OpenRC 4-Wheel Drive Go-Kart with Ackermann Steering

The model is inspired by Lego Go-Kart 1972:
https://www.toysperiod.com/lego-set-reference/technic/model/race/lego-1972-go-cart/

The custom electronics has been designed around the Esp32 processor. The controlling software can be found in github at:
https://github.com/projunk/RaceCarESP32

Two configurations are currently supported:

BR2830 850Kv motors with 2S Battery (NANO_TECH 4200)
see e.g.: https://www.amazon.in/Generic-Racerstar-BR2830-Brushless-Airplane/dp/B07PCMDCMF

Theoretical Top Speed: 113 Km/h

5010 360Kv motors with 4S Battery (MULTISTAR 4000)
see e.g.: https://nl.aliexpress.com/i/32479766898.html?gatewayAdapt=glo2nld

Theoretical Top Speed: 96 Km/h

The scale factor compared to Lego parts is 3.0

Printed Parts (already scaled):

BatteryHolderPlateStraps_MultiStar4000.stl (2x) or BatteryHolderPlateStraps_NanoTech4200.stl (2x)
ChairHolderHingePlate.stl
ElectronicsBrick.stl
ElectronicsPlate.stl
Plate_1x2.stl (2x)
Plate_2x8.stl
Rim_motor_2830.stl (4x) or Rim_motor_5010.stl (4x)
SlickTire_2830.stl (4x) or SlickTire_5010.stl (4x)
servo_connector.stl
technic_brick_ackermann_left.stl
technic_brick_ackermann_right.stl
technic_brick_motor_left.stl
technic_brick_motor_right.stl
technic_brick_servo.stl
technic_pin_with_friction.stl
technic_plate_toothed_end.stl (2x)
technic_plate_toothed_end_ackermann.stl
technic_steering_arm_motor_M8_left.stl
technic_steering_arm_motor_M8_right.stl

Printed Parts (to be scaled in slicer with factor 3.0):

HingePlate2Fingers.stl
MinifigTorch.stl (2x)
Plate_1x3.stl
Plate_1x4.stl (2x)
Plate_2x3.stl (4x)
Plate_2x4.stl (3x)
TileWithGrove.stl (2x)
technic_axle_3.stl
technic_axle_4.stl (2x)
technic_axle_6.stl
technic_axle_8.stl
technic_axle_pin_no_friction.stl (2x)
technic_brick_1x8_m4.stl (2x)
technic_bush.stl (4x)
technic_bush_toothed.stl (3x)
technic_connector.stl (8x)
technic_gear.stl
technic_gear_rack.stl
technic_wedge_belt_wheel.stl
technic_wedge_belt_wheel_grip.stl

Optional printed parts:

BodyTop.stl
Helmet.stl
Minifig_arm_left.stl
Minifig_arm_left.stl (mirror in slicer)
Minifig_body_bottom_plate_MultiStar4000.stl or BatteryHolderPlateStraps_NanoTech4200.stl
Minifig_hand.stl (2x)
Minifig_head.stl

Lego minifigure is based on:
https://www.printables.com/model/24298-lego-jo

Recommended Materials:

PLA (30% infill)
ABS (30% infill): axles,pins,technic connector, bushes, rims
Ninja Flex (10% infill): technic_wedge_belt_wheel_grip.stl, SlickTire_2830.stl, SlickTire_5010.stl

Hardware:

bearing MR128ZZ (6x)

Electronics:

4 in 1 ESC (30A)
Power distribution board
Acceleration sensor: MPU 6050
receiver (fly sky 3 channel FS-GR3E)
servo: MG 946R
neopixel Ws2812: (2x)
for other electronics parts see drawing: "Schematics_ESP32.png"

Software Features:

webservice which either connects to local network or creates its own accesspoint if local network cannot be reached
webservice shows telemetrics, speedo and settings. Settings can be updated on the fly and are saved
Acceleration sensor input is used to help steering
In case of taking a turn, the inner wheels are slowed down to help steering around a corner
LED string shows status (armed/disarmed) and indicates driving directions

Remarks:

a custom name can be generated for BodyTop.stl using the BodyTop.scad source file
print technic_wedge_belt_wheel_half.stl twice and glue parts together
print technic_wedge_belt_wheel_grip_half.stl twice and glue parts together
print technic_gear_half.stl twice and glue parts together

Alternatives for the glued “half” parts have been added that can be printed as a single piece:

technic_gear_rounded.stl
technic_wedge_belt_wheel_easy_printable.stl