Nuts and Volts - May 2008

standards, and a length of metal coat hanger to blouse the dyed water hose.

I was fairly cavalier in attaching all of these bits to the plastic box, using #6 machine screws and zip ties. These served to mount the main circuit and the LED standards while the pump sported four suction cups on its base. I was able to keep it from sliding around after cleaning the bottom of the box with denatured alcohol.

The pump I bought came with a pile of extensions and adapters. I found that the one that converted the output to 1/4” OD plastic hose was the best. Not surprisingly some drip irrigation parts worked the best for the hose and the emitter (a 2 GPH dripper.) As you can see in Figure 1, I simply zip-tied it along to the coat hanger. Bending the coat hanger wire to attach it to the basin was a trick

The PCBs and/or a complete kit for this project can be purchased through the Nuts&Volts Webstore at www.nutsvolts.com or call our order line at 800-783-4624.

(Figure 6). The final height and orientation is unimportant as it can be compensated with by the pump speed control.

The UV LED standards were built quite easily using some more protoboard and Chem Wick desoldering braid. I placed the LEDs every 0.6” and soldered them in parallel on the back of the protoboard (Figure 7). A dab of hot melt glue on the back secured the leads enough to allow refocusing. The pump came with 15 feet of cable so I chopped it up to wire the standards and all of the components on the main controller board.

The final — and most messy — part of the project is creating the dyed water. It turns out that a yellow Sharpie Accent highlighter contains everything you need. Simply pop out the end cap, extract the dye-soaked core (Figure 8), and wring it out in the water of your catch basin. If you’re building this project with your kids, you will want to hand this off to them as it’s the most messy. In my prototype, I found that two highlighters contained plenty of dye to color a quart of water. And they only cost about 25 cents apiece. (When you’re done, drain the