It also supports Digital LEDs such as WS2812 or PL9823. This way you can have as many LEDs as you want and you can also define the color of them with just one Pin.
In LinuxCNC each LED is listed as one Output that can be set to HIGH and LOW. For both States you can define a color per LED.
This way, you can make them turn on or shut off or have them Change color, from Green to Red for example.
To Install LinuxCNC_ArduinoConnector.ino on your Arduino first work through the settings in the beginning of the file.
The Settings are commented in the file.
To test you Arduino you can connect to it after flashing with the Arduino IDE. Set your Baudrate to 115200.
In the Beginning the ARduino will Spam ```E0:0``` to the console. This is used to establish connection.
Just return ```E0:0``` to it. You can now communicate with the Arduino. Further info is in the Chapter [Serial Communication](#serial-communication-over-usb)
Digital Inputs use internal Pullup Resistors. So to trigger them you just short the Pin to Ground. There are two Digital Input Types implemented.
Don't use them for Timing or Safety relevant Stuff like Endstops or Emergency Switches.
1. INPUTS uses the spezified Pins as Inputs. The Value is parsed to LinuxCNC dirketly. There is also a inverted Parameter per Pin.
2. Trigger INPUTS (SINPUTS) are handled like INPUTS, but simulate Latching Buttons. So when you press once, the Pin goes HIGH and stays HIGH, until you press the Button again.
Digital Outputs drive the spezified Arduinos IO's as Output Pins. You can use it however you want, but don't use it for Timing or Safety relevant Stuff like Stepper Motors.
# support of Digital RGB LEDs like WS2812 or PL9823
Digital LED's do skale very easily, you only need one Pin to drive an infinite amount of them.
To make implementation in LinuxCNC easy you can set predefined LED RGB colors.
You can set a color for "on" and "off" State for each LED.
LED colors are set with values 0-255 for Red, Green and Blue. 0 beeing off and 255 beeing full on.
Here are two examples:
1. This LED should be glowing Red when "on" and just turn off when "off".
This is a special Feature for rotary Selector Switches. Instead of loosing one Pin per Selection you can turn your Switch in a Potentiometer by soldering 10K resistors between the Pins and connecting the Selector Pin to an Analog Input.
The Software will divide the Measured Value and create Hal Pins from it. This way you can have Selector Switches with many positions while only needing one Pin for it.
You can adapt the Settings to fit all kinds of Matrix Keyboards. The Software can emulate an Keyboard in Linux. This is useful, because for some Keys you may want to enter Letters or Numbers, for others you may want to set functions in LinuxCNC. To input Text it is neccessary to emulate Keypresses.
In the Config file you can define, which Key should be connected to LinuxCNC as Inputpins and which should be handled like a Keyboard in Linux.
To run Matrix Keyboards requires you to install and test "xdotool".
You can install it by typing "sudo apt install xdotool" in your console. After installing "xdotool type "Hello World" should return "Hello World" in the Terminal.
If it doesn't, something is not working and this program will not work either. Please get xdotool working first.
In the Settings a cheap 4x4 Keyboard is used such as https://theartoftinkering.com/recommends/matrix-keyboard/ (referral link)
After Bootup the Arduino will continuously print E0:0 to Serial. Once the Host Python skript runs and connects, it will answer and hence the Arduino knows, the connection is established.
For testing you can still connect to it with your Serial terminal. Send ```E0:0```, afterwards it will listen to your commands and post Input Changes.
Data is always only send once, everytime it changes.
| Latching Potentiometers | L | write only |0-max Position|
| Absolute Encoder input | K | write only |0-32 |
| Connection established | E | read/ write |0:0 |
Command 'E0:0' is used for connectivity checks and is send every 5 seconds as keep alive signal. If it is not received in Time, the connection is lost and the arduino begins flashing an LED to alarm the User. It will however work the same and try to send it's Data to the Host.
