RubberJogi

What is the idea / the usecase ?

You want to control a PC from another PC, making keystrokes, eventually mouse-moves.
Even when starting up and e.g. entering the BIOS
=> ssh etc not an option
you need to be independent from any "client" on the controlled machine
only solution which comes to mind is : USB HID
Therefore you connect from PC I somehow to PC II, on PC II as USB-Keyboard

Solution : RubberJogi

+----------------+                                  +----------------+
|                |                                  |                |
|    PC I        |                                  |    PC II       |
|                |          +-------------+         |                |
|  (Controller)  | USB      |             |  USB    |  (Worker)      |
|                +--------->+ RubberJogi  +-------->+                |
|                | serial   |             |  HID    |                |
|                |          +-------------+         |                |
|                |                                  |                |
+----------------+                                  +----------------+

PC I connects to RubberJogi via USB-Serial
RubberJogi injects Keystrokes etc via USB HID to PC II

Ingredients Hardware

Arduino ( with USB-Keyboard capability), e.g. Leonardo, Micro, etc
USB-TTL UART Converter , FTDI Serial
some cables

Ingredients Software

As it is not possible to send CMD-Keys like ALT, CTRL via serial line, a language has to be used.
Avoid to reinvent the wheel ==> Compatible to the famous RubberDucky-Script-Language
==> Based on arducky by Baptiste MOINE (Creased), THANKS!
Parser is based on https://github.com/Creased/arducky/blob/master/arducky.ino
is partially extended for also sending MOUSE-Movements
is already extended to control four additional GPIO-Switches
Accepted Commands :
- All RubberDucky-Commands (not really all...)
- backspace
- switch1_on / switch1_off => switching Optocoupler at Pin2
- switch2_on / switch2_off => switching Optocoupler at Pin4
- switch3_on / switch3_off => switching Optocoupler at Pin6
- switch4_on / switch4_off => switching Optocoupler at Pin8
- boot => switching Optocoupler at Pin2 for 1.5 sec high, then low
- reboot => switching Optocoupler at Pin2 for 10sec high, then low, after a delay of 2 secs then once more for 1.5 sec high, then low
- aten => switching Optocoupler at Pin4 for 1.5 sec high, then low

Controlling

For "talking" to the RubberJogi from PC1 you need to configure your serial port to

9600 Baud
8 Bit, 1 Stop-Bit, No parity

If you are using a linux-box you could use the follwing command to achieve this:

stty -F /dev/ttyUSB0 cs8 9600 ignbrk -brkint -icrnl -imaxbel -opost -onlcr -isig -icanon -iexten -echo -echoe -echok -echoctl -echoke noflsh -ixon -crtscts
Then you can just try out the functionality of the box with e.g :

echo "ENTER" > /dev/ttyUSB0 when you are allowed to use /dev/ttyUSB, or
echo "ENTER" | sudo tee /dev/ttyUSB0 when you need to be root to use /dev/ttyUSB

In both cases you should see a moving text-cursor on the second PC (best open an Editor...)

Special Hardware with 2 switches

In our/my usecase we also need to control two switches
one of these is connected to the reset-button of the PC
the other one is connected to the switch of a USB-sharing station, so we can switch a USB-stick between PC1 and PC2 ...
more explanations will follow, the code is already able to make use of these
here at least are the schematics
In case you want (like we do) to switch on PC2 with a command from PC1 you need to connect Vcc between FTDI and Arduino, otherwise the Arduino will not have power when he is connected to a switched of PC ... ( see the green cable below)
Unfortunately, it looks like this is backfeeding 5V even to the 2nd PC via USB. This is not a problem if the PC is switched on. BUT : If you have the PC switched off and want to switch it on, then - depending on the PC - it might make some trouble for the PC, as it is never really switching completely off. I need to try this remedy : https://forum.arduino.cc/t/powering-the-arduino-with-a-5v-power-supply/261902/12
We tried out this remedy (remove T1 of the ARDUINO) and it works perfect. BUT beware: when you want to re-programm the Arduino you NEED to have the FTDI connected as well to a PC, as otherwise the Arduino is not powered...
See here the location of the T1 to be removed:

Extended Special Hardware with 4 switches

in the meantime we even have use-cases where we need to control up to 4 switches
as before one of these is connected to the reset-button of the PC (in our case)
as before one is connected to the switch of a USB-sharing station, so we can switch a USB-stick between PC1 and PC2 ... (in our case)
the other 2 switches are needed to control boot-sel switches of embedded ARM systems
here are the additional schematics
In case you want (like we do) to switch on PC2 with a command from PC1 you need to connect Vcc between FTDI and Arduino, otherwise the Arduino will not have power when he is connected to a switched of PC ... ( see the green cable below)
backfeeding 5V via USB to PC2: see above at the 2-Switch-Solution)

Extended Special Hardware with 5 switches and one relay

finally (in our application) we need to switch power
we introduced a 5th optocoupler, connected to pin10 AND we connected a real relay to that to be able to switch power
schematics will follow

Reality

This is one sample-prototype without any switches, just the "plain" RubberJogi. This was soldered "flying" and is only stabilized with heat shrink tube.

This is one sample-prototype, with 4 switches, soldered on a veroboard/breadboard

These are all 3 prototypes I have built, together on one picture.

2 times extended RubberJogis with 4 switches
1 as a pure RubberJogi, no switches.

Parts-List

What do you need to build a RubberJogi?

Part	Rubber Jogi Standard	Rubber Jogi Two Switch	Rubber Jogi Four Switch
Arduino Micro	1	1	1
FTDI USB / Serial Converter 5V capable	1	1	1
Cables between Arduino/FTDI (Vcc, GND, RxD, TxD)	4	4	4
USB-Cable to Arduino (USB-A to Micro-USB)	1	1	1
USB-Cable to FTDI (USB-A to Mini-USB)	1	1	1
Veroboard	?	ca 60x50 mm	ca 60x50mm
Header Arduino (when not using already w/ headers)	?	34	34
Header FTDI	?	18	18
Optocoupler 4N25 DIL	0	2	4
Resistor 390 Ohm	0	2	4
Connectors, depends on your needs, e.g	0	2	4
Example: Headers for switches	0	4	8

Links, Ideas

Mouse-Support currently missing to 90%, positioning does not work. Maybe move to USB-Touch-Screen could solve the problem? Please have a look at this project, might be worth checking out : https://github.com/NicoHood/HID
Another potential usefull link to solve the mouse-move would be : https://www.codeproject.com/Articles/1001891/A-USB-HID-Keyboard-Mouse-Touchscreen-emulator-with

jogi-k/RubberJogi