Switch module

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 inputs or custom G/M-codes, and outputs to GPIO pins or outputs custom G/M-codes.

This allows you to do one of the following :

  • Make a G-code control a GPIO pin
  • Make a GPIO pin cause a G-code to be executed
  • Make a GPIO pin control another GPIO pin
  • Make a G-code cause another G-code to be executed

You can create several different switch modules to fit your needs, within the same configuration file.

Like TemperatureControl, there can be multiple Switch modules. All you need to do is give each module it's 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 ...

All options

Option Example value Explanation
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.
switch.module_name.startup_state false Statup 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 Statup value of the switch if the output_type is pwm.
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 PWM, 20ms is 50Hz which is the default if not set
switch.module_name.fail_safe_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 fail safe value when a HALT condition is triggered
2017/01/25 14:20 · arthur

Startup State

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

Input Pin

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

Output Pin

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

Output type

There are three different output types : digital, pwm and hwpwm, the default is none so no output pin is configured.

Note that pwm is actually SigmaDelta Modulation and will allow you to set PWM intensity via the Shift 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 and ESCs. The Shift 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.

Commands and Gcodes

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.

Going further

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.

Fan

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

Hobby Servo

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
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             # Must be a PWM capable pin
switch.servo.output_type                       hwpwm            # H/W pwm output settable with S parameter in the input_on_comand
#switch.servo.pwm_period_ms                    20               # set period to 20ms (50Hz) default is 50Hz
# Switch module for a second servo control
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_comand

To find a PWM-capable pins, see Pinout

Power supply control

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.fail_safe_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
2017/01/25 14:19 · arthur

Pause when out of filament

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.

Suspend and resume buttons

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

Stopping Smoothie

These are the different ways of stopping Smoothie :
Command G-code Movement Heaters File playing Recoverable Documentation Explanation
abort M26 Stops 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.
suspend M600 Stops once queue is empty Turned off if option enabled (default) Paused, can be resumed Yes, with resume or M601, position maintained Player 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. M601 resumes the print or the resume command
No command, but there is a configurable «kill» button M112 Stops 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 M999 is 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 M999 is sent (or $X). Position is lost.

If the kill button is pressed (or there is a temperature fault, M112 is 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 issuing M999 or 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.

2017/01/25 14:20 · arthur

Suspend/resume single 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

Spindle control button

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 S1000                 # Command to turn the spindle ON
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

Laser power supply

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.

Setting up a reset button

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

Console command to read a switch state

Smoothie console can be used to read and output the state of an input switch.

config definition

## VACUUM SENSOR HEAD 1
switch.vac1read.enable                           true            #
switch.vac1read.input_pin                       3.26             #
switch.vac1read.input_type                      digital          # just an on or off pin

console command

The @ is an escape character for Pronterface to not filter the non g-code.

@switch vac1read

The console output will be

switch vac1read is 0