First Build: Critique on my ride in car with buttons and noises!

Hi everyone!

So this is my first arduino build EVER and first delve into circuits and everything.
I'm pretty happy with my design and test build, but just after a critique/advice plus any ideas if you have them.

Build Concept:
I've bought a second hand Cozy Coupe plastic ride in car andpulled it apart.
I am respraying it and physically modding it to be a 1993 Turtle Van.

I am adding buttons and sensors to play various TMNT sound effects.

I originally started just wanting push buttons but have advanced past that in testing.

Current Parts

I have purchased a 16mb Audio FX with inbuild 2w amp from Adafruit.
I'm also using an Arduino UNO

I have an ultrasonic Sensor

2 x 8 Ohm (max 20w) speakers.

5 button switches.

USB powerboost 500c for lithium battery recharging

3.7V lipo 2400mah battery

Current Setup

Now i don't know the app to use for sketches however the setup is pretty basic and on the breadboard everything works. (havent added the battery part yet, just running off USB power through UNO)

  • The UNO will be powered by the 5v supply from the Lipo powerboost

  • UNO Digital out and in pins used for the ultrasonic write/read

  • This sends a message to play an AudioFX sound

  • The audio FX board has 5 active buttons that just work using the audiofx pins.

So in reality the car will have a bunhc of pushbuttons plus the sensor on front so if he is 30cm from running into a wall, Leonardo shouts out "Watch out".

Other plans:

I have ordered an accelerometer/gyro.
I'm going to biuld this in (after some testing!) so if the car does a wheely (angled up) or is going down a step (angled down) then it will play some kind of "watch out" sound clip.

Things I'm not quite sure about! - HELP!
Will this battery be enough to supply for this car? I really haven't looked into the math or even know how to approach this.
The idea is that it can be charged via usb so i can plug the car into the wall and recharge but it needs a decent amount of use each time not just 10 minutes!

I want to do something like this to auto-off the whole board:

  • Have a momentary button that "turns on" the arduino

  • If gyro senses 0 movement then ill have some kind of integer which will get "NotMoving = NotMoving +1 "

  • if there is movement then NotMoving == 0

  • If notMoving == 1000 then TURN OFF ARDUINO..

Is this possible? The idea is that in my code i have a Delay which then if every loop will check if the car has moved. if it is still the same then this will tick up and then i can just decide that if this = 5minutes then the arduino turns off...

Anyway, I'm keen to look into this but is this even an idea?

Is this the kind of direction I should be headed??

Finally, is this UNO a bit of an overkill to just trigger the audiofx by pin13 load as well as using the ultrasonic sensor??? Is there a smaller more basic board i should just use?

Sorry for all the questions, but they all kind of mould into the same big question and general critique of my first experiment!!

wow should i even be using an Arduino Uno,,, Maybe I should use something like the Adafruit Metro mini!?

I guess all i need is 3 digital out and one digital in.
I'm not really using it for much more... but I'll also be adding the accel/gyro too..