https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/ Prusa3D Forum Discussion Board en-US Fri, 05 Jun 2026 23:16:09 +0000 wpForo 60 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-39293 Sun, 13 Aug 2017 11:15:26 +0000
I have found a pin very easily accessible and not used by the firmware.
It's pin PC5 of the Atmega, named 32 on arduino.
This pin goes to IO extension header P2 pin 10


this header connects to the LCD panel Header 5X2 pin 10 (close to the reset pin)
see schematics here : http://reprap.org/mediawiki/images/7/70/Controller_final_reprapdiscount.pdf
you can easily solder a wire on the connector pins
On the following picture, it is the big black connector on the right, and the top right pin
On the same row, the pin close to the connector is ground (it's not visible on the picture)



You can access this pin via Gcode with the original Prusa i3 MK2s firmware :
M42 P32 S255 to switch ON
M42 P32 S0 to switch OFF

JP]]> Others (Archive) freedom2000 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-39293 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-39107 Thu, 10 Aug 2017 10:37:04 +0000
I have just completed the implementation of a LED controlled by the X-MAX pin available on the RAMBo Mini board.

As previous posts have mentioned, I had to change the source code in the firmware, compile it, and upload it to the 3D-printer, but is was quite easy. I just had to change two lines, so this is a change i happily make whenever I need to update to the latest firmware.

I made this change in the file Pins.h:
#define X_MAX_PIN 30 to
#define X_MAX_PIN -1 You will need to make this change two places in the file to make sure it's valid for both versions of the RAMBo board.

Just reply to this thread if anyone needs more detailed information on how to obtain the source code, compile it etc.

Regards,
Erik]]> Others (Archive) eriso https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-39107 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-37994 Tue, 25 Jul 2017 11:19:32 +0000 Looks like these pins have been use for the Dyze run out sensor:

The question is are these pins GCODE enabled in the stock MK2 firmware? Hi david.b14,

check this out for filament runout sensor http://shop.prusa3d.com/forum/improvements-f14/system-that-allows-to-stop-printing-automatically--t5006.html
I changed the FR_SENS pinout to y-max.]]> Others (Archive) 3d-gussner https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-37994 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-37421 Mon, 17 Jul 2017 13:05:42 +0000
DSO 138
https://www.amazon.com/gp/product/B06XT6K6CF/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1



https://www.thingiverse.com/tag:DSO138/page:1]]> Others (Archive) david.b14 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-37421 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-37222 Fri, 14 Jul 2017 14:29:08 +0000 So I think for my use case I will use the x, y and z end stop pins.

I am not looking for full brightness. I just want to have color change states for the following:

-Bed has reached target temp
-Nozzle has reached target temp (so I can switch out filaments)
-first layer is complete ( I always stick around until the 1st layer is down)
-Nozzle temp has cooled down below 65C
-Bed has cooled down below 30C ( I often print objects that will take two sessions to print all the required parts)

LEDs strips are 12V, the rambo is 5V. I may also go the route of using the cheap 2 pin diode RGBs or maybe the a single 4 pin all in one RGB.

I should use a mosfet to be super safe but would it be risky to do the following?
- Use a single led for each color.
- use a standard 3 wire servo bundle with a large limiting resistor inline to each of the LEDs

On another note, if Prusa could offer such a kit I would probably buy it (even though shipping would tack on $40 to the final price) because for me time is always the resource I am short of. Would so cool if you could get the MM kit completely built from the factory for this same reason.

Thanks for any feedback or thoughts,
Dave]]> Others (Archive) david.b14 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-37222 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-37146 Thu, 13 Jul 2017 17:14:19 +0000 The more I think about it, the more I think I'm just going go down the ultra simple path, and just hook white LED's to the power supply. My main interest is in visibility, not notification (although that is cool). I also turn off my machine when not in use, so the light's wouldn't be on all the time anyway, just when I'm using it. I know not everyone does this, and so I can appreciate wanting to have the extra control. But for me I think KISS will win out in this situation.

But, I still think Tom did a great job getting many of us thinking about what we can do with not too much work.]]> Others (Archive) steven.s14 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-37146 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-37135 Thu, 13 Jul 2017 15:50:11 +0000 I've been doing some research on this as well. There aren't many pins on the MiniRambo not in use that are firmware controllable (not being used as an input only). You could tap into the X Y or Z Max end stop pins since they aren't being used and these are able to be GCode driven without having to modify the firmware.

The IRF520 which Tom shows in his video will hold the primary load since you are wiring the Power for the driver directly from the power supply and the driver is acting like a relay in that it just needs to see the MiniRambo sending a signal to tell the driver how much power to allow through. I'm planing on using an RGB LED strip which means I'll need three of the IRF520 drivers and I will probably be using all three of the Max Endstop pins to do this since I don't intend (currently) to wire in a filament run out sensor (which I currently do have one from Dyze Design) since I'd rather not mess with the firmware only because if Prusa is possibly going to keep updating it I don't want to have to constantly have to re-enable the runout sensor and its pin and reflash the board.]]> Others (Archive) Jeepguy42 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-37135 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-37045 Wed, 12 Jul 2017 03:47:57 +0000




These map to port P3 as shown below:


Full size image: http://reprap.org/mediawiki/images/e/ef/MiniRambo1.3a-schematic-pg2.svg

The question is are these pins GCODE enabled in the stock MK2 firmware?]]> Others (Archive) david.b14 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-37045 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-36891 Mon, 10 Jul 2017 13:14:57 +0000 http://chaozlabs.blogspot.de/2015/08/esp8266-in-wild-wifi-led-controller-hack.html) for around $12.

For $12 dollars you get a ESP8266 with 5 mosfets for driving LEDs. You can have Red, Green, Blue, warm white and cool white.

]]> Others (Archive) david.b14 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-36891 https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-36880 Mon, 10 Jul 2017 09:07:46 +0000 So, If I understand you correctly, utilizing all you plan to. The only controllable pins left are the X-max (30), and P3 pin 9 (not sure on arduino call out), and possibly Z-max (23). Is that correct? While I doubt I2C is in my future (but you never know), I do think for myself leaving openings for Multi-material upgrade and Filament runout sensor are good ideas. So far (only a few weeks old), I haven't seen the need for a Z-endstop either in synchronizing motor position , or in concern for height, but I'm still very green, so that may be another usable pin for myself.

I think like many of us, after seeing Tom's video on adding lights this weekend, it does seem like something to look into. Hi Steven,

You can use all listed pins as you like, it is up to you. But i think it makes really sense not to use the MM used pins.
I just colored some in because of MY plannings to do.
If you check the schematics you will see that P3 pin 9 is RESET and already used in several different locations like P2 pin 8.]]> Others (Archive) 3d-gussner https://forum.prusa3d.com/forum/original-prusa-i3-mk2-s-others-archive/mk2-rambo-pin-available-for-led-control-w-gcode/#post-36880