make a tank one next i am building a tank rn

In Stormworks the "constant on blocks" are meant to send out an 'on' value to anything they are connected to(as the name suggests). These blocks have three different damage states they can achieve:
1st - no damage = block sends a constant "on" output to my MC;
2nd - slight damage = block sends out a pulsating "on" signal;
3rd - heavy damage, destroyed = block doesn't send out any output (aka. the "on" output switches to "off").
My MC takes these constant on outputs from different blocks around your creation and projects them onto a screen. If all constant blocks from one limb are in the 1st state (no damage) then the limb appears green on the display. If your limb gets shot by something (anything that will damage the constant on block placed in the limb) then it will show up as a pulsating icon on display. If that constant on block will be in the 3rd state(completely destroyed) then the display will let you know that it's badly hit.

How would i detect the damage?