Smoke alarm having layered structure

A smoke alarm having a layered structure, comprising:

• a case;
• a smoke detecting unit disposed in the case, wherein the smoke detecting unit includes a smoke collecting box and a control module electrically connected to the smoke collecting box;
• and
• a layering plate disposed in the case, wherein the layering plate defines an upper layer space and a lower layer space in the case, the upper layer space is a smoke guiding space, and the smoke collecting box is accommodated in the upper layer space to facilitate smoke-containing air to flow to the smoke collecting box;
• wherein the lower layer space is a module mounting space, and the control module is accommodated in the lower layer space to enable mounting of a sub-module of the control module that is detachable;
• wherein a plurality of narrow and long slots are formed at a periphery of the case and are spaced apart from each other to surround the case;
• wherein a length direction of each of the plurality of narrow and long slots corresponds to a direction from the lower layer space to the upper layer space;
• wherein each of the plurality of narrow and long slots is configured to be formed in spatial communication with both the lower layer space and the upper layer space.