GRBLDroidBT is a CNC Controller that works with the grbl 0.9+ firmware.
It does not work with the GRBL 0.8 or GRBL 1.1 firmware.
It is the Bluetooth version of the normal GRBLDroid.

Using a Bluetooth Android tablet you can pilot your grbl CNC machine via wireless.
GRBL is the most common firmware used in the open source community for CNC machines.
With GRBLDroidBT you can send commands, jog the CNC machine and send g-code files using two methods simple and advanced.

Please read the official online documentation on how to connect via Bluetooth the tablet with the Arduino board.
Official Documentation link :
http://www.trustfm.net/software/mobile/GRBLDroidBT.php?page=Documentation

Prerequisites
In order to use GRBLDroidBT you need :
1) A CNC machine
2) An Arduino Duemillanove / UNO board
3) An HC 05 Bluetooth module
4) An CNC SHIELD
5) 4pcs A4988 StepStick stepper drivers
6) One 1K resistor and one 1.8K or 2K resistor
7) Some Jumper wires
8) An Android tablet with Bluetooth

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1) GRBLDroidBT will work only with GRBL 0.9+ versions

2) GRBLDroidBT supports simple and advanced file mode.
I have followed the official instructions from here :
https://github.com/grbl/grbl/wiki/Interfacing-with-Grbl

The simple mode is as described here :
Streaming Protocol: Simple Send-Response [Recommended for Grbl v0.9+]

And the advanced mode is as described here :
Streaming Protocol: Character-Counting [Recommended with Reservations]

3) GRBLDroidBT checks if the commands are 80 lines long (including the last enter char)

4) At least the "simple" streaming mode should work .


Official site link :
http://www.trustfm.net/software/mobile/GRBLDroidBT.php

Official Documentation :
http://www.trustfm.net/software/mobile/GRBLDroidBT.php?page=Documentation