<p>I recently discovered this kit after reading this Instructables, <a href="https://www.instructables.com/id/Adding-More-Extruders-to-Any-3d-Printer/" rel="nofollow noreferrer">Adding More Extruders to Any 3d Printer</a>: </p>

<blockquote>
  <p><a href="https://i.stack.imgur.com/Lq4uQ.png" rel="nofollow noreferrer" title="New CNC Shield v3 engraving machine / 3D Printer / + 4pcs A4988/DRV8825/AT2100 Driver Expansion Board for Arduino"><img src="https://i.stack.imgur.com/Lq4uQ.png" alt="CNC Shield v3 engraving machine / 3D Printer / + 4pcs A4988/DRV8825/AT2100 Driver Expansion Board for Arduino" title="New CNC Shield v3 engraving machine / 3D Printer / + 4pcs A4988/DRV8825/AT2100 Driver Expansion Board for Arduino"></a></p>
</blockquote>

<p>I'm pretty sure I can use this kit with my board since it uses the same drivers as mine. But that's for motors, not fans. And while I know G-code pretty well, I'm not sure how I would use this to activate and deactivate a fan from G-code. There is probably a better way to do this.</p>

<p>The board I am using is from an FLSUN Large Scale 3D printer. Here is a picture of the board: </p>

<p><a href="https://i.stack.imgur.com/Bq8w1.jpg" rel="nofollow noreferrer" title="FLSUN printer board"><img src="https://i.stack.imgur.com/Bq8w1.jpg" alt="FLSUN printer board" title="FLSUN printer board"></a></p>

<p>There appears to be only one labeled pin for the fan. BUT even if there are other pins that I don't recognize, they would have to be controlled by a micro controller (G-code commands). There appear to be a bunch of un-used pins in the bottom right of the board. But if this board just can't do it, there is a newer board here: [link removed]. </p>

<p>It does seem like it is using Arduino and the newer board might have extra pins for a fan. But at that point, would it be easier (cheaper) to just control the fan from the extruder extender kit? Would I just set it as an extruder with a really high filament extrusion speed and send appropriate G-code commands when needed to run it at max voltage?</p>

<p>I know on my Lulzbot Mini there is a "parts cooling" fan which allows you to cool off the layers as your structure rises vertically. This is a fan I want. The parts cooling fan <em>must</em> be controlled by the micro controller. It only comes on when printing vertically.</p>

<p>I would like to actually add two fans like this to my 3D printer. One of them is a >= 5&nbsp;V cooling fan like above. Another is a regular 12&nbsp;V cooling fan for an extra extruder that I am adding.</p>

[{'answer_id': 10514, 'author': 'Trish', 'author_id': 8884, 'author_profile': 'https://3dprinting.stackexchange.com/users/8884', 'pm_score': 3, 'selected': True, 'text': '<p>The <a href="http://www.robotrebels.org/index.php?topic=769.0" rel="nofollow noreferrer">MKS Gen L v1.0</a> Board you are using does support microcontroller controlled fans without doing some surface level modification to the board via the <code>D9/FAN</code>. The port you marked FAN is not a controllable port, it runs a direct 12/24&nbsp;V all the time and should be used for the Hotend cooling solution. The ports <code>D7/HE1</code> and <code>D10/HE0</code> are for two hotendes, corresponding to <code>E0</code> and <code>E1</code>.</p>\n\n<p><a href="https://i.stack.imgur.com/YlGDW.png" rel="nofollow noreferrer" title="MKS Gen L port/pin layout"><img src="https://i.stack.imgur.com/YlGDW.png" alt="MKS Gen L port/pin layout" title="MKS Gen L port/pin layout"></a></p>\n\n<h2>Variant A: Swappy Fans</h2>\n\n<p>This is the more tricky variant and does need both coding and wiring expertise.</p>\n\n<p>You\'ll have to run both hotend cooling fans via that one port in the top left corner. Make sure they are running fast enough to keep the heatsinks cool and prevent heat creep!</p>\n\n<p>Your <strong>custom</strong> Firmware will have to define <code>D9</code> as a microcontroller controlled Fan instead of a 100&nbsp;% running fan as the normal firmware is most likely.</p>\n\n<p>Without extra hardware, you can\'t get 2 individually controllable ports from <code>D9</code>, but you can use, the fact that you don\'t want part cooling for a hotends in \'resting\' position. So a pair of couple Normally Closed switches cab achieve disabling of the resting hotend\'s part cooling fan:</p>\n\n<ul>\n<li>make a wire splitter for D9, so that you have both <code>+</code> and both <code>-</code>-wires connect to the one <code>+</code>/<code>-</code>-pin on the board. You\'ll have the part cooling fans in parallel now. \n\n<ul>\n<li>Do the same for the Hotend Cooling Fans!</li>\n</ul></li>\n<li>connect each <code>+</code>-line to a Normally Closed switch, which is installed on the hotend in a way so it triggers and opens the line if the hotend is in the resting (homing) position.</li>\n<li>As the line connects when the hotend moves into the build volume, the part cooling fan on the currently active hotend starts to spin while the one of the non-active hotend is isolated.</li>\n</ul>\n\n<h2>Variant B: MOSFETs and Safety</h2>\n\n<p>An alternate source for the part cooling fan signals might be the SERVOS1/SERVOS2 group, where <code>D4</code> to <code>D6</code> and <code>D11</code> are accessible. This leaves the FAN and top-left 12\xa0V pinnings free for the hotend cooling. The downside is, that these pins don\'t likely provide 12\xa0V but at best a 5\xa0V digital output. However, a 0 to 5\xa0V signal can be used to control a separate MOSFET which outputs 0 to 12\xa0V, which then can power the part cooling fans. Due to the power draw of the Fans, a simple step-up converter is not a solution it needs a separate power supply.</p>\n\n<p>The Main benefit is, that this does draw less power from the board than Variant A and does not re-pin <code>D9</code>. The "Cooling Fan Board" could use a 6-line ribbon cable to connect to the <code>SERVOS1</code> pins, using the 5V as reference for the MOSFETs, <code>D4</code>/<code>D5</code> as the trigger signal and GND as return lines.</p>\n\n<p>A pre-assembled board that could serve in this position would be a <a href="https://howtomechatronics.com/tutorials/arduino/arduino-dc-motor-control-tutorial-l298n-pwm-h-bridge/" rel="nofollow noreferrer">L298N Driver</a>. Due to how it is set up, one could run both part cooling fans, if their speed is set up to be always equal.</p>\n'}, {'answer_id': 10521, 'author': 'towe', 'author_id': 13171, 'author_profile': 'https://3dprinting.stackexchange.com/users/13171', 'pm_score': 2, 'selected': False, 'text': '<p>You can use the <code>M42</code> g-code to manually set any supported digital pin, which can then be used to either enable one of the on-board MOSFETs (D7, D8, D9, D10) or an external MOSFET.\nFor example, <code>M42 P9 S255</code> would enable the parts cooling fan at 100&nbsp;%.</p>\n\n<p>You should never run any fan or heater directly off of a microcontroller pin (the ATmega2560 on your board supports up to <strong>40&nbsp;mA</strong>. Standard 5&nbsp;V fans I found online tend to draw <strong>100&nbsp;mA</strong> or more).</p>\n\n<p>Your board supports up to four switchable "power" outputs - bed, heater 0, heater 1 and FAN.\nDepending on what you use so far, one of those may be usable for your fans.</p>\n\n<p>Note that on-board MOSFETs usually switch the ground side of the connected device.\nThis means that you for your 12&nbsp;V fan, you can connect it directly to one of those connectors.\nThe 5&nbsp;V would have to receive +5&nbsp;V from elsewhere (like the +5&nbsp;V pins near the bottom right mounting hole), but you can still control the fan by connecting its ground lead over one of the on-board MOSFETs.</p>\n\n<p>If four MOSFETs are not enough for you, the L298N module provides an easy way to control four additional fans, while using normal digital pins to control the L298N.</p>\n'}]
['https://3dprinting.stackexchange.com/questions/10513', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/10369/']