RapiLaser › Engrave from an Android phone
Engrave with your laser from an Android phone, no computer
Yes, you can: a diode laser engraver running GRBL 1.1 firmware can be controlled from an Android phone with Chrome and an OTG data cable, with no computer and nothing to install. RapiLaser opens in the browser, talks to the machine over USB and sends the job from the phone itself. You can design on your laptop and engrave from the phone, or do everything on the phone.
What you need:
- An Android phone or tablet with Chrome (or Edge). Android is where it works: on iPhone and iPad you cannot connect the machine, because Safari does not let a web page talk over USB.
- An OTG data cable from the phone to the machine. It is failure number one: many cables and OTG adapters only charge and do not carry data, they look identical and cost less. With one of those the port list comes up empty and no error explains why.
- A machine with GRBL 1.1 or compatible firmware: Atomstack, Sculpfun, Ortur, Creality Falcon, TwoTrees, Longer, NEJE and most diode engravers. The list is on compatible machines.
How to connect, step by step
- Turn the machine on and plug in the OTG cable: one end in the phone, the other in the machine's USB port.
- Open app.rapilaser.com in Chrome and sign in with your code (the 30-day trial license is free and asks for no card).
- Tap the green plug, “Connect”. Android asks whether the page may use the USB device: accept and pick your machine.
- RapiLaser identifies the machine, checks its settings and warns you if the head may move to the corner by itself on connecting. From there, frame, focus and tap Start.
If something does not work, the Diagnostic is public and free: it asks for no account or code, connects to your machine and tells you what your browser supports and which firmware the machine runs. It is the way to know, before paying, whether your phone and your cable will do.
What works and what does not
- Yes: designing on the phone (shapes, text, dithered images, vectorizing a logo), generating the G-code on the phone itself and controlling the machine: connect, frame, start, pause and the STOP, which is always in view.
- Yes: designing on the computer and engraving from the phone. Save the project as a .rpl file, move it to the phone and open it in RapiLaser; projects saved “in the browser” stay on the device where you saved them.
- Do not switch apps or lock the screen while it engraves: Android throttles background tabs and the job would stop. Keep the phone plugged in or charged for the whole piece.
- It does not work over WiFi or Bluetooth: the connection is always by cable. And it does not work on iPhone or iPad.
- Newer xTool models and LaserPecker do not work, as they use a closed protocol, nor do CO2 machines with Ruida or DSP controllers.
Why it works on Android and not on iPhone
RapiLaser is not an app from a store: it is a web page. On a computer, Chrome and Edge let a page talk to a serial port (Web Serial); on Android, Chrome lets it talk to a USB device (WebUSB), and that is how RapiLaser sends the G-code to the machine's GRBL board, line by line, just like from a computer. Safari, on iPhone and iPad, has neither. So on an iPhone you can use the editor, but not connect the machine.
All the computing —the design, the G-code, the image dithering and the sending to the machine— happens on the phone. No G-code travels over the internet, and the machine keeps working even if the network drops.
Frequently asked questions
Do I need to install an app on the phone?
No. RapiLaser opens in Chrome and nothing is installed. If you like, Chrome lets you add it to the home screen as if it were an app, but it is still the same page.
Which OTG cable works?
A data cable, not a charge-only one. If the phone has USB-C, a USB-C to USB-B cable (the square connector on the machine) or an OTG data adapter plus the cable that came with the machine. If the port list is empty when you connect, the cable is the first thing to change.
Can I design on the laptop and engrave from the phone?
Yes. Save the project as a .rpl file on the computer, move it to the phone (by email, WhatsApp or cable) and open it in RapiLaser from Chrome. The design arrives whole, with its layers and settings.
Does it work on an Android tablet?
Yes, the same as on a phone: Chrome and an OTG data cable. The bigger screen helps for designing.
What about iPhone or iPad?
You can open RapiLaser and use the editor, but not connect the machine: Safari does not let a web page talk over USB. To engrave you need an Android device or a computer with Chrome or Edge.