Missing Schematics

[tommytamsen]

I've just acquired one of these monitors for my PC, C64 and Amiga and I just love it.
I really like your solution for the annoying Amiga input issue and would like to build a circuit myself.
But not having very much electronic skills I could use some help with the schematics, as not to destroy my dream Retro monitor.
I have references your information from:
https://github.com/stragulus/DellFP2001AmigaArduino
https://www.youtube.com/watch?v=gw1YQZlBUE4
https://forum.arduino.cc/t/how-to-detect-button-presses-on-a-device-and-how-to-press-them/352271
As I understand it I should build something like this:
`Input:
Button Arduino
Board Board
5 --> A0 Menu/Input
6 --> A1 Plus/Minus
12 --> GND

Output:
Arduino Monitor
Board controller
9 --> Low pass filter --> Original Pin 5 to monitor controller Menu/Input
10 --> Low pass filter --> Original Pin 6 to monitor controller Plus/Minus
`
In the Arduino forum you experiment with:

Using the online calculator below I created a low-pass filter with R=2kOhm and C=6.8uF (fPWM=495Hz). I replaced the cap with a 22uF one but the (LCD) monitor still wouldn't respond to any button presses.

I have no oscilloscope or advanced electronic skills, and hoping you could provide the low-pass filter components/schematics!
Are the filter build like this?