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Save hello kitty!!!

qwerty123

May 10, 2010
2
Joined
May 10, 2010
Messages
2
Guys,
I need some help... I live in Memphis and last week we had a bit of flooding... we survived mostly unscathed but we lost the battery on my daughter's hello kitty four-wheeler... I was hoping someone could help me make a switch-mode buck converter on a bread box... but not sure how... I plan on using 18vdc Ryobi batteries (Lithium or NiCd i have both) because I have a ton of them...
your help is appreciated... I know I could buy something pre-made but I wouldn't learn anything fun from that....

...and my 2y/o says thanks too guys!!! :D
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
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25,510
What voltage does hello kitty require? And at what current?

SMPS on a breadboard is probably a very poor idea, but with a suitable PCB is should be OK.

I'd try something like an LM2576 or similar. Remember that they're not as forgiving as 3 terminal linear regulators, but the datasheet does suggest the correct inductor and layout.
 

qwerty123

May 10, 2010
2
Joined
May 10, 2010
Messages
2
What voltage does hello kitty require? And at what current?

SMPS on a breadboard is probably a very poor idea, but with a suitable PCB is should be OK.

I'd try something like an LM2576 or similar. Remember that they're not as forgiving as 3 terminal linear regulators, but the datasheet does suggest the correct inductor and layout.

6V 4.5Ah from the battery... I can get my brother-in-law to make the circuit board for me one day next week... your help is appreciated!!!
 

NickS

Apr 6, 2010
367
Joined
Apr 6, 2010
Messages
367
If you can get somebody to make a board for you then go all out. Don't just convert the voltage down but drive the motors with PWM for purpose of ramping power in and out of those poor motors and plastic gears. You could even monitor for high current situations(stuck against the curb at full throttle) and reduce drive power to save your hardware.
 
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