Electric Speed Controls

I am not exactly sure what you have, but it sounds you can't connect the old to the new as it stands now.

Most older RC cars used a brushed motor which have two wires a positive and negative. The speed was controlled via either a resistor which basically had two or three speeds with fixed resistors, or by changing the duty cycle with a transistor which gives you continuous variability.

The motor you have which has three wires sounds like it is a brushless motor which is basically a 3 phase ac motor. You would need an Electronic Speed Controller with it that is made for a brushless motor. The ESC has an input for motor power, and three wires that output to the motor. The ESC also has an input that goes directly to the RC receiver and connects where you would normally connect the servo. Some ESC's also provide 5 volts to power the receiver.

Yes, it was a brushed motor that was on it, and the new one is brushless. The old motor was either on or off, there was no difference in the speeds.

This is the ESC:

The motor is as follows:

The PCB for the old rc car only has a positive and negative terminal.

I wouldn't connect the new ESC to the PC board, you just need to connect it directly to the battery (through your on off switch?), then connect the control signal to where the servo would go. The three wires go to the motor.

You should be able to find an ESC that will work at the voltage of the battery. You might want to check the speed and torque of the motor, to make sure it will be compatible.

It is to make an air powered RC car. The ESC and motor will work at the voltage of the battery. Do you want a piccy of the PCB also?

I don't think I need a picture of the PCB. Does this car have a separate receiver? or is this just a cheap single PCB board does everything car?

If the receiver is integrated into the PCB and the motor control was simply on off, then you are not going to be able to integrate this with an ESC. You will need to buy a separate radio transmitter and receiver.

You need an output that provides a variable control as meant for a servo to drive the ESC.

If you only want the motor to be off and on, then you could program a microcontroller to read the on off signal and send the correct signal to the ESC, but that seems like a lot of work for nothing to me.

It is a built in one. How would you connect the seperate transmitter/reciever to the board and to the servo?

Other than the speed of the motor and the steering what else do you need to control?

If you get a receiver for this, then I think you won't need the old circuit board. You will basically just be using the toy car for its mechanical attributes. For the steering, it depends on how it steers. If it has a servo already in place you can use that, if not you will need to replace whatever is there with a servo.

It has a servo already attached. The speed of motor and steering is all I need to control.

Sounds like you don't need the circuit board then, just make sure the ESC has a BEC (Battery Elimination Circuit) so it will provide the 5 volts necessary to power the receiver and steering servo.

Just a thought, do you have any ideas for the schematic for the micro-controller so the motor will only go on/off?

Would a 2 Ch old remote control helicopter PCB be better? It is 7.2v, but has 2 brushed motors.