Pen not always going the whole way down


My Line-us seems to be occasionally getting stuck when trying to put the pen down. It would appear that the cam has rotated to the correct position but the body of the robot doesn’t always seem to follow along. From what I can gather, either:

  • The springs are starting to lose their force
  • It needs some lubrication inside of the shafts

Please help! I love this lil guy.


Looks like your Line-us needs a bit of lubrication as you say - I’m guessing you’ve been using your Line-us a lot, which is great!

I’ve just put together a quick post in the FAQ on how to do it and it should get you back in action.

Let us know if you have any questions or if there’s anything that’s not clear in the post.


Thanks Rob! A quick test with my Line-us after applying some silicone lubricant and that seems to have done the trick. I’m using my Line-us programatically with JS so I’m definitely putting it through its paces compared to the average user. :slight_smile:


Nice! Not sure whether you’re aware but we now have Websockets support (firmware 2.0.4, which is now the released version). Just update firmware from the app or send M997 if you’re interested. Only thing to be aware of is not to power off Line-us during the update.


Ah great! I’ll have to give it a go at some point. Is there any documentation?


Not yet - same commands as the socket interface and this should get you started…

<!DOCTYPE html>
<html lang="en">
<p id="output"></p>

    var lineUsName = prompt("Please enter the name of your Line-us.\n\nIf you're not sure just click OK to accept the default name.", "line-us.local");
    const socket = new WebSocket('ws://' + lineUsName);
    socket.addEventListener('open', function (event) {
    socket.addEventListener('message', messageHandler)

    function messageHandler(event) {
        document.getElementById("output").innerHTML += ( + "<br>");
        if(, 2) == "ok") {