Since it's not very easy to find information online on how to build that type of lightgun, I decided to share the design I came up with, in case it might be useful to anybody else.
The base guns are a Namco Guncon and a Sega Virtua Gun.
Inside of each I first put an Arduino and a DFRobot IR Cam based on SAMCO's design, and then I also included a recoil solenoid along with the DIY control circuit, and Magic Trashman's awesome 3D printed clicky triggers with arcade switches (you can find him on tweeter).
Later I also added a rumble motor in the Virtua Gun handle (used when reloading, shooting offscreen, or changing lightgun mode ), and a foot pedal to the Virtua Gun that I can plug/unplug at will.
Here are some pics (I didn't install the rumble motor nor the foot pedal yet):
I known, the UP of the IR Cam is on the side, that's because DF Robot messed up their last series of IR Cam sensor and all the sensors are tilted on the side
Also, the cables aren't very clean and there is a lot of hot glue
I figured out the next best thing after 3D print to keep the extra button and the solenoid in place was hotglue. It's especially efficient with the solenoid since the flexibility of hotglue prevent it to move to much or damage anything.
Next time I will upload all the solenoid circuit Schematics and components ref when I finish them, since it was the hardest part to design.