GRBL CNC Controller

Name: GRBL CNC Controller
Author: kerry

4.4

Secure

kerry

10K+ installs

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CNC Mobile Control for GRBL (USB)

GRBL CNC Controller: USB OTG control for GRBL CNC machines

By Priya Raghavan

Senior reviews editor

USB OTG link to a GRBL controller with a selectable baud rate
Live X, Y and Z work position readout
XY jog pad, Z buttons and adjustable jog step and speed
Spindle on/off and spindle speed control
Terminal for sending custom GRBL commands and reading replies
Open .nc and .gcode files, then play, stop and track job status

What the app is for

GRBL CNC Controller runs on an Android device and talks to an Arduino-based machine running GRBL firmware. The phone or tablet plugs into the machine's controller through a USB OTG cable, so no computer is needed in between.

The app is aimed at people who run a GRBL CNC and want to operate it from a handheld device at the machine. Its screen covers the usual hands-on tasks: reading position, setting zero, moving the axes, switching the spindle and running a program.

Connecting and reading machine position

The connection is made over USB OTG, and you pick the baud rate that matches the controller. Once connected, the app shows the work position for X, Y and Z in real time.

Reset, Unlock and Home are available as direct controls for recovering from alarms and referencing the machine. A GRBL terminal, labelled Term, lets you send your own commands and see the controller's responses.

Setting work zero and jogging the axes

Dedicated X0, Y0 and Z0 buttons set the current position as zero for each axis. A Go XY/Z Zero command returns the tool to those zero points.

Movement comes from an XY jog pad and separate Z-axis buttons. Jog step size and jog speed can both be adjusted, so the same controls work for fine positioning and faster travel.

Spindle control and running G-code files

Spindle control lets you turn the spindle on or off and set its speed from the same screen as the axis controls. The app does not require a separate panel for the spindle.

G-code files with .nc or .gcode extensions open directly in the app. Play and Stop start and halt the job, and a status line shows where the file stands. A live feedrate override changes job speed by plus or minus 10 percent while the program is running.

What's new

May 25, 2026

🔌 USB CNC Connection — Direct control of your GRBL machine
📄 G-code Sender — Load and run G-code files with progress tracking
🎮 Jog Control — Manual XYZ axis movement with variable speed
📍 Live Position Display — Real-time X, Y, Z coordinates & machine status
🤖 Auto Error Recovery — Bad lines skip automatically, job continues

About this APK

The build we hold is GRBL CNC Controller 4.4 (APKS split bundle) for Android 10 and up.

Version: 4.4; 7
Requires Android: 10+

Package ID: com.kerry.grblcontroller
Format: APKS split bundle
Malware scan: Clean on 65 engines
Permissions: 6 declared
Signed by: CN=Android, O=Google Inc.
Certificate SHA-256: 35c1ad5d31adca829c688064ecb2fe406806a04ebc00a2a9ef4851873abf37bb