Can It Be this SIMPLE? (the Off-Topic continuation)

[Mike_Lynch]

Luciano.
First, do I even want to know what someone was doing “Going Faster under the Table” ?
Secondly, thanks for those links, I wonder If I could getaway with placing TWO
Variable Resistors in the circuit and using a relay triggered by the “Turbo” button to
switch between them? I’ll have to look into that as a possible solution.

“Next year you can set an higher speed.”
Good Idea if I could expect this thing to last a year. See the section of my reply to Melanie regarding PLASTIC.
While I was out earlier today I stoped at a GoodWill Store and found the kids NEXT ride “Barbie” QuadRider,
( Almost Brand NEW, No battery charger, no big deal. ) $10.00 (USD) amazing what people here “throw out”.
YEA “Barbie”(purple, pink & white) a few cans of spray paint will take care of THAT foolishness. 8-)
TWO 12 Volt motors on this thing, one on each rear wheel.
Compared to the GO Kart it’s a MONSTROUSLY large thing.
Neighborhood kids on foot and small animals will need to LOOK OUT ! ! !

Mel,
“If I was a three-year-old, I'd want to experience the joys of burning rubber from a standing start...”
Yea me too, but that’s real BAD on the PLASTIC Gearbox, as a matter of fact except for the motor, batteries,
axels and a few bits for steering linkage, the WHOLE DARN THING is plastic, Even the hollow wheels.
I’m glad I’m NOT the one who paid close to $200.00 USD retail for it. Someone lost the original battery
charger and chucked it into the Salvation Army donation box. I paid $8.00 for the thing.

If he were MY kid instead of my Sister’s he would have been real bored with this thing by three years
old because I would have started him on it at 6 months, 8 months at the outside.
WE DON’T NEED NO STINKING STROLLER ! ! ! 8-)
He would be racing GAS (Petrol) powered Go-Carts by NOW.

“Why bother with a PIC with the associated problems of Power Supply and Motor noise etc etc?”
Why bother with a PIC? I’ve got them in the parts bin collecting dust. I guess the REAL answer to that
one is my personal PicBasic experience / educ-tainment, (education + entrtainment) something I want to
have the experience of “under my belt / in my bag of tricks”.

“Just a time-delay relay that enables operation of the turbo button a few seconds after power has been applied.”
The kid needs to learn the difference in speeds first hand, I believe he already has some concept of the fact that he
can’t drive “Flat Out / Wide Open” all the time from he and his Dad playing with slotcars & NASCAR Videogames.

Although I have NO doubt that this thing will spend 90% or more of it’s running time in 12 volt
“Turbo Mode” If a time delay relay is used then there is no driver control over which speed he is going.
Also if you look at the schematic notes I posted the circuit as it stands right now has a “Parental Override”,
a 12 Volt lockout, probably nothing more than a key switch scavenged from an OLD PC Case, wired in series
with the “Turbo” button in the event his parents feel the 12 Volts is too fast for the kid to have access to from the beginning.

I hope you were thinking something along the lines of a NE555 as a timer for that Time Delay Relay,
I haven’t looked HARD, but when I look at Digikey those things are in the $100.00 and up range

This is a LOW BUDGET project,
( Prices listed in USD)
Vehicle = $08.00 Salavtion Army Store
Batteries = $05.00 (each) 2 x 12 Volt 12 Ah local Electronics Surplus Store
PIC = $02.00 Had on hand in the parts bins
Relays = $??.?? Had on hand from YEARS ago when local parts retailer closed
Car Wash = $01.75 DIY Carwash High Pressure stuff, had to blast off the cobwebs & crud
Battery Charger = $??.?? Had a box of power supplies & high current wall warts on hand.
Wire & Switches = $??.?? Had on hand 10 & 12 AWG wire and switches left over from another project

Look on the kids face when he’s ripping down the driveway and finds the Turbo, = PRICELESS ! ! !

My Brother in Law and I have TALKED about adding RC Controls to one of the full sized
Power Wheels JEEP and sticking the kid in that so we can steer him where we want him to
go instead of where he wants to go. Don’t know if that will ever happen but I’m keeping my
eyes open for a free or cheap JEEP in good condition.

[Melanie]

When I meant a Time-Delay Relay on the turbo switch, I meant that the Relay contacts were is SERIES with the switch and not in parallel with it. i.e., until the Relay threw, the turbo switch was out of circuit. Only AFTER the Relay closed, only then the turbo switch could be pressed if desired.

This way, the Time-Delay Relay is simply connected across the Motor, so when power is applied to the motor, the Relay then times and then after a preset time period closes it's contact enabling the turbo button if so desired. If you take power off the motor, the Relay drops out ready for a new timing cycle.

A couple of transistors, a Capacitor and a splattering of Resistors and you've got your circuit for about $1, no PIC, no software, and pretty much supply voltage independant with no worries about having to generate a clean 5v supply for the PIC.

[Mike_Lynch]

Melanie,

Thanks for explaining what you meant. My first reaction was to ask for a schematic,
but I want to stir some brain cells and actually THINK about what it is you are describing.
(Amazingly Sad how rusty I am on this stuff these days, if you don’t use it you LOSE it.)
I’ll have to sit down with pen & paper to see what I come up with before I come BEGGING
and have to bother you for a schematic. 8-)

Thanks
Mike_L

[Archangel]

When my Daughter was about that age I bought her a Suzuki JR50 motorcycle which she rode exactly once. Too much power and she bailed off never to ride again. So here's a suggestion: install a 1/4 inch headphone jack on the rear of this vehicle, break the power connection and wire it through the jack. the plug that mates gets a string attached to Dad or Grandpa. short the inner to the outer conductor of the plug. when it's plugged in he has power, if it gets away from him, the plug pulls out and it stops. You could get creative and use a shorting type jack so instead of stopping it switches to low power. I doubt
Dale Earnhart JR's. first ride was souped up very much.

RULE 1, SAFETY FIRST (Especially with kids)
RULE 2. Go back to rule 1

[Acetronics2]

Hi, Joe

I see something ... a DC motor Torque is a major function of the drawn current ...

soooo, limiting the Max current is a fair way to achieve your goal.

Now how ??? ... Mosfets have an internal ON resistance ... so, using PWM, just measure the D to S voltage, during the ON state ( 100% will also work ...), exactly as with a shunt ...
A simple comparator will short the gate voltage to ground if overcurrent... and allow to easily trim the limit.

That's what used on Power speed regulators for Electric models ...

now, you DO NOT have PWM aboard ... so, just sample D/S Voltage , say @ 500 hz to 3 KHz ( match to the motor ). Limitation will then be smooth enough.

Using a PIC to slowly automatically increase the PWM rate will add the soft start function ... and you've what you want

AND the MOTOR is SAFELY DRIVEN ...

Alain