I was pointed out that this project lack details, so there it goes ;)
My little son loves trains, cranes, and everything that has blinking lights, especially police, fire trucks and ambulances.
This particular project has been put from parts lying around, with exception of the battery holder that I've ordered especially for this application.
One of the parts re-used is XD-YK04 that I've used loong time ago for another of my son's toy, that he grew up of it. Another thing I've decided to go "wireless" is the ease of the use (buttons on the top of the car are not accessible by little guy like that, and cables around such curious person are also recipe for disaster)