I think the request was to determine the motor requirements to select a controller.
What voltage was the battery the toy used? A bunch of AAs or somesort of NiCad battery pack? Can you re-purpose that battery for this project?
Now charge the battery and connect it to a motor. It should spin. If you have a multimeter with a current range that has a scale up to a few amps, then use it to get a current rating. Please read the instruction on how to connect it, or you will fry the meter or at least its fuse. Get a rating for no load. Next get a current rating for when you stall the motor. Armed with the voltage, and the current rating, we might be able to offer you some advise on a motor driver.
One more thing(s): Do you want forward and reverse? Do you want speed adjust?
The reason i took it apart in the first place was because it sounded like a fun project and the battery was dead and replacements all seemed expensive but the battery doesn’t seem to have any useful info on it it was the tyco rc flex-pack
So a quick Google indicates 7.2V for a flex-pack. Depending on the chemistry, a replacement 7.2 pack will cost anywhere from 12 to 100 dollars. Add 20 for a charger. Using NiCads, these will often supply up to 20 amps for a short time.
So if this is a project you want to pursue, I would first pick a battery system in the 6 to 12V range. If you use PWM and limit the duty cycle to 7/12 you could use a 12V battery without damaging the motors. Next you still need the short circuit current to pick an adequate controller. You can get a rough idea what that will be my measuring the resistance across the power terminals. Using our good friend V=I*R we can compute I from V/R.
Ok i will check that Tomorrow but for now i know running between them is a disk capacitor labeled 104 and the motors will run of a 9v battery that is directly connected to it would getting a rechargeable 9v and running it off of that or would it be harmful to the motors or should i stick with 7.2v I’m new to the field of motor controllers lastly what is the 7/20 or something stuff you mentioned
That capacitor is there to filter out the spikes that the motor generates while running and to try to keep them from working their way back to the controller.
9v battery? Like a little square 9v battery? You do know that most rechargeable 9v batteries are actually 7.2v? And that those little batteries aren’t going to have enough capacity to do much of anything?
7/20 stuff?
You mean 7/12? That’s a ratio relating to the PWM duty cycle that you might drive the motors with if you used a 12v battery.
Type in “7.2v battery pack” into Google and see all the 6 cell NiCad battery packs that come up. Look to see what might fit your car and then find a charger. Something like this might be good" http://www.amazon.com/HR72-KIT-Volt-Nit … B00006JP8J
If you do not want a 7.2V pack and get a 12V battery from someplace like Batteries Etc then you simply need to limit the duty cycle of the PWM signal on the Arduino to something less than max. Now I have not done PWM on an Arduino, but on other chips, you need to set a register with a value that will set the duty cycle. If 1024 is the maximum, that set it for no more 1024 * 7 /12. Now some chips use a smaller number for a higher duty cycle. in that case is minimum in 1024, then set the register to no less than 1024 * 7 / 12.
A 9v transistor battery would likely run less than a few minutes. They jsut do not have the capacity (mAh) to power two motors under any sort of load. They where designed to provide a steady small current at “high” voltage to run a few transistors.
If $20 for a a battery is out of the question, than how are you going to afford a motor controller or an Arduino?
Did you click on the link I provided? $21.51 for a battery and charger. That was only my second try. I suspect if you look around a bit, you might get a pair even cheaper.
That looks like a good possibility. Same voltage, good capacity. Should work just fine. Now all we need is the motor stall current or at the least the motor stall resistance.
For a temporary fix until i can get to radio shack to get a better look at the battery should i use a nine volt
when measuring the current will i have to have 7.2 volts on it or could i use another voltage get the resistance plug in to v = ir the resistance and find the correct current so
x = 9v y = 7.2v a = current i = resistance
x = ai
find resistance at x using multimeter (or would i even need to hook up a voltage)
