Light sensitive arrangement for a detonator

A detonator which in use is connected to an elongate light transmissive or light generating conductor, the detonator including a communication module and a light sensitive arrangement, wherein the light sensitive arrangement includes a detector, a light sensor, a first impedance, a second impedance, and a switch, which is connected in series with the second impedance, wherein the light sensor, in response to an incident first light signal produces an output current which is directed through the first impedance to produce a voltage which is output to the communication module, and wherein the detector is configured to detect a second light signal which is associated with initiation of the detonator and which, upon detection of the second light signal, causes the switch to be closed so that the output current of the light sensor is then directed at least through the second impedance to produce a second voltage signal, and wherein the first impedance is higher in value than the second impedance.