The Switch module takes care of basic input from things like buttons and switches and controls simple devices like fans and pumps.
It is an incredibly versatile tool that allows you to setup a lot of on-off type systems. It listens to input pins and outputs custom G/M-codes or accepts custom G/M-codes and set outputs to GPIO pins.
This allows you to do one of the following:
You can create several different switch modules to fit your needs, within the same configuration file.
If you come from the industry, the Switch module is Smoothie’s implementation of a Programmable Logic Controller feature.
Like TemperatureControl, there can be multiple Switch modules. All you need to do is give each module its own name in the config file.
switch.fan1.enable true
switch.fan1.output_pin 2.7
etc ...
switch.fan2.enable true
switch.fan2.output_pin 2.6
etc ...
switch.zplus10.enable true
switch.zplus10.input_pin 1.7
switch.zplus10.output_on_command G91G0Z10G90 # G90 and G91 switch to relative positioning then back to absolute
etc ...
| Option | Example value | Explanation | | —— | ————- | ———– |
| Parameter | Default | Description |
|---|---|---|
switch.module_name.enable |
true | Create and enable a new Switch module if set to true. Switch modules use commands or pins as inputs, to send commands or switch pins as output. Note this module is very versatile and can be used to do many different things. Parameters that are not defined will be ignored. |
switch.module_name.input_pin |
2.11 |
When this pin becomes high the switch changes to the ON state, and when it becomes low the switch changes to the OFF state. ( see the input_pin_behavior option for more details ) |
switch.module_name.input_pin_behavior |
momentary | If set to momentary when the input pin becomes high the switch changes to the ON state, and when it becomes low the switch changes to the OFF state. If set to toggle the input pin toggles the switch’s state between ON and OFF. |
switch.module_name.input_on_command |
M106 | Calling this command sets the switch ON |
switch.module_name.input_off_command |
M107 | Calling this command sets the switch OFF |
switch.module_name.subcode |
1 | the subcode that the input on or input off commands respond to M106.1 |
switch.module_name.output_on_command |
abort | This command is called when the switch changes to the ON state |
switch.module_name.output_off_command |
resume | This command is called when the switch changes to the OFF state |
switch.module_name.output_pin |
2.6 |
This pin will be set low when the switch is OFF, and high when the switch is ON |
switch.module_name.output_type |
pwm | Sets the type of output for the output_pin, if set to digital the pin can only be low or high, and if set to pwm the pin can be set to any Sigma-Delta PWM value between 0 and 255 using the S parameter, for example : M106 S127. If set to hwpwm will use Real PWM, but the selected output pin must be PWM capable. The S value will be the duty cycle in percent, NOTE the default is none which will disable the output entirely. Can also be set to swpmw for software-emulated ( non-hardware ) pwm, that will be slower, but will not interfere with hardware pwm peripherals like a laser module. |
switch.module_name.startup_state |
false | Startup state of the switch. If set to false the module is initialized OFF, if set to true the module is initialized ON |
switch.module_name.startup_value |
184 | Startup value of the switch if the output_type is any kind of pwm. startup_state must be false for this to take effect. It is also the value the hwpwm or swpwm is set to on HALT. |
switch.module_name.default_on_value |
184 | Default on setting value of the switch if the output_type is swpwm or hwpwm. It is also the value the hwpwm or swpwm is set to when startup_state is true |
switch.module_name.max_pwm |
210 | Maximum value for the PWM output. (only used for pwm output type, not for hwpwm) |
switch.module_name.pwm_period_ms |
20 | Period used by the H/W and S/W PWM, 20ms is 50Hz which is the default if not set |
switch.module_name.failsafe_set_to |
0 | 0 or 1 what to set the output pin to in case of a crash or HALT condition |
switch.module_name.ignore_on_halt |
false | set to true to not set the failsafe or startup_value value when a HALT condition is triggered |
The initial internal state of the switch at boot is set by the startup_state setting, which should be set to “true” or “false”.
Also remember that individual pins can be inverted with a ! ( see Pin Configuration ). Default is false.
There is also a startup_value setting that sets the default analog value used for pwm on an output pin. This value defaults to always on.
switch.fan1.startup_state false
switch.fan1.startup_value 127
NOTE a switch can have either an input pin defined or an output pin but not both. If for some reason you needed an input pin to control one or more output pins you could define two (or more) switches, one input and one or more outputs. Then the input pin would define the M-codes that turn on/off the output pins in its output_on_command (and/or its output_off_command).
This setting will enable a pin that can be used to change the state of the switch. For example, a button can be configured that toggles the state of a fan. By default input_pin is set to “nc” which stands for “not connected”.
There is also a behavior setting for the input pin. Currently the valid options are momentary (default) and toggle.
The toggle behavior allows a momentary button to behave like an on-off toggle switch. If you are connecting a physical toggle switch you would probably want the behavior set to momentary.
switch.fan1.input_pin 1.7!
switch.fan1.input_pin_behavior toggle
Set this config value to drive an output pin based on the internal state of the Switch module. Remember that the pin can always be inverted with a ! ( see Pin Configuration ).
switch.fan1.output_pin 2.7
switch.fan1.output_type pwm # pwm output settable with S parameter on the on command
switch.fan1.max_pwm 255 # sets the max pwm for this pin
To set an output pin to be non-pwm so it just turns on or off set output_type digital
switch.psu.output_type digital # just on or off
switch.psu.output_pin 1.30o! # set to open drain, inverted to control an ATX PSON signal
There are four different output types: digital, pwm, swpwm and hwpwm, the default is none so no output pin is configured.
(The names MUST be lower case)
Note that pwm is actually SigmaDelta Modulation and will allow you to set PWM intensity via the S parameter to your G-codes, values between 0 and max_pwm are accepted, which is usually 255.
hwpwm is PWM controlled by the Hardware, and is PWM compatible with Hobby servos/bltouch and ESCs. The S parameter specifies the duty cycle in percent, and for a typical servo will be between 5% and 10% (1ms to 2ms when running at 50Hz) for a 180° turn. the default frequency is 50Hz but can be set with the pwm_period_ms config setting.
swpwm is PWM emulated by the software, and is PWM compatible with Hobby servos/bltouch and ESCs. And is otherwise similar to hwpwm. This is useful if your hwpwm clock must be set to a very high value for example for the laser module, as this would mean a hwpwm switch would need to have the same high value which can be incompatible with some hardware. Having a lower frequency swpwm allows for both the laser module and servos/bltouch control.
There are also a set of config settings that allow the Switch module to both generate and react to Gcodes as necessary. The input_on_command is also able to read an S parameter to set an analog value for pwm over the output pin. This allows things like driving a fan at less than full speed or dimming an led.
switch.fan1.input_on_command M106 # any command that starts with this exact string turns this switch on
switch.fan1.input_off_command M107 # any command starting with this exact string turns off the switch
In addition to input_on_command and input_off_command there are also corresponding config settings output_on_command and output_off_command. Offhand, it seems unlikely that a single switch module would need to use both input_ and output_ commands.
[!NOTE] If you want to learn more about this module, or are curious how it works, Smoothie is Open-Source and you can simply go look at the code, here.
This configuration will allow you to control a fan using the standard reprap G-codes for controlling a fan
This is already present in the default configuration file
# Switch module for fan control
switch.fan.enable true # Enable this module
switch.fan.input_on_command M106 # This switch is turned on when M106 is sent
switch.fan.input_off_command M107 # This switch is turned off when M107 is sent
switch.fan.output_pin 2.6 # This pin is turned on when this switch is turned on, and vice-versa
switch.fan.output_type pwm # PWM output settable with S parameter in the input_on_comand
#switch.fan.max_pwm 255 # Set max PWM for the pin default is 255
This configuration will allow you to control a servo using the standard reprap G-codes for controlling a servo.
M280 S5 would be fully to the left and M280 S10 would be fully to the right.
# Switch module for servo control using S/W PWM
switch.servo.enable true # Enable this module
switch.servo.input_on_command M280 # M280 S7.5 would be midway
switch.servo.input_off_command M281 # Same as M280 S0 0% duty cycle, effectively off
switch.servo.output_pin 3.25 # May be any spare pin
switch.servo.output_type swpwm # Software pwm output settable with S parameter in the input_on_command
#switch.servo.pwm_period_ms 20 # set period to 20ms (50Hz) default is 50Hz
#switch.servo.startup_state false # false uses startup_value on boot true uses default_on_value
#switch.servo.startup_value 7.43 # On boot and HALT it will set this PWM value
#switch.servo.default_on_value 3.3 # This PWM value will be set if M280 doe snot have an S parameter, it is also the value used if startup_state is true
# Switch module for a second servo control using H/W PWM
switch.servo2.enable true # Enable this module
switch.servo2.input_on_command M280 # M280.1 S7.5 would be midway
switch.servo2.input_off_command M281 # Same as M280.1 S0 0% duty cycle, effectively off
switch.servo2.subcode 1 # M280.1 will trigger this switch
switch.servo2.output_pin 3.26 # Must be a PWM capable pin
switch.servo2.output_type hwpwm # H/W pwm output settable with S parameter in the input_on_command
To find a PWM-capable pins, see Pinout
Here is how to control an ATX power supply’s ON/OFF signal from a bare pin connected to the PS_ON signal, so that your board can tell it to turn off when needed:
switch.psu.enable true # turn atx on/off
switch.psu.input_on_command M80 #
switch.psu.input_off_command M81 #
switch.psu.output_pin 0.25o! # open drain, inverted
switch.psu.output_type digital # on/off only
switch.psu.failsafe_set_to 1 # so the ATX turns off on a system crash
#switch.psu.ignore_on_halt true # so the ATX does not turn off on a HALT condition (like limit trigger)
# However leave commented or set to false if you want the ATX to turn off for an over heat fault condition
Note: this uses the PSON pin on the power supply, which should be open-drain, thus the o in 0.25o!.
Here is how to control an ATX power supply’s ON/OFF signal from a small mosfet connected to the PS_ON signal, or to an SSR which powers the non ATX PSU:
switch.psu.enable true # turn atx on/off
switch.psu.input_on_command M80 #
switch.psu.input_off_command M81 #
switch.psu.output_pin 2.4 # small mosfet (NB not inverted)
switch.psu.output_type digital # on/off only
#switch.psu.ignore_on_halt true # so the PSU does not turn off on a HALT condition (like limit trigger)
# However leave commented or set to false if you want the PSU to turn off for an over heat fault condition
This configuration allows you to use a pin to detect when the machine is out of filament. When the switch is hit by the filament not being present, the machine is put into pause.
Another switch is configured to allow you to resume the machine once the button is pressed.
Additional configuration allows you to specify commands that are executed when the machine suspends, and when it resumes.
switch.filamentout.enable true # Enable this module
switch.filamentout.input_pin 1.30^ # Pin where filament out button is connected
switch.filamentout.output_on_command suspend # Suspend command
switch.resume.enable true # Enable this module
switch.resume.input_pin 1.31^ # Pin where resume button is connected
switch.resume.output_on_command resume # Resume command
after_suspend_gcode G91_G0E-5_G0Z10_G90_G0X-50Y-50 # Gcode to run after suspend, retract then get head out of way
before_resume_gcode G91_G1E1_G90 # Gcode to run after temp is reached but before resume - do a prime
Note, there is a real filament detector module which works much better than this, see filament-detector.
This configuration allows you to set a suspend button, and a resume button.
switch.suspend.enable true # Enable this module
switch.suspend.input_pin 1.30^ # Pin where pause button is connected
switch.suspend.output_on_command suspend # Suspend command
switch.resume.enable true # Enable this module
switch.resume.input_pin 1.31^ # Pin where resume button is connected
switch.resume.output_on_command resume # Resume command
after_suspend_gcode G91_G0E-5_G0Z10_G90_G0X-50Y-50 # Gcode to run after suspend, retract then get head out of way
before_resume_gcode G91_G1E1_G90 # Gcode to run after temp is reached but before resume - do a prime
[!INFO] Stopping Smoothie
These are the different ways of stopping Smoothie:
Command G-code Movement Heaters File playing Recoverable Documentation Explanation abortM26Stops an SDCARD print immediately Not affected Aborts Position maintained, but file must be restarted Player Stops the execution of a file being played from SDCARD, it will complete the current gcode, but stop immediately after that, the rest of the queued commands are discarded. It attempts to maintain the correct position after the abort. suspendM600Stops once queue is empty Turned off if option enabled (default) Paused, can be resumed Yes, with resumeorM601, position maintainedPlayer Suspends the execution of a file being played from SDCARD or being streamed from a host (upstream support required currently pronterface and octoprint support it, otherwise host needs to be manually paused), all state is saved and jogging and extruding is allowed. Mainly used for mid print filament change, or filament out detection. M601resumes the print or theresumecommandNo command, but there is a configurable «kill» button M112Stops instantly if kill button pressed, if issued from host has to wait for the receive buffer to have room. Turned off aborted No, position is lost, home will be required supported-g-codes Instantly stops all operations, printer fully halts until M999is sent. Position is lost.Sending Control-X to smoothie over the serial port or USB serial port should work at any time even when streaming, does the same as the kill button Turned off aborted No, position is lost, home will be required Instantly stops all operations, printer fully halts until M999is sent (or$X). Position is lost.If the kill button is pressed (or there is a temperature fault,
M112is issued, a limit switch is hit or other error) the system enters the Halt state, in this state the play led flashes, and the state can be cleared by issuingM999or holding the flashing kill button for 2 seconds (it can also be cleared from the LCD panel). While in the Halt state any command issued from the host will get a!!response (with a few exceptions). The PSU may be turned off when Halt is entered if there is a psu Switch defined.All commands can be triggered by a button or a sensor if a Switch module is configured to do so.
You can read more about the kill button at Smoothie kill button
This configuration allows you to set a single button to both pause and resume the machine
switch.pause.enable true # Enable this module
switch.pause.input_pin 1.30^ # Pin where pause button is connected
switch.pause.output_on_command suspend # Suspend command
switch.pause.output_off_command resume # Resume command
switch.pause.input_pin_behavior toggle # This pin toggles between it's on and off states each time it is pressed and released
after_suspend_gcode G91_G0E-5_G0Z10_G90_G0X-50Y-50 # Gcode to run after suspend, retract then get head out of way
before_resume_gcode G91_G1E1_G90 # Gcode to run after temp is reached but before resume - do a prime
This configuration allows you to set a single button to start and stop your spindle.
switch.spindle.enable true # Enable this module
switch.spindle.input_pin 1.30^ # Pin where pause button is connected
switch.spindle.output_on_command M3 # Command to turn the spindle ON eg M3 S1000
switch.spindle.output_off_command M5 # Command to turn the spindle OFF
switch.spindle.input_pin_behavior toggle # This pin toggles between it's on and off states each time it is pressed and released
For the enable ( TTL ) pin on a CO2 laser PSU, for power control use the Laser module.
# Switch module for laser TTL control
switch.laser.enable true # Enable this module
switch.laser.input_on_command M106 # Turn ON when M106 is sent
switch.laser.input_off_command M107 # Turn OFF when M107 is sent
switch.laser.output_pin 1.31 # Pin to control, to be connected to the laser power supply's TTL input
Note this is now supported by the laser module itself, where the pin is automatically toggled, using the laser_module_ttl_pin configuration option.
However, if you are not using that functionality, this allows you to turn the laser power supply using G-codes.
Smoothie has a reset button, and you can wire an external button to that ( see Pinout ).
However, maybe you have an existing Panel, which has a button on it, and you want to turn that into a reset button.
If that’s the case, you can setup a switch module to read whatever pin you wired that button to, and make it trigger the reset command whenever it is pressed, like this:
switch.reset.enable true # Enable this module
switch.reset.input_pin 1.30^ # Pin where reset button is connected
switch.reset.output_on_command reset # Command to reset the board
Let’s say your machine has a Y or Z axis that has not one, but two or more stepper motors.
If each of those has a separate stepper motor driver, and a separate endstop at the end, you can do something neat: multi-stage homing for auto-levelling/axis alignment.
The way this is accomplished is fairly simple:
Here is how you would set up switch modules for two stepper motor drivers:
# Switch module for first Z stepper motor driver
switch.z-1.enable true # Enable this module
switch.z-1.input_on_command M1001 # Turn ON
switch.z-1.input_off_command M1011 # Turn OFF
switch.z-1.output_pin 1.31 # Pin to control enable pin of driver
# Switch module for second Z stepper motor driver
switch.z-2.enable true # Enable this module
switch.z-2.input_on_command M1002 # Turn ON
switch.z-2.input_off_command M1012 # Turn OFF
switch.z-2.output_pin 1.30 # Pin to control enable pin of driver
For wiring, simply wire pin 1.31 to the enable pin of the first stepper driver and pin 1.30 to the enable pin of the second stepper driver.
| Wiring the same way you’d wire step and direction signals in the [external | drivers documentation](http://smoothieware.org/general-appendixes#external-drivers). ( note that if you will be using Open-Drain wiring, you need to add “o!” to your pin numbers, same as for step and dir ). |
You also need to wire the endstops so that a trigger is detected when either is triggered. This means if your endstops are wired as NC, you wire them in series, and if they are wiride as NO, you wire them in parralel.
And of course, both step and dir pins for the two stepper drivers must be wired in parralel to the same pins on the Smoothieboard.
Finally, when homing, you can’t simply issue G28, you have to issue a series of commands, which you can put at the beginning of your gcode files, or in your on_boot.gcode file ( which will be executed at boot time ).
Here is an example:
M1001 ; Activate both stepper drivers
M1002 ; Same
G1 Z10 ; Go up to make sure no endstop is hit
G28 Z0 ; Home the Z axis ( two motors together ) until one of the two endstops is hit
M1012 ; Desactivate the second stepper driver so we can home only the first one
G28 Z0 ; Home the first stepper motor/driver alone. First Z is now level
M1002 ; Re-activate second stepper driver so we can home only the second one
M1011 ; Desactivate the first stepper driver
G28 Z0 ; Home the second stepper motor driver. Second Z is now level.
M1001 ; Re-activate the first stepper driver, both stepper drivers are now active
; Z is now level relative to it's two endstops, and can be used normally as if it were a single axis.
Note if both your endstops are wired in parralel, you’ll need to retract off one endstop before you can use the next one. As long as you retract by the same length for each endstop you’ll be fine.
Note that with the first wiring, we rely on the enable pin to make sure that the drivers ignore step-dir instructions when we want to home the other axis.
However on some drivers, this will also turn off power to the motors