| Part | Total Qty. | Description |
| R1 | 1 | 470 Ohm 1/4 W Resistor |
| R2, R4 | 1 | 10K 1/4 W Resistor |
| R3 | 1 | 6.8K 1/4 W Resistor |
| R5 | 1 | 1 Meg Linear Taper Pot |
| R6 | 1 | 51K 1/4 W Resistor |
| C1 | 1 | 470uF 35V Electrolytic Capacitor |
| C2 | 1 | 0.001uF Ceramic Disc Capacitor |
| C3 | 1 | 0.05 uF Ceramic Disc Capacitor |
| C4 | 1 | 20uF 35V Electrolytic Capacitor |
| C5 | 1 | 6.8uF 35V Electrolytic Capacitor |
| C6, C8 | 2 | 0.01uF Ceramic Disc Capacitor |
| C7 | 1 | 100uF 35V Electrolytic Capacitor |
| U1 | 1 | LM1830 Fluid Detection IC |
| U2 | 1 | 555 Timer |
| Q1 | 1 | 2N5305 NPN Power Transistor |
| D1, D2 | 2 | 1N4148 Signal Diode |
| D3 | 1 | 1N4002 Rectifier Diode |
| K1 | 1 | Relay With 12V Coil (See Notes) |
| S1 | 1 | SPST Switch |
| PROBES | 1 | Stainless Steel Probes (See Notes) |
| MISC | 1 | Case, Knob, Board, Wire, Sockets For U1 and U2 |
Notes
- The probes should be made of stainless steel and mounted in a non-conductive fixture. Stainless steel nails, bolts or welding rod will make ideal probes. Good non-conductive materials are Lexan, plexiglass or plastic. The probes are to be placed at the liquid level at which you wish the pump to turn on.
- K1 should be chosen according to the requirements of the pump. If you are running a 12V pump then common automotive relays will work fine. If you are running a mains powered pump then you will need to make sure the contacts are rated accordingly.
- S1 provides a manual pump switch.
- R5 adjusts the on-time of the pump once moisture has been detected. It is adjustable from approximately 5 seconds to approximately 2 minutes.
- The probes should be cleaned periodically to assure reliable operation.
