Why an electronic cricket? Many people like the cricket sound specially if they live in a big town. This electronic cricket circuit works in pulses, so the battery life is prolonged, the current consumption is just 2mA.
The electronic cricket schematic is very simple, it is build with CD4049 or CD4009 wich is CMOS Hex Buffers/Converter.

Electronic cricket circuit diagram

Electronic cricket
And here you have the electronic cricket simulator pcb:
electronic cricket pcb 220x300