That should be a good starting point. I would just eliminate the output mosfet transistor as it would otherwise require a load resistor to actually develop a output voltage when 'on', but possibly enabling the internal pull-up resistor for the digital input pin would work with the transistor shown.

Just wire the top side of the 4.7 megohm resistor directly into a Arduino input pin should work fine. You might also want to power it from the Arduino +5vdc voltage pin instead of the 3v battery. The standard Arduino has a 3.3vdc power pin available also. Don't forget to wire a ground from this circuit to an Arduino ground pin.

Good luck;

Lefty

Not a guru by any means, but your flow chart shows very logically what you want and the Arduino certainly has the means to execute the logic (enough memory, enough speed, etc). The Arduino would seem to have enough inputs and outputs to handle the tasks also. What is not clear is how much external circuitry will be required to interface the various inputs and outputs.

Switching audio sources between the various sound generators (radio, mic, ipod) to the one headset is pretty simple and can be done with either Arduino controlled relays or op-amps (I think headphone audio might be too high a level and current to use simple analog mux chips by themselves).

You will need some kind of analog op-amp circuits to be able to detect the presence of sound from the mic and radio  so that adds to the external circuitry needed. Mic level is especially low level so that would take some extra amplification, radio sound output is a little higher output so possible a simple diode rectifier/filter circuit would drive a analog or possibly even a digital input to the Arduino.

Lastly you need to be able to control the ipod. That I have no knowledge of, so the first question is does the ipod have external control inputs that would allow manipulating the ipod operations? If not it would be a most difficult problem. if it does you would probably just need external interface components like optical isolators to command the ipod.

 So the big challenge is not in the Arduino, the real challenge is all the external interfacing circuitry that you will have to develop. And that would be true no matter what brand or model of micro controller you try and use.

Lefty

I use brey terminal. While maybe not the simplest it is among the most powerful and useful windows serial terminal program. It's free and it's a pretty small standalone EXE program (no dll or other support required) that doesn't need to be installed, just launched. I carry it around on my usb memory stick also.

Lefty

By the way it's [glow]Relay[/glow] not  Realis  

Left

Code:

With this knowledge, could I not do something similar and power my solenoids off the 5V pin and connect all the grounds to pins on the Atmega? I've worked with 8051's in the past where instead of doing this I used a buffer chip as a current sink. Would this be a better solution?

Note unless the solenoids draw less then 40ma each, 30ma or less is better. In that case the current would flow from +5vdc to the solenoid and on to a digital output pin, so the pin current limit still applies. The output pin current limit is the same no matter if it's sourcing current (HIGH output) or sinking current (LOW output).

Lefty

Windoze does have its own serialkeys program (in accessibility options)

Is there a good reference source for this option to read about this before mucking with Windoze?

Lefty

What is wired to the input of the isolator? If it's a mechanical switch contact of some kind then contact bounce could always be a possiblity of flaky or inconsistance readings.

Lefty

Just a quick shot in the dark. Seeing the I2C address you are using, did you remember to ground the A0,A1&A2 inputs (pins 5,6,7)? If not grounded they would probably 'float' high and thus creating a different device address.

Lefty

So, it looks like my temperature sensor is sensing around room temperature, and because I don't have a voltmeter to check my arduino's actual voltage

But you can calculate the applied voltage indirectly but just taking the 'raw' value from a analogRead() statement which gives you a raw count from 0-1023. Take the raw count and multiply it by .0048 and you will get the 'raw' voltage being applied to the pin, give or take a few counts depending on how close to +5vdc the actual board voltage is.

Lefty

I don't think you have the sensor wired correctly. I haven't used that chip but it's datasheet application section clearly shows a load resistor required. In fact without such a resistor you may have damaged the sensor, but I can't state that for sure.

http://www.national.com/ds/LM/LM135.pdf

Lefty

H-drives are for single winding DC motors, not stepping motors. Stepping motors have  multiwinding and are usually controlled by proper sequencing of digital outputs with current drivers. A stepper motor controller is a different animal then a H-drive motor controller.

Lefty

http://arduino.cc/en/Hacking/PinMapping168

The main complaint I hear is about the shipping time for E-bay Asian sellers. My orders almost always arrive on the west coast here in 10 days. give or take a day. However as a retired old guy I have no problem with waiting for orders, I have patience and my smallest unit of time increment is seasons.  

Lefty

I've bought a lot of stuff on E-bay from Asian sellers. Never had a problem and it sure is hard to beat their prices, especially on bulk components. As far as your RF module, a lot depends on how well it is documented or if you have other reference material on it from other sources. Good documentation and examples will make or break a project using a unproven RF module.

Lefty

Well you can use any available PC terminal program to monitor the PC's comm ports. For Windows there is the built in hyperterminal program and there are a zillion free terminal programs available for downloading. These have many features and it would seem to me that you would just be reinventing the wheel to write your own. I use brey-terminal.

Lefty