water sampler - part II

[timothyp]

Thanks for all the input on the FFCF (fish fecal collection filter). Many good ideas have been offered and from all these ideas I'll work on constructing something simple, reliable, and relatively inexpensive.
I'm steering towards C. Foley's concept of the 4rpm gear motor, with mini gear pump (@ 2 Lpm flowrate), rotating plate, and pic control. I have only "played" w/ the Basic stamp kits and plan to utilize the BS2 BoE kit for control operations. It'll be a bit more challenging then programming blinking lights and push button switches!
The reason for the 20 min intervals is to minimize leaching of fecal nutrient material (N, P, C) into the water. So, if we remove it from the water, pump it on to a 50-60 micron stainless screen filter, most all of the solids material can be captured. The filter in mind is approx. the size and ht. of a lid for a 5-gal bckt. After 12h, filter is removed, placed into the oven, fecal solids dried, and weighed. Data is used to evaluate diet utilization and feed energetics.
I'm looking to construct a prototype. If it works well enough we will utilize on several exp. culture tanks. Preliminary budget for prototype is ~$500 +/- $100. Alternative, rent a sequential sampler for a month or two. Although, the mechanical rotational timer ideas have my interest due to potential simplicity.
A couple of definites. Water must fall back into the tank. Sample interval is 20 mins. Minimize sample discharge overlap onto filter screen (don't want to wash previous sample back into tank). 12h sampling period btwn filter changes. Sample volume 1-2 liters w/ emphasis of obtaining the settled fecal material on the tank bottom. (It may take 1 min, 2 min, 3mins, ... to clear tank bottom of fecal material. Obsevation will indicate pump duration time).
Thank you all again for the positive inputs and ideas. ... Tim P.

[grant fair]

A stepper motor controlled through the parallel port of a ms-dos computer is easy to implement. An adaptable and inexpensive project by James Barbarello “Build this automatic parts tray”, Electonics Now, November 1996, would be easily adaptable to your project, I suspect. Programming in QuickBasic would be quick and easy.<p>Steppers are availabel from Jameco, Herbach and Rademan, C & S, Halted, etc; they are all on the net.<p>Grant

[Dimbulb]

I like the way you are adding more detail on your circuit.
The timer I was thinking of is not cheap but it should have enough torque and mounted ready to run.
cut three 1/8 inch thick by 1 by 3 rectangular aluminum tubing 3/8 inch long drill both ends on center and pop rivet to the circular timer face. Attach plastic lid slightly off center.<p>http://www.intermatic.com/comind/t100.htm<p>Can you list more on what parts you need ?
On the pic controller what exactly does it do ?
What will you use for a power supply ?
What size stepper motor ?
How does it connect ?<p>[ April 12, 2003: Message edited by: 1206DX ]</p>