R1 = 470K N1, N2 = MC14093B R2 = 15M* T1 = 2N3906 (these will work also: PN200, 2N4413) C1-C4 = 2N2 (2. 2nF) (NTE159, ECG159, BC557, BC157, TUP ) D1 = 1N4001 Ry = Relay (12V or matching supply voltage) D2, 3 = 1N4148 Sensor = Stainless Steel probes, brass,....