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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Error opening serial port /dev/ttyACM0: Port not found","articleBody":"I'm running a fresh install of Ubuntu 25.04 on a RaspberryPi4B with Processing 4.4.4. I cannot get the serial ports to work.  Here is a simple sketch:\n\n```\nimport processing.serial.*;\nSerial myPort;\n\nvoid setup()\n{\n  println(Serial.list());\n  String portName = Serial.list()[0];\n  println(portName);\n  myPort = new Serial(this, portName, 9600);\n}\n\nvoid draw()\n{\n}\n```\nSerial.list() appears to work correctly.\nConsole output:\n```\n/dev/ttyACM0\n/dev/ttyACM0\n```\nI also get the red banner error code:\n`Error opening serial port /dev/ttyACM0: Port not found`\n\nI thought it might have something to do with permissions:\n```\n$ ls -l /dev/ttyACM0\ncrw-rw-rw- 1 root dialout 166, 0 May 24 11:52 /dev/ttyACM0\n```\nI am in both the `dialout` and the `tty` group.\n```\n$ groups budryerson\nbudryerson : budryerson adm tty dialout cdrom sudo dip plugdev users lpadmin\n```\n\nI've been beating my head against this for days, and I'm not getting anywhere. I turn to you, my friends, for help. Does anybody have any ideas?\n\nThanks,\nBud Ryerson\nSan Francisco\n\n\n\n\n\n","author":{"url":"https://github.com/budryerson","@type":"Person","name":"budryerson"},"datePublished":"2025-05-24T21:00:46.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/1119/processing4/issues/1119"}