Mechanica Firmware – Horus (ZUM Scan)

Horus 3D scanning banner



Informatie (ENG):

The Horus firmware is a program that allows you to control the stepper motors, laser modules and LDR analog sensors using G-code commands. It is compatible with Arduino based boards and the ZUM SCAN shield.

The firmware has been designed to control all physical elements of the Ciclop 3D scanner, a rotating scanner based on laser triangulation. The base of the code is the Grbl project, a program that enables CNC machines to be controlled. It has also been used in other projects such as Marlin, the firmware for 3D printers.

This firmware is written in C. ,Derived from Grbl v0.9 by Jesús Arroyo (Mundo Reader S.L.)
Grbl’s lead developer is Simen Svale Skogsrud. Sonney Jeon (Chamnit) improved some parts of grbl.


  • Angular stepper motor movement
  • Interrupt based movement with real angular acceleration
  • Laser modules control
  • Analog sensor read
  • Configuration interface with $ commands

The default baudrate is 115200.

Implemented G Codes

  • G1 – Angular movement
  • G50 – Reset all positions to zero
  • M0 – Program pause
  • M2 – Program end and reset
  • M17 – Enable/Power stepper motor
  • M18 – Disable stepper motor
  • M50 – Read LDR
  • M70 – Laser off
  • M71 – Laser on


Open horus-fw.ino, select your board and upload.


The binary horus-fw.hex can be flashed with Horus GUI.


You can communicate with the board via USB or Bluetooth. There are different open source applications for establishing the connection, such as the Arduino Serial Monitor or CuteCom10. If the latter is used, you will need to select the device, adjust the baud rate to 115200 and set the command ending to LF  or CR,  ‘\n’ or ‘\r\n’, respectively.

After starting the serial communication, this will be the first message that Horus sends:

Horus 0.1 [‘$’ for help]

After each command is received, the software will answer with ok when the processing of that command ends, either correctly or with an error  message. The communication flow is as follows:

arduino serial cutecom


The Horus firmware, due to its Grbl heritage, provides a configuring and monitoring interface which uses $ commands, as well as control commands in real time. All supported commands are described in the Grbl wiki.

Yu can also view the help menu on the available configuration commands by sending $:

As an example, the commands $110=v y $120=a, adjust the speed and maximum acceleration of the motors to v º/s and a º/s² respectively.

G-code commands

G-code is the most widely used programming language in numerical control devices (CNC). Milling machines, laser cutters and 3D printers use this de facto standard to communicate. Instructions are executed sequentially in this language. These are the G-code commands that have been integrated into Horus:

G1: Circular movement

G1 Fv  Adjusts the rotational speed to v degrees per second
G1 Xd  Moves the stepper motor to the position d defined in degrees

M0–M2: Pause and program end

M0  Pauses the program. It may only be restarted through the Cycle start (~) command
M2  Stops the program and resets it

M17–M18: Enable / Disable the stepper motors

M17  Enables the motors, maintaining their position. They stay enabled even after sending G1 commands
M18  Disables the stepper motors. They stay disabled even after sending G1 commands.

M50: LDR analog sensors reading

M50 Tv  Reads the LDR sensor connected to pin v. Returns an integer between 0 and 1023

M70–M71: Laser modules turn on / off

M70 Tv  Turns off the laser module v
M71 Tv  Turns on the laser module v. After a four-minute timeout, the laser is turned off automatically

Download Horus firmware @ Github