Electronic Circuits and Projects Forum

First of all, well done in explaining exactly what it is you are trying to do, clearly explaining the problem and obviously making a start on the work yourself.
UNLIKE many of the idle third world students (and some first world) who come here expecting the complete work done for them. Oh and they need it by next week!
[rant_mode: OFF

Originally Posted by steve_j83

Looking at the schematic here where i am struggling

1. The input output polarizer. How does this work? I dont really understand how it would be wired. Its confusing me quite a bit, why have the tracks comming from the electrodes (bp 1 and bp2) been crosed over each other?

Quite simple, it is just a double pole double throw switch with a simple wiring scheme (very simple when you see it done) to swap the polarity of the input signal from the plant to make the meter move in the correct direction.

Originally Posted by steve_j83

2. How viable is this in terms of part avalibility? I think the ic might be a little out of date but shouldnt be to hard to find a sutible replacement. Any advice as a whole?

The IC in the circuit, the 741 is still readily available, however, before the pack descends and tells you it is old and inferior, I will just say that something like a TL071 would be a better choice.

Originally Posted by steve_j83

3. I need the output to be in a voltage range of bewteen 0-5volts. A range of 0-1 would suffice though. Where would be the best place on the schematic for me to take the output to be sent into the arduino? At the dc recoreder or the audio output? Im asuming the dc recorder but im not sure what voltage range it will be outputing.

First of all, what is an arduino? (On edit, OK I just googled it!)
The output voltage will depend on the input from the plant, so, dificult to predict.
I think that you need a DC voltage, so the recorder output is probably what you need to use.

JimB

Try this as a modified circuit.

On further thought, you could probably leave out the meter.
Also the 0.01uF capacitor.

JimB

I am really a bit sceptical to this whole idea. Plant physiology really does not seem to lead one to believe that plants could respond to sound. They just don't have a mechanism for doing so. Most of a plant biological makeup is chemical reaction. The plant stoma open and they draw in CO2, at same time the stoma draw water from the root through the xylem tissue. All Chemistry based. Plants have no CNS, so I think the whole idea of plants reacting to sound is somewhat silly.

Measuring resistance change would be nothing more than coincidental. Ie. plant is uptaking water with nutrient in it. Certain nutrients would affect the electrolyte levels of the plant thus creating an illusiion that the plant was undergoing some sort of change. Just silly I think.

I had a look at the switch, i think i understand it. Is this correct?

(hardly pro but I only had paint on hand)

Hmm now im thinking i might be wrong.. another go.