soft start dc motor????

I have a motor that takes drives a wheel with a 3.6 volt dc rechargable battery pack. The problem is, when I switch the motor on the wheel spins out with the 3.6 volts. I was hoping there is a way to have the motor start off slowly and speed up. this has to do it on its own, no other manual switches or remotes can be used. If there is such a thing as an automatic potentiometer or something of the sort. that would be great. please help. Thank You

Is it possible just to put a little gearbox on it to reduce the speed of the motor? Alternatively I would suggest this problem is easier to solve with a few mechanical mods, like increasing the tension on the wheel to increase driving friction, or possibly cutting a starting groove to give the wheel more purchase when starting off. Is slip a problem when the wheel is running at speed?

it is impossible to put a gear box in the space needed

and I cannot have any slip

What is the interface between the wheel and the surface you are driving?

What you could possibly do is use a relay timer to add a resistance in series on startup. A little experimentation with resistors could allow it to start at 1/4 to 1/2 speed then transition to full speed.

I have read the original post several times trying to figure out the application. It sounds like an RC car type application but you said remotes can not be used.

With that in mind if the device needs to be small it may be possible to construct something simple but effective using a 555 timer.

What you need is an Inrush Current Limiter. It's a NTC (Negative Temperature Coefficient) Thermistor. It starts out at a high resistance, and drops as it warms up. You'll need to do some research to choose the proper one for your design. Start here:

http://content.honeywell.com/sensing/prodinfo/thermistors/inrush.asp