foone , Englisch 
watching the latest Deviant Ollam talk, they mentioned wondering if you can just trigger carbon monoxide sensors with some chemistry.
Turns out you can just buy tester canisters! They're just spray cans of Carbon Monoxide! That sounds... somewhat dangerous.
https://www.amazon.com/Sdi-Carbon-Monoxide-Detector-Tester/dp/B007886ZME