http://blog.makezine.com/2008/08/13/laser-modem-with-an-ardui/

Does it have to be Arduino alone ?

Could you use Arduino to read the flex sensors and offload the gesture recognition to a PC ?
That would be much better.

the most important thing is to choose an Arduino board that matches the WIFI board you choose.

I think logging to an SD card will be much easier.

WIFI is going to be difficult for such a large area, and it will use more power.

How are you going to monitor temperature? on the surface of the sheep? Direct unlight could be a problem.

How small is "a small area"?
How large is the animal ?

How many hours will you need to track the animal?

Battery power will be a potential problem, especially if you go the wifi way.

Is it possible that you are using up all the available RAM ?

74hc595 for instance.

They are rather cheap.

Depending on what you are goint to control you might need other tuff as well. Like the Arduino pins you can't draw much current from the shift register pins.
Shift registers with high current draw capability are available but they are much more expencieve. You should alo conider your power upply needs.

If you tell a little about what you are going to control we could probably give better advice :-)

The Loop() will alway run.

So you must structure your program in such a way that there will be a state where the loop is "idling".

That does not mean that everything must be in the loop, you can have functions outside the loop that you call from within the loop.

Or you could use softserial:

PC1 -> ordinary serial (USB) -> Arduino1 -> soft serial -> Arduino2 -> ordinary serial (USB) -> PC2

Check out the "blink without delay" sample code in the playground.

Why not just hack into one of these:

http://www.aliexpress.com/item/free-shipping-USB-TO-Keyboard-PC-MIDI-Interface-Adapter-Cable-9773/286559549.html.

You just need to have your Arduino send MIDI out on the serial , the interface would be recogniced as a MIDI devive on the PC.

Sending MIDI over serial with Arduino is well documented, and simple.

Your loop() is alway running.

So if you call your function from within loop, program flow will always be returned to loop when you exit your function.

So you need to implement the logic to read the switch in your function and then exit the function when the switch is pressed.

Do you have access to a volt meter, or even better an oscilloscope ?

It would be a good idea to measure what ever is on that jack before doing anything with it.

Measureing or "scoping" the ignal could also give you an idea about what the signal is (probably a series of pulses).

Using Goto is considered very poor programming practice. It makes it very difficult to read a program and to understand the structure of the program


You just call your function like this:

Delay_function();

When it is finished doing what it should, program flow will be returnd to where you called it from.

Do you really mean servos, they usually only rotate 180 degrees ?
Do you need full rotation or just, less than 180 degrees back and forth movement?

H bridges are usually used for DC motors not for servos. If what you really need is DC motors you will need geared motors to get 1 RPS, an you will need one H bridge for each motor if you need individual control over speed and direction. Geared motors that go down to 1RPS = $$$

Do you need individual speed/direction control over the 24 motors?

Wireless control over what distance ?

When you say "waterproof it", will it be submerged?, because that will have an influence on wireless options.

Have you considered your powersupply needs?, if what you really need is DC motors, you are going to need a beefy powersupply to run 24 of them.