little explanation about the how and why, along with some pics can be found in my blog (german) at
[blog.schmuffeln.de]

Edited 1 time(s). Last edit at 11/13/2013 03:57AM by muelli.