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This is a great project but it sounds a little ambitious. I suggest stripping down to the bare minimum to make your kid have fun and adding new things over time

This is a great project but it sounds a little ambitious. I suggest stripping down to the bare minimum to make your kid have fun and adding new things over time. I am going through a similar line of development for my kid but I started with a cheap power wheels and decided to forego remote control to let him drive. I started putting him in the car at 13 months and he was able to control steering and acceleration himself and direct himself where to go at about 16 months. In time order my mods have been: 1. Soft start (R/C circuit, heat sunk MOSFET) 2. Replace lead acid with 18650 batteries 3. Reverse switch (they make these for big fancy power wheels, they just reverse the polarity to the motor) 4. Bluetooth remote kill switch (Lazybone - I don't recommend it, the ios app is crap) 5. Turbo button, adds a 18650 in series with the 2 other when the button is pressed 6. 2 batteries in the turbo button for a total of ~16v He drives very well himself now, with 2 big issues - it is hard to get him to pay attention to what's in front of him at all times and go slowly around pedestrians (that's where the remote stop comes in), and it's so fast now that I need to figure out how to add brakes (maybe I'll just move him to a real go kart with rubber wheels and mechanical brakes). But he's an excellent driver at just over 2 years old and people are always very impressed. Kids are capable of a lot more than we give them credit for.

mschuster91 9y ago
> and it's so fast now that I need to figure out how to add brakes Why not use electric brakes first? Take some high-load resistors, and use a high-current relay to switch the motor positive line from the 18650 controller to the resistor bank. For more fun, make a stepped resistor bank so you can control brake power.
- jerkstate 9y ago
  I've thought about doing something like that but I'm not sure if the plastic wheels and gear box can handle it, and I'm not sure how much more effort I want to invest in a limited platform. In the situations he's in now, anticipation is just as good as brakes; being able to see that he's going to run into a person or obstacle and slowing down is what I'm aiming for. In a "racing" situation, braking is necessary to slow down from high speed quickly in order to take a corner without losing traction, but the plastic wheels already have so little traction that we would exceed the performance envelope of the wheels before really getting much speed advantage out of it. Probably what I'll do is upgrade to a basic electric kart at the next birthday and leave this car as it is for Sunday driving and/or the next kid (it'll be easy to reduce the power again by reducing the number of batteries)
  - mschuster91 9y ago
    > I've thought about doing something like that but I'm not sure if the plastic wheels and gear box can handle it As long as the braking power does not exceed the power for acceleration, no need to worry (and you can always start with low braking load). Reversing the motor while the car is in motion is the dangerous thing.
_pmf_ 9y ago
> Bluetooth remote kill switch Wouldn't a Bluetooth keep-alive signal be better suited.
- jerkstate 9y ago
  man, I can't even find a kill switch with a decent iOS app to control it, I would love if there were more options, but since that isn't the primary focus of the project and I have a basically-working solution, I'm not going to put in the couple dozen hours it would take me to implement my own.
- pbhjpbhj 9y ago
  A BLE fence maybe?
jedberg 9y ago
I've been putting my three year old in her car to drive since she turned two, but she still drives like a drunk. How did you get him to understand that he has to keep the wheel pointed in a straight line to go straight?
- faitswulff 9y ago
  My 4yo never had a car like that, but maybe she thinks turning the wheel is "driving" ? I might try having her keep her hands off the steering wheel in a straightaway for a bit then gradually introduce turning. Or push it yourself if it's safer and slowly go through turns when she has the wheel pointed in the right direction. Good luck!
- jerkstate 9y ago
  It took quite a lot of sessions before he started understanding what to do; at first, he really preferred to push it from behind rather than sit in it. So I just kind of let him do that for several sessions and gently coaxed him into the car for a minute or two at a time. I felt like if I got frustrated he would get frustrated, and he would just reject the car altogether, so I basically let him do whatever he wanted with it at first. Once he was sitting in there and messing with the controls, I would run and dance around in front of the car to get him to chase me, which he thought was hilarious. As soon as he was able to go where he wanted and clearly enjoyed it, I thought he would be ready to listen to me tell him what to do, so we would take longer trips with a destination in mind, to the playground or to the drum circle. I would verbally tell him what to do (stop, go, turn left, turn right, reverse, forward, etc), and if he doesn't do it within a couple of seconds, I stop the car with the remote start and hunker down and explain to him what I wanted him to do and show him on the controls. If he continues to not listen to my instructions we take a few minutes time out out of the car and sit on a bench or run around or whatever. Anyways, keep trying! it's a lot of work but so much fun.
  - tomcam 9y ago
    Jerkstate, this is one of the best DIY posts ever. You sound like a great parent.
- 9y ago

mschuster91 9y ago

> and it's so fast now that I need to figure out how to add brakes Why not use electric brakes first? Take some high-load resistors, and use a high-current relay to switch the motor positive line from the 18650 controller to the resistor bank. For more fun, make a stepped resistor bank so you can control brake power.

jerkstate 9y ago
I've thought about doing something like that but I'm not sure if the plastic wheels and gear box can handle it, and I'm not sure how much more effort I want to invest in a limited platform. In the situations he's in now, anticipation is just as good as brakes; being able to see that he's going to run into a person or obstacle and slowing down is what I'm aiming for. In a "racing" situation, braking is necessary to slow down from high speed quickly in order to take a corner without losing traction, but the plastic wheels already have so little traction that we would exceed the performance envelope of the wheels before really getting much speed advantage out of it. Probably what I'll do is upgrade to a basic electric kart at the next birthday and leave this car as it is for Sunday driving and/or the next kid (it'll be easy to reduce the power again by reducing the number of batteries)
- mschuster91 9y ago
  > I've thought about doing something like that but I'm not sure if the plastic wheels and gear box can handle it As long as the braking power does not exceed the power for acceleration, no need to worry (and you can always start with low braking load). Reversing the motor while the car is in motion is the dangerous thing.

_pmf_ 9y ago

> Bluetooth remote kill switch Wouldn't a Bluetooth keep-alive signal be better suited.

jerkstate 9y ago
man, I can't even find a kill switch with a decent iOS app to control it, I would love if there were more options, but since that isn't the primary focus of the project and I have a basically-working solution, I'm not going to put in the couple dozen hours it would take me to implement my own.
pbhjpbhj 9y ago
A BLE fence maybe?

jedberg 9y ago

I've been putting my three year old in her car to drive since she turned two, but she still drives like a drunk. How did you get him to understand that he has to keep the wheel pointed in a straight line to go straight?

faitswulff 9y ago
My 4yo never had a car like that, but maybe she thinks turning the wheel is "driving" ? I might try having her keep her hands off the steering wheel in a straightaway for a bit then gradually introduce turning. Or push it yourself if it's safer and slowly go through turns when she has the wheel pointed in the right direction. Good luck!
jerkstate 9y ago
It took quite a lot of sessions before he started understanding what to do; at first, he really preferred to push it from behind rather than sit in it. So I just kind of let him do that for several sessions and gently coaxed him into the car for a minute or two at a time. I felt like if I got frustrated he would get frustrated, and he would just reject the car altogether, so I basically let him do whatever he wanted with it at first. Once he was sitting in there and messing with the controls, I would run and dance around in front of the car to get him to chase me, which he thought was hilarious. As soon as he was able to go where he wanted and clearly enjoyed it, I thought he would be ready to listen to me tell him what to do, so we would take longer trips with a destination in mind, to the playground or to the drum circle. I would verbally tell him what to do (stop, go, turn left, turn right, reverse, forward, etc), and if he doesn't do it within a couple of seconds, I stop the car with the remote start and hunker down and explain to him what I wanted him to do and show him on the controls. If he continues to not listen to my instructions we take a few minutes time out out of the car and sit on a bench or run around or whatever. Anyways, keep trying! it's a lot of work but so much fun.
- tomcam 9y ago
  Jerkstate, this is one of the best DIY posts ever. You sound like a great parent.
9y ago