determining, by at least one processor, whether a measured characteristic variable of the respective space satisfies one or more conditions for generating a maintenance request;

in response to detecting a bin-liner switch switched from a bin-liner-in position to a bin-liner-out position, determining that a bin-liner is being removed from the respective space, wherein the bin-liner switch comprises a lever configured to switch to the bin-liner-in position when the bin contains the bin-liner in the respective space and switch to the bin-liner-out position when the bin does not contain the bin-liner in the respective space based on tilt movement of the lever;

in response to determining that a condition, from among the one or more conditions for generating the maintenance request, is satisfied by the measured characteristic variable of the respective space, generating, by the at least one processor, the maintenance request in association with an identifier of a corresponding sensor system among the one or more sensor systems, wherein the corresponding sensor system includes the bin-liner switch;

selecting a mobile device, from among multiple mobile devices registered to multiple users, based on the selected mobile device being associated with a user currently in a building associated with the one or more sensor systems; and

transmitting, by the network interface, a message to the selected mobile device, the message including the maintenance request that notifies the user of the mobile device to perform a task to change the characteristic variable of the respective space,