Gordon Dabbled in Backyard Water Sports

By: 
September 13, 2004

Not satisfied with the flow rate he was able to achieve with his Super Soaker, Gordon decided to upgrade to a backyard dunk tank. By hooking up an off-the-shelf sump pump to a power supply and building in microprocessor control, he can blast a victim with up to 5 gallons of water when the target is hit. Switch inputs control the "douse" time from one to nine seconds. The microprocessor clocks data into a shift register to control the seven-segment time display. For easy disassembly and transport (it's great for office parties!), the frame is constructed of 1.5-inch PVC tubing screwed together.

"Sump" tank parts list
Amt Part Description Allied Part #
1 Circuit Board 0.1 grid 4 X 5 inch 237-0119`
1 Plastic Box (Serpac 131) 882-1131
1 10 K V Resistor, 1/4W, 5% 296-5586
1 1 K V Resistor, 1/4W, 5% 296-5562
7 470 V Resistor, 1/4W, 5% 296-5548
1 Shift Register (74HCT164N) 236-1759
1 7-Segment Display 782-0425
1 Octal Buffer (74HCT244N) 236-1775
3 Terminal Block 1 X 2 409-0111
1 Transistor 2N2222 248-1004
1 LM578M05CT Regulator, 5V Pos 288-0004
1 1N5400 Rectifier Diode 266-0008
1 Capacitor, 220 F, 25Vdc 852-7030
1 1N914 Diode 431-0618
1 Relay (10A, SPST, 5V) 788-1079
1 Power Supply 12Vdc 879-0215
1 General Purpose Snap Action Switch 821-1569
1 Pushbutton Switch for Changing Time 948-7193
Additional parts required: 8-pin Microprocessor PIC12F229, sump pump, PVC tubing, assembly hardware



For PDF links to Gordon Wall's instructions and drawings:

Dunk tank information


Sump pump directions


Dunk tank B.O.M.


Schematic drawing of sump tank


Schematic drawing of modified outlet

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