It is a formula for disaster because if you screw up ANYTHING in your circuits you stand a VERY GOOD CHANCE of screwing up your computer. If you use an external power supply and you screw up something with your arduino and added components, there is a very high probability that only your arduino will suffer.

Arduino = Cheap,  Computer = expensive

The units I used were driven by a PLC (programable logic controller) and also by a PC. You could also use Mach3, a pc based CNC program to control them. With the Arduino you can use them just like a stepper motor.

One problem with high step counts is that it generally means you don't get much speed because there is a limit to how fast a given device can send the pulses. Fastest speeds with an Arduino would mean that you would have to go to Assembler.

A mechanical earth ground to the metal of the strain gage itself.  It is acting like an antenna. Not knowing what your local sources of RF noise are, it would be hard to say what might be inducing the noise. You could also try running the wires through some ferrite beads as well as twisting the wires from each strain guage. All are ways of reducing the level of interference. Shielding around the wires from the strain gages. Ground shield wires AT ONE END ONLY. Preferably the end closest to the amp.

Often on designs using analog I/O there is a separate ground used for the analog signals that does tie to the main system ground. The purpose is to prevent electrical current from flowing in the analog ground path and corrupting (adding noise) to the analog signals being brought back to or going out of the system. I have worked with Plasma cutting  and welding systems where this was very important because noise in the analog circuits could affect machine motion and produce quality problems with welds.

What you might do is make yourself a shield that has a socket for the ATtiny on it, along with the other connections necesary and then all you have to do is plug the chip in and mount it on your Arduino and program away. I made a board like that has sockets for an ATtiny2313/4313 and an ATMega328 328/P. I program my 2313s with the internal clock so the board needs nothing other than a couple capacitors to run the 2313, and it has a 16MHz resonator for the 328. If I added a jumper I could also program the 8 pin chips on the same board.

Pardonez mois, moi Francais es limite...

This part of the forum is primarily in english. If you go farther down you can find a section of the forum in other languages.

Is you chip running of an external crystal? or off the internal clock? It sounds like you compiled the program using a configuration that is expecting a 16Mhz clock, but it is actually running a 8Mhz clock.

Any hobby shops near you that have Model Airplane supplies? They have thins like small shaft collars that are made of brass, and brass plate. You could solder the shaft collar to a piece of brass plate and then (using the set screw in the shaft collar) mount the crank to the motor.

Hey guys - nice of you to offer useful answers and ideas to the question that was asked.... Try to be helpful, not just geniuses...

This is an industrial servo, not a hobby servo.

Easiest way to control the motor from Arduino is using the Step/Direction interface. It then becomes a fast stepper motor. Industrial servos typically have a max RPM of at least 3000RPM and some will run as fast as 5000PRM. The steps per rev and other parameters are all configurable and allow you to tune the drive for the specific application. Generally a servo motor will need to be geared down (40:1 to as much as 100:1) to give you a usable RPM range, but with a gear reduction comes a torque increase.

I built some automated welding machines and we used at least 4 similar servos (Yaskawa, Mitsubishi, Parker and Omron) which we used in Step/Direction mode.

You are experiencing something called SLIP. the tires do not have an absolute grip to the surface they are running on and when you turn and such they slip slightly.

As the previous poster stated - you are running in an open loop configuration with no feedback from the environment. You might try running on a grid with something attaches to you robot that can detect that grid. That would give you some position feedback that you could then use to correct for errors.

The old rule from the Army - Depends on the terrain and the circumstances.

If you reside in some places on the globe then you will have to charge low rates as that is what the local market can bear. In other places the rates seem astronomical, but the costs there are much higher. Rates here in South Texas are rather low, but there is little demand. In Southern California the costs are much higher so the rates are much higher. You also have to look at whether you are clearing any money at the end of these jobs. Enough to cover costs? or are you really doing it as a hobby?

In your loop you read the potentiometer every time through. If the Value of the analog input is above some value then assign 5 to a variable - steps. if the value of tha analog reading is less than the required value then assign 2 to the variable.

They were careful to not get much of a picture of the light reflected off the surface of their piece of glass/plastic, but what  it behaves like is a complex lens. You can see the image go in and out of focus as it is moved back and forth in front of the paper.

You have to provide the connections, the 6 pin ISP header is one example, and you can use the ArduinoISP sketch to use your Arduino board as a programmer.

TRIAC has the advantage of "ZERO CROSSING SWITCHING" which mean that the TRIAC turns off when the AC signal  (a sine wave) is at, or very close to zero volts. Means that there is little heat disipation in your switching device and little EMI to bother other devices.