Timer for a toy car

[Mike 232]

Hi , this is my first time posting . I'm glad I found this website . I have a little toy car my kids like to play with . I don't have a picture of the car right now but it's a Road Rippers Street Screamer Mustang . It's about 4 inches long powered by what looks like a DC 130 motor . When you hit the buttons on the roof it does some back and forth action and then it goes . I just picked up a Dodge Viper of the same model and it's tough to drag race them when they do all that crazy stuff before taking off . The box says the longer you hold the button before releasing the faster it goes but I haven't found that to be true . It is now powered by 3AAA batteries . I would like to have some kind of timer system where I just hit the button , it delays a second or 2 then goes full speed for 5 seconds . I will probably up the battery power too , not really caring about motor longevity . Another thing I noticed is it has a capacitor across the terminals of the motor , not sure why . I know I could buy a small cheap Rc car , but we will learn something doing this project and the kids can drag race them down the hallway . Thanks for any info . Sorry for the long post .

 

[AnalogKid]

The capacitor across the motor terminals is probably there for noise control. Without something more to go on there is no advice. Photos of the guts would help, as would any text or markings on integrated circuits.

ak

 

[Mike 232]

Thanks , I'll take a picture as soon as I can . But I was thinking of building a timer/ button system from scratch . I think I might need a 555 timer ? But I have no idea how to set it up ? I guess I eventually want to run a 9 volt alkaline battery or a small lipo battery to power the motor .

 

[shrtrnd]

The designers probably included a circuit to do the fancy initial start-up routine for one of two reasons.
1) To make the action look interesting, or
2) To disconnect the forward/reverse gear action, to ensure that the car will engage the forward gear and start moving the car forward when you press that command button.

 

[Audioguru]

The datasheet of an LM555 or NE555 shows that its minimum supply voltage is 4.5V. A Cmos 555 is an ICM7555, LMC555 or TLC555 has a minimum voltage of 1.5V or 2V but their output current is low.

A transistor to switch the motor circuit on and off will drop the voltage. A Mosfet as a switch might need an input of at least 4.5V.

AAA alkaline battery current is 3 or 4 times higher than 9V alkaline battery current. Sine the voltage is higher then the motor current will also be higher. Your will need to replace the 9V battery every few minutes to keep the speed of the car high enough.