Currently selling Pyronix KX15DQ PIR's at £10 each (plus P&P) on ebay :-
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a.. 15m Range b.. Selectable End of Line (EOL) resistors c.. Aspherical lens d.. Selectable Normally Open (NO) or Normally Closed (NC) relay e.. 15m Detection range f.. Digital Temperature Compensation (DTC) g.. Signal Processing
h.. Intelligent noise reducing Independent Floating Thresholds technology (IFT)
i.. Supplied with wall and ceiling brackets