Hi all, I have been lurking around these forums for a while now, finally created an account because I require some guidance on building a circuit to suit my needs, it's a simple-ish concept but I am having trouble accomplishing this.

I am currently building a car where it must travel forward until reaching a wall, pause for 10 seconds and then reverse the motor to go back and stop where it originally started. As far as the mechanical design goes, the car is pretty much done apart from this problem I have with designing a circuit to suit my specific needs.

Here goes:
I will have a 3V battery supply, it needs to have a master switch to turn on the whole circuit.
Once the circuit is powered, an LED must turn on and the motor must move the car forward until it reaches a wall, triggering a form of limit switch which will stop the motor.
Once it stops at the wall it will need to pause for 10 seconds and a second LED must activate as well as a buzzer.
After the 10 seconds is up, the 555 timer will trigger the sdpt/dpdt relay, the buzzer and second LED will deactivate and I will need the motor to run in reverse until it reaches the starting point where I will need a form of kill switch to stop the car entirely.

As far as I am aware, I need a 555 timer to accomplish this but I am open to other suggestions such as a simple RC delay system.
I understand this is a rather peculiar problem, many thanks to anyone who may be able to help guide me in a right direction or providing a basic circuit to build on.

 

Really, this project seems to be very much suited for a small processor. Multiple outputs required as well as at least one timer, and a sensor switch. Unlike many other projects, this one is best served by a processor and some code.

 

I am currently building a car where it must travel forward until reaching a wall, pause for 10 seconds and then reverse the motor to go back and stop where it originally started.

That's easily done using a 555 timer going forward and reverse but what steers the car so that it will return to the starting point?

 

That's easily done using a 555 timer going forward and reverse but what steers the car so that it will return to the starting point?

What makes the implementation more complex is the two LEDs and the time delay. forward and back could even be accomplished using a DPDT maintained contact switch, triggered by reaching the wall , and then reset to off upon hitting the return stop. Those additional requirements add complexity.

 

I will have a 3V battery supply, it needs to have a master switch to turn on the whole circuit.

What type of battery and capacity?

 

Version #1:
Sw2 and Sw3 are momentary lever switches
Sw2 is mounted on the front bumper and Sw3 on the rear bumper.
Initially the car is placed against a backstop.
When power switch Sw1 is ON IC1 will turn mosfet M1 ON applying power to the motor and the car moves forward.
When the car arrives at the wall Sw2 will close turning OFF M1 and start the 10 second delay timer.
Mosfet M2 turns ON activating LED2 and the buzzer.
At the end of the 10 second delay mosfet M2 shuts OFF. IC2 turns ON mosfet M3 activating the relay.
An instant later M1 turns back ON and the car moves in the reverse direction.
When the car reaches the backstop Sw3 opens and shuts OFF M1 killing power to the motor.
Sw2, Sw3

 

Microprocessor Version #2: