A wireless initiation device, comprising: a power source, a processing module for processing wireless electromagnetic communications signals received by an electromagnetic receiver system comprised in the wireless initiation device and associated with the processing module, the wireless electromagnetic communications signals including a wireless electromagnetic communications signal representative of a FIRE command, the processing module being configured to generate an initiation signal upon receipt of the FIRE command; a first housing within which at least one of the power source and the processing module is disposed, the first housing having a first connector; and an initiation unit having a second housing, within which is disposed an initiation module that is configured to discharge initiation energy sufficient to initiate an explosive charge associated with the wireless initiation device, the initiation module being connected to, or connectable with, the processing module such that the initiation module can receive an initiation signal from the processing module, and a second connector that is configured to mate with the first connector, thereby connecting the first and second housings, wherein the initiation unit is configured to energize part of the initiation module in preparation for discharge of the initiation energy upon receipt of the initiation signal, and wherein the initiation module is configured to execute a sequence independently of the processing module and the power source upon receipt of the initiation signal, the sequence resulting in discharge of the initiation energy from the initiation unit. a power source, a processing module for processing wireless electromagnetic communications signals received by an electromagnetic receiver system comprised in the wireless initiation device and associated with the processing module, the wireless electromagnetic communications signals including a wireless electromagnetic communications signal representative of a FIRE command, the processing module being configured to generate an initiation signal upon receipt of the FIRE command; a first housing within which at least one of the power source and the processing module is disposed, the first housing having a first connector; and an initiation unit having a second housing, within which is disposed an initiation module that is configured to discharge initiation energy sufficient to initiate an explosive charge associated with the wireless initiation device, the initiation module being connected to, or connectable with, the processing module such that the initiation module can receive an initiation signal from the processing module, and a second connector that is configured to mate with the first connector, thereby connecting the first and second housings, wherein the initiation unit is configured to energize part of the initiation module in preparation for discharge of the initiation energy upon receipt of the initiation signal, and wherein the initiation module is configured to execute a sequence independently of the processing module and the power source upon receipt of the initiation signal, the sequence resulting in discharge of the initiation energy from the initiation unit.