How to send G-code from an Android phone to a GRBL laser
You can send G-code from an Android phone to a GRBL laser engraver with a USB OTG adapter and a data cable, over Bluetooth if the laser has a Bluetooth module, or over WiFi if it has a network connection. A G-code sender app such as CNC Laser Pro - Engrave & Cut opens the connection, streams the G-code line by line and shows the machine state while it runs.
What you need
| Connection | You need | Good for |
|---|---|---|
| USB serial | USB OTG adapter (or USB-C cable) and a data cable | Most hobby lasers; the most reliable link |
| Bluetooth | A laser with a Bluetooth serial module, paired in Android settings first | No cable across the workshop |
| WiFi TCP | A laser on your network (or its own hotspot) and its IP address | Lasers with WiFi controllers such as FluidNC |
| WiFi FTP | A controller with an FTP server | Uploading a file to run from the controller |
Send a job step by step
- Create the job in the app (photo, design, vector or text) and check the burn preview.
- Open Transfer and choose the connection type: RS-232 (USB), Bluetooth, WiFi TCP or WiFi FTP.
- Tap Connect. On GRBL the app shows the machine state and position.
- Set the work zero with the jog controls, or use the frame function to check where the job lands.
- Tap Send. Keep the app open and the screen on until the job is done.
If the app is interrupted (a call, the screen locks, another app opens), CNC Laser Pro pauses the machine. Resume continues from where it stopped. On WiFi, Android may close the connection after a few seconds in the background; the machine stays paused and that job cannot be continued.
Machine not found over USB
- The OTG adapter is connected and OTG is turned on in the phone settings. Some phones turn it off after a few minutes.
- The cable carries data. Many short cables only charge.
- The laser is powered on.
Bluetooth permission denied
Android needs the Location and Nearby devices permissions to search for Bluetooth devices. If you denied them, open the app settings, tap Permissions and allow both. The app does not use or store your location.
Which lasers this works with
Any GRBL-based laser engraver, for example from Ortur, Atomstack, Sculpfun, Creality, Two Trees, Comgrow, Longer, Mecpow, Acmer, Eleksmaker and xTool D1. Tested on Creality Falcon, Sculpfun C1, Acmer S1 and Mecpow X3. See supported machines.
Before the first real job, run a small test at minimum power. Wear laser safety glasses and never leave the laser running alone.
Related: supported machines, GRBL error and alarm codes.