felipe_r

Hello, I've been developing a robotic arm able to take the printing out of a 3d Printer once the process is finished, being the reason that the lab i'm doing services for wants to automatize the process of finishing a print/starting the next print (if any) when no one is on the lab. I tested this arm with a UM2 machine + A Ramps 1.4 Processor/Arduino Mega in Lab's possession and it works fine, controlling it via I2C and using gcode (M260). The issue I face now is that at the end, the printers used by the lab are UM3 Extended. I've become aware more and more of the differences in Hardware architecture between UM2 and UM3 Extended (should have done this before, yes I know), and the tutorials posted here helped me a lot to see where the I2C ports are in the UM3 Extended. Considering that both I2C-based cables, P2 and P5 in the schematic here, are not connected to anything (not sure if i understood well, but those connections went to what was called "Feature X?" here), I had the idea of using one of these two unused cables to send I2C commands. Before trying anything with the UM3, I got into the UM3 developer mode and connected via Putty/SSH. Using ultimaker as user, i managed to enter the command interface and used G28 and G0/G1 successfully + still not connecting my mechanical arm, used M260, getting a message that the command was sent. Then I connected the arm to one I2C port of the 3d printer, checking several times that the pins were well connected in order to not burn the UM3 Extended, but I could not move the arm. With a logic analyzer, could see that connections were alright since i'm receiving the data sent to the print head with the right I2C addresses, the clock, 5V and GND properly, but when a message is sent via M260 using the command interface, nothing is received by my arm Microcontroller, so in at least one part of the process the message is being lost. I've been reading different posts in this forum and saw that the M260 is not listed amongst the possible commands to use, but G28 is not listed either and still I could use it. Also, I have seen nothing like the "I2C_EXPERIMENTAL" in a couple of Marlin Firmware versions (2017.06.21 and 2016.10.10) for the Ultimainboard. Finally, I have not found much references to the I2C port inside griffin folder. Is there a not too difficult way to control a slave (like my mechanical arm) via I2C, with the Ultimainboard as a master? I'm aware of the danger related to the usage of the developer mode and the addition of electrical connections to the I2C port of the UM3. PS: I would have liked to utilize the server, but the lab is using 3dprinterOS and I could not send commands through its platform. The firmware the UM3 Extended has is: 5.2.11.20190503. Cheers and thanks in advance!