You might try here for ideas

It sounds like it can be done. First you need to find out what the tach needs for an input, what levels, speed and form. Then you can have the arduino output that to the tach. After you get that working then start on the control.

Here's one I've used. http://www.mulveyfamily.com/weather/Sensor_Grenade.doc

If AVG was doing that to their systems they were using it incorrectly or they got a bogus copy.

As you've found you click the message count then on the left there is a box with tabs. The second one is profile and the new box can have the headings clicked to access.

Nice work and excellent information. Thank you VERY much.
 

This is a good little board. I didn't see if it included a voltage regulator but it would not be hard to add if needed.

here's another good link.

I guess my first question would be what is the use of this in the robot? Could it be off until needed and then turned on and read then allowed to turn off again?

You might try here http://www.electro-tech-online.com/

I'd start by going out on the web and seeing what is already out there, no need (or market) for something someone else is doing already. Then put together a list of what you want it to do and how you want it to do that. Once you have a plan start looking for parts that will do the things on your list. Too many people start with the micro and then ask how do I do this with this part and sometimes the answer is "you don't"

I couldn't find a place to test my post. If there is one I'll use it next time.