sendkeys - send input events based on pins or scancodes from HAL


loadusr sendkeys config=s8t5, 16, t12


This component is intended as a partner component to matrix_kb or the hostmot2 7i73 driver. It accepts the key-up and key-down event codes from either of these and converts them to keystrokes sent from a virtual keyboard.

It also allows for keystrokes to be generated by individual HAL pins.

The config parameter to the loadusr HAL command defines how many scancodes will be supported and how many individual pins are created. config=s16 would support the 16 scancodes of a 4x4 matrix. config=t10 would create 10 individual HAL pin triggers. config=s16t10 would create one instance with both the above.

Multiple configs separated by commas will create multiple instances of the component. The accepted codes can be seen in the extract from the linux headers here:

The component requires the user to have write permissions to /dev/uinput which is not available by default. To give access:

Create the uinput group and add the LinuxCNC user to it:

sudo groupadd -f uinput
sudo gpasswd -a username uinput

Create a new entry in .B/etc/udev/rules.d/99-input.rules

sudo echo KERNEL=="uinput", GROUP="uinput", MODE:="0660" | sudo tee /etc/udev/rules.d/88-input.rules

Then reboot the machine. You can test that is has worked:

ls -l /dev/uinput
crw-rw---- 1 root uinput 10, 223 Nov 11 15:35 /dev/uinput

It is possible to link the 7i73 codes to both the matrix_kb comp and this comp, so that some codes operate HAL pins and some send keystrokes. Where the option exists it is MUCH better to use HAL pins for things like jogging and machine control. This component should really be used only for text entry and GUI operations.

Each key on the matrix is allocated a scan code. The simplest way to configure the component is to load the component and open a halmeter showing sendkeys.0.current-event. Note the code for each physical key. (If keys do not give consistent results then you probably need to toggle the value of the matrix_kb.0.negative-logic pin and/or invert io pins).

Then edit the HAL file to assign a key event to each scancode. For example:

setp sendkeys.0.scan-event-21 34

To set a button to type the letter "G" The key events related to each physical key need to be set up prior to the component activating, but after the component is loaded.

To achieve this there is a pin sendkeys./N/.init which should be set to "true" once the events to be sent for each scancode and pin have been set up.

To generate keystrokes from other sources note that a keydown is simply 0xC0 & keycode and keyup is 0x80 & keycode.


sendkeys.N.keycode u32 in Connect to scancode generator.

sendkeys.N.current-event s32 out shows the current scancode without keyup / keydown markers.

sendkeys.N.init bit in set this pin TRUE once all the event parameters have been set.


sendkeys.N.scan-event-MM u32 in assign the uinput event codes associated with each scancode. u32 in assign the uinput codes associated with each HAL bit pin.


loadusr -W sendkeys config=16t2
net scancodes hm2_7i73.0.0.keycode => sendkeys.0.keycode

setp sendkeys.0.scan-event-00 34 # Key G
setp sendkeys.0.scan-event-01 2 # Key 1
setp sendkeys.0.scan-event-02 3 # Key 2
setp sendkeys.0.scan-event-03 4 # Key 3
setp sendkeys.0.scan-event-04 50 # Key M
setp sendkeys.0.scan-event-05 05 # Key 4
setp sendkeys.0.scan-event-06 06 # Key 5
setp sendkeys.0.scan-event-07 07 # Key 6
setp sendkeys.0.scan-event-08 31 # Key S
setp sendkeys.0.scan-event-09 8 # Key 7
setp sendkeys.0.scan-event-10 9 # Key 8
setp sendkeys.0.scan-event-11 10 # Key 9
setp sendkeys.0.scan-event-12 20 # Key T
setp sendkeys.0.scan-event-13 11 # Key 0
setp sendkeys.0.scan-event-14 52 # Key Dot
setp sendkeys.0.scan-event-15 14 # Backspace
setp 29 # Left Ctrl
setp 57 # Space
setp sendkeys.0.init 1

#Send Ctl + Space from one trigger
net clear-errors sendkeys.0.trigger-00 sendkeys.0.trigger-01


Andy Pugh