An explosives detonator system includes a detonator housing within which is provided a detonation circuit that includes a conductive pathway having a fuse head integrated therewith such that the conductive pathway passes along both electrodes and a resistive bridge of the fuse head. An uncharged chargeable voltage source is also integrated with the detonation circuit and is electrically sensitive to a charging property which is included in a charging signal. Exposure to the charging property charges the voltage source, thereby rendering it capable of generating a potential difference between the electrodes at least to equal the breakdown voltage of the resistive bridge. The charging property is any one or more of a charging light pulse, a charging temperature, a charging pressure and a charging radio frequency.