I just finished the assembly of my Eleksmaker A3 laser engraver (2.5W). These are some notes for personal reference (I use Linux). Perhaps you find some useful information too.

• Hardware
  • Mana SE board
    • Safety improvement (laser pull down resistor)
• Firmware
  • Flashing new firmware
    • Pre-built images
    • Custom-build, using Arduino IDE
• Testing the connection
• Settings
  • Testing the laser
    • Focus the laser
• Modding
• Tools
• References

The Laser is connected to pin Arduino pin D11 (both configured in GRBL firmware and wired on Mana SE board).

As others pointed out, to avoid an uncontrolled laser-flash on power-on, it is advised to add a pull-down resistor (1K to 2K):

The mana se board uses an Arduino Nano as MCU. So it's easy to update/change the firmware with e.g. the Arduino IDE.

I successfully used the GRBL v1.1f.20170701 version.

Flash firmware using avrdude, e.g.
avrdude -c arduino -b 57600 -P /dev/ttyUSB0 -p atmega328p -vv -U flash:w:grbl_v1.1f.20170801.hex

Download sources from https://github.com/gnea/grbl, install to ~/Arduino/libraries and open grblUploader example sketch in the Arduino IDE afterwards. Compile & upload.

Start serial terminal connection with screen /dev/ttyUSB0 115200. Then you have an interactive session with the GRBL firmware. Note that local echo is off, i.e. you don't see what you enter. Commands typed in are in <<CMD>> brackets. Example session:

$ screen /dev/ttyUSB0 115200
<<CTRL+X + ENTER>>
Grbl 1.1f ['$' for help]
<<$ + ENTER>>
[HLP:$$ $# $G $I $N $x=val $Nx=line $J=line $SLP $C $X $H ~ ! ? ctrl-x]

(Quit screen with CTRL+A+\)

According to http://wiki.eleksmaker.com/doku.php?id=eleksrom, the default settings are

• step mm 80 ($100,$101, $102)
• acceleration 200 ($120,$121, $122)
• Laser mode on ($32)

Read settings with command $$ (see previous chapter).

<<$$ + ENTER>>
ok
$0=10
$1=25
$2=0
$3=0
$4=0
$5=0
$6=0
$10=1
$11=0.010
$12=0.002
$13=0
$20=0
$21=0
$22=0
$23=0
$24=25.000
$25=500.000
$26=250
$27=1.000
$30=255
$31=0
$32=1
$100=80.000
$101=80.000
$102=80.000
$110=1000.000
$111=1000.000
$112=10000.000
$120=200.000
$121=200.000
$122=200.000
$130=200.000
$131=200.000
$132=200.000
ok

Note: if not already done, put the protection glasses on now. And also make sure there are no nearbys smoke alarms ;)

To Turn laser on and off (make sure the weak light button is not pressed):

M3     ; constant laser power mode
$32=0  ; Laser mode off
S255   ; 255 = FULL POWER ;)
S0     ; OFF

M3 enables constant laser power mode. $S32=0 turns the laser mode off, so S255 has immedeate effect. Otherwise, when in laser mode ($32=1), the laser will only be on during movements. Afterwards send a S0 to turn the laser off again.

Use the weak light button and the focus wheel on the laser module to focus the laser.

• Marco Reps: https://www.youtube.com/watch?v=ZzO9skEYqwY / https://reps.cc/?p=5

• Universal Gcode Sender
• LaserWeb

• Grbl settings 101 - a how to guide
• Grbl v1.1 Configuration