Braking

I am a student working a project which requires me to be able to stop a car that is powered by a small hobby engine. The car is five by five and I was wondering how can I we the microprocessor to stop the car.

I am a student working a project which requires me to be able to stop a car that is powered by a small hobby engine.

That makes it go. What makes it stop?

The car is five by five

But, what color is it?

I was wondering how can I we the microprocessor to stop the car.

Perhaps a servo to apply the brakes.

Is their a way to cut the power

AFAIK, there are servo operated disk brakes available for model RC cars.

Is their [sic] a way to cut the power

Of course there is, there always will be. But unless you tell us what kind of engine this is (petrol with a carb? petrol with efi? electric motor? or or or?) nobody can help you.

Electric

Inches

Shorting the motor leads together (but removing power from them first) is one way to brake an electric motor. If you need more instant stopping power, you need to look at electric brakes.

An option may be electric brakes made for trailers:
http://www.etrailer.com/Trailer-Brakes/Dexter/23-27.html

wait... lol. 5x5 inches? Just use an H-Bridge with built in brake function. With that, you would send a HIGH to both forward and reverse inputs and it would disconnect power from the motor and short the leads together.

You're not giving us very much information.

However, you can stop the car without using brakes if you use internal motor resistance (electric braking). The arduino alone cannot do this, you will need to build a circuit to absorb the current coming back. If you have a dedicated motor controller, perhaps it will have the ability to do so.

And again, if you need even more stopping power, look for servo operated disc brakes as suggested (I didn't find any) or just build your own by creating a lever that will squeeze a hard pencil eraser against the axle when you add tension through a cable operated by a servo (or solenoid, or whatever.)

Can u explain in simpliar terms.

No. That's really as simple as it gets unless you gave us more information

If you're H-Bridge supports braking, you have an IN1 and IN2 on the H-Bridge. You set them both HIGH to brake. That's it. If it does NOT support braking, you will damage your controller by doing this. Most do and you haven't told us anything at all about what motor controller you are using.

The motor will coast a bit doing it this way before completely stopping, so if you need "absolutely must stop right now!" kind of braking, then you have to make a mechanism that you can control which creates enough friction to stop the axle. Surely you have seen brakes on a bike for example. Just do that.

Surely you have seen brakes on a bike for example. Just do that.

... and with a bit of imagination you could hook the brake cable to a servo.

But you're not going to get (much? any?) more help if you don't give some info.... like how the whole thing is hooked up right now. Circuit diagrams? Program code? Mechanical sketches / photos...