Using gSender


Here’s a great video that goes over much of how a G-Code sender works in the context of gSender. See Kelly explain many of its uses and features:


You can connect to your CNC machine by hovering over “Connect to Machine” at the top left corner, and pressing the COM port you wish to connect to. Sometimes there’s more than one COM port available, so you may need to try both to see which one your machine is connected to.

Once you have selected the COM port, your machine should be connected. You will see the ‘plug’ icon turn green, the status on the top right corner of the visualizer change to “Idle,” and the controls activate, allowing you to press them.

If you are not seeing those changes when you connect, please check the following:

  1. Arduino is securely attached to the LongBoard.
  2. Any other programs that can talk to the Arduino are closed (ex. Arduino IDE, Easel, UGS).
  3. See if you have other COM ports available, and try to connect to them.

Jogging and Presets

You can move the machine by using the Jog Control, through the arrow buttons. Change the “XY move” and “Z move” to adjust the distance you travel per click. You can also change  “Speed,” which determines how fast the machine will move when jogging. The “Rapid,” “Normal,” and “Precise” buttons will allow you to toggle to different distance and speed values quickly. You can change the values to what works for you, by going to the ‘gear’ and editing the “Jogging Presets” in the “General” section of the settings.

Manual Zero and Gotos

Each g-code file will have a starting position in which the coordinates of the toolpaths reference off of. This is the zero or origin. There are two ways to manually set your zero on gSender.

  1. To set the zero for each individual axis one at a time, you can use “Zero X,” “Zero Y,” and “Zero Z.”
  2. To set the zeros all at once, use “Zero All.”

The large blue numbers at the readout indicate the current position of your machine. If you wish to return to your zero position, you can press the “Go to” for each axis or “Go to XYZ0.” You should see the large blue numbers read “0.00” once you have returned to your zero.

You can reset your zeros anytime when the machine is not actively running a job. The machine will remember your zero if you stay connected on gSender and if you do not move the machine position by hand. If you turn the lead screw with your fingers or push the gantry, the machine does not know you have moved it, therefore you will lose your zero position.  You can jog on the Jog Control without losing your zero position, because gSender knows you are moving the machine.


The probe allows us to automatically set a zero position, usually at the bottom left corner of the stock material, using a touch plate. Before we can run the touch probe for the first time, we need to check that the probe settings are correct and that the end mill sizes in the “Tools”
section match what you have. You can add different end mills by entering the diameter in millimetres or inches, and then pressing “Add Tool”.

Once you have set up the touch plate, banana plug and magnet on the machine, you can choose which axis to probe for, and the diameter of the bit you are using if applicable. Jog the machine so that the bit is hovering over the Sienci Labs logo on the touch plate. Then press “Probe”.

Before the process begins, there is a conductivity test to ensure that the touch plate components can conduct electricity, which allows a signal to be sent to the LongBoard when there is contact. You can either bring the touch plate to the end mill or touch the banana plug and magnet together. Make contact a few times just to confirm there is conductivity, as the red circle should flicker to green.

A blue button called “Start Probe” will appear if you have successfully confirmed conductivity. Ensure that the touch plate components are set up for probing, then press “Start Probe.” The machine will move to probe three sides of the touch plate, twice on each side. There should not be any crashing or abrupt movement. Once the process is over, remove the touch plate components from the machine and then press “Go to XYZ0.” The bit should be just touching the top of the stock material, positioned at the bottom left corner.

Running Jobs

If you have already prepared a project file, ensure the following:

  1. The file is an .nc or .gcode file.
  2. The file is exported to the correct post processor for the LongMill. Please see this page for the correct post processor for your CAM software:

To run your project on gSender, press the “Load File” button. A dialog box should pop up, where you can navigate to where your file is.

Double click on the file, and the project should be shown on the Visualizer, along with information such as the dimensions and estimated time.

You can run “Test Job” which enables gSender to go through your g-code to look for potential errors or unknown commands, without running it on the machine yet.

Once your machine is ready with your router and vacuum on, press “Start Job” to begin your cut. You can pause and stop your job at any time with the respective buttons. If you press “Pause Job”, you can resume the job from where you left off. Otherwise, “Stop Job” will cancel your job completely.

At the bottom of the screen, a progress bar shows how many lines of g-code have been processed and how many are left. Additionally, you can adjust the feed rate and spindle speed by pressing the ‘plus’ and ‘minus’ buttons to override what you have set in your g-code.