Carbon monoxide detector reaction

I have recently bought a carbon monoxide spot detector which is not working the way I intended for it. A carbon monoxide spot detector is an analog carbon-monoxide detecting patch that changes color when it comes in contact with carbon monoxide. The problem is that it changes back to it's original color whenever the carbon monoxide leaves the room. 


I'd wish for it to stay the same color it changed to after it came into contact with carbon monoxide. What should the reaction look like to fix this problem? I have copy/pasted a scholarly paper from Google to better explain what's happening inside of the patch:



> 
> **Principle of the $\ce{CO}$ – Detector:** The palladium (II) chloride inside is reduced into metallic palladium when exposed to $\ce{CO}$. While the $\ce{CO}$ – level in air is rising, higher amount of palladium is formed. A color change of the solution from pale yellowish orange to orange or grey is followed.
>  $$\ce{CO + PdCl2.2H2O → CO2 + Pd + 2HCl + H2}$$
>  Afterwards, when exposing to $\ce{CO}$ – free air, copper (II) chloride oxidizes palladium back into palladium (II) chloride. In addition, copper (II) chloride is reduced to copper (I) chloride. 
>  $$\ce{Pd + 2CuCl2.2H2O → PdCl2.2H2O + Cu2Cl2}$$ 
>  Then, the regeneration of copper (II) chloride occurs. 
>  $$\ce{Cu2Cl2 + 2HCl + H2O + 1/2 O2 → 2CuCl2.2H2O}$$
>  Thus, the solution resumes to its initial state. (the oxygen comes from the surrounding air)
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