Do it manually first so by using a *Button Panel block and adding all the important to create a basic manual airlock.

1 - The hangar doors group set to open/close added to button #1.

2 - One air vent inside the hangar used to Press/Depress that must be connected to O2 tank (Balance tank) and not connected to O2/H2 Gen, to button #2.

3 - A second air vent (inside the hangar) turned OFF that must be connected to O2/H2 Gen. that you turn ON only to refill the balance tank when missing air in (emergency Air IN) to button #3 or #4.

*Button :
Aim at the button, hit K to open the block menu to drag and drop the hangar doors group and air vents to buttons :
Button #1 action = Open/Close hangar doors.
Button #2 action = Depress ON/OFF Air vent to Balance tank.
Button #3 action = ON/OFF air vent emergency Air IN.

Once the basic part is done, do the following Small ship setup for example.


1 - Add a *Sensor on the exterior of the station in front of the hangar door/access 1 where you want the ship to enter so to detect small ships getting close to the hangar doors.

2 - In the first sensor slot you will add the Air Vent Press/Depress (to balance tank) set to depressurize the hangar when small ship is detected so entering the sensor range.

3 - To the Air Vent Press/Depress right action slot you will add the Hangar Doors group (the access 1), that slot is triggered when the Air Vent detects 0% oxygen so set the hangar doors to open when at 0% O2.

4 - To the second sensor slot so the right one (on exterior sensor) you will add a *Timer block set to Start, Timer containing the Hangar doors set to close and the Air vent Press/Depress set to pressurize on exiting the sensor range.

*Sensor :
You will have to setup the needed range on the sensor so to detect small ship entering and exiting the sensor range, testing needed to find the proper values.

*Timer :
Add the Hangar doors group and Air vent Press/Depress to timer action slot 1 and 2 from the timer block in control panel and lower the time to minimum so it can start right away when activated.

Actions :
Sensor left slot action = Depressurize the hangar.
Sensor right slot action = Timer start Close/Pressurize, close hangar doors and pressurize.
Air vent Press/Depress right slot action = Open hangar doors.

The above are the basics, you may enhance to more advanced airlock using more Timers or air vent to add more actions like LCDs that will tell you what is going on, like this :

Take advantage of the Air vent Action Boxes :
- In the Control Panel, select a vent, then click the "Setup Actions" button.
- The Air Vent left box is triggered when the Air Vent detects 100% oxygen, the right box is triggered when the Air Vent detects 0% oxygen.