In video surveillance there is an ever-growing demand for heavily distributed radio cooperating objects that Wireless Sensor Networks (WSNs) can satisfy. We present a preliminary study of an energy efficient multimodal WVSN using a main node deciding which camera to trigger based on the information from a Pyroelectric InfraRed (PIR) network. The evaluation of the proposed approach against the solution with PIRs onboard shows significantly reduced cameras' ON-time, enabling network lifetime prolongation up to 75%. Furthermore, including cameras ' available energy in wake-up rules, which would be significant for the networks comprising a photovoltaic power source, augments additionally the system's lifetime. The performance of our approach is evaluated in MATLAB simulation.