Nice setup! You've made a great application for the target circuit.

Yup, the detector is sensitive to all infrared. Sometimes just flourescent light will set it off. I do have a board that will discriminate between other signals and only respond to the Tamiya signal. It works with the battle circuit (connects between detector & board). The targets are pretty much stand alone and would not work with this. But your solution is perfect, shield it from other sources with only one point of access.

I'm working on one that will count the number of hits (selectable from 1 to 9) then activate a relay, it will also have two additional relays, one for sound and one for another device, maybe a smoke unit like you have? With the extra relays and other devices it would need a larger power source, the 9 volt battery would not be sufficient. I guess it should detect the Tamiya signal to be more selective also?

So you verified the VStank infrared works with these circuits? That's good to know, thanks.