Carkit

CarKit – Because Your RC Car Needs a Brain

A Swiss-Army-Knife Control Board for DIY RC Chaos™

(You bring the chassis. It brings the brains.)

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Renders

Visuals because everyone loves eye candy.

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BOM

All the silicon, blinkenlights, and screw-down bits live here.

Main characters:

• MCU: ESP32-C3-WROOM-02
• Motor Driver: DRV8876 dual DC motor driver
• 5 V Regulator: LM2596SX-5.0 buck converter
• 3.3 V Regulator: AMS1117-3.3 LDO
• RGB LEDs: SK6812 addressable LEDs (x4)
• Power LED: XL-2012UVA
• Inputs: USB-C, Barrel jack, and screw terminal power
• Connectors: KF301 5.0 mm terminal blocks + 2×3 SMT headers
• Misc: Buttons, buzzer, pull-ups, decoupling caps, and the usual supporting cast

(See BOM.md for the full part list, values, and LCSC links.)

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What is this?

This is a do-it-all RC control board built around an ESP32-C3, designed to handle basically everything you might want on a DIY RC car:

• 2 DC motors with PWM (think: drive + steering/turning)
• 1 BLDC motor output (via external ESC)
• 1 servo motor output
• Bluetooth gamepad support (so you can use almost any Bluetooth controller)
• Multiple power input options (USB-C, barrel jack, or raw battery via screw terminals)
• 4 RGB status LEDs for connection, mode, and “because RGB”
• On-board buzzer for beeps, alerts, and dramatic startup tones

It’s meant to be the drop-in brain for “I duct-taped this together but now I want it to drive nicely” RC builds.

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Features

Motor Control

• 2× DC motor channels
  • PWM control for speed
  • Direction control via DRV8876
  • Great for drive + steering or tank drive* setups
• 1× BLDC channel (signal)
  • Standard PWM output to an external ESC
• 1× Servo output
  • For steering, camera gimbals, or cursed animatronics

_{*While the board supports tank drive it wasn't built for it.}

Power Options

Because every DIY RC build uses a different battery, obviously.

• USB-C (5 V)
  • For bench testing, firmware dev, and flexing modern ports
• Barrel jack
  • Perfect for 9 V batteries or standard DC wall adapters
• Screw terminals
  • Bring your own LiPo / battery pack
• On-board power handling:
  • LM2596SX-5.0 buck converts input to 5 V
  • AMS1117-3.3 steps 5 V down to 3.3 V for the ESP32-C3
  • Bulk and decoupling caps sprinkled everywhere to keep noise and brownouts away

(Dont feed the board anything over 36V, I would recommend staying under 24V)

LEDs & Buttons

• 4× SK6812 RGB LEDs
  • Can show:
    • Connection status (paired / searching / sad)
    • Board mode (e.g. normal, config, debug)
    • User-defined patterns (rainbow, brake lights, underglow, whatever)
• 1× Power LED
  • Because sometimes you just need “is this thing on?”
• Tactile buttons
  • For reset and boot functions (programming)

Connectivity & IO

• ESP32-C3 MCU
  • Wi-Fi + Bluetooth LE
  • Extra GPIOs broken out via 2×3 SMT headers for expansion
• Screw terminal outputs
  • For motors, power, and other “don’t-come-loose” connections

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Motor Channels Overview

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How It Works

At a high level:

1. You power the board via USB-C, barrel jack, or screw terminals.
2. The LM2596 generates a solid 5 V rail, and the AMS1117 creates the 3.3 V rail for the ESP32-C3.
3. The ESP32-C3 runs your firmware:
   • Reads input from a Bluetooth controller
   • Outputs PWM and direction signals to the DRV8876 for the DC motors
   • Generates PWM for the BLDC ESC and servo
   • Drives the SK6812 RGB LEDs and buzzer to show status and vibes

All the “annoying parts” (power, drivers, IO protection, connectors, etc.) are on the PCB, so you can focus on mechanical design.

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Using a Bluetooth Controller

The exact firmware and controller mapping is up to you and some basic stuff is included, but the general idea is:

1. Flash your ESP32-C3 firmware that:
   • Pairs with a Bluetooth gamepad / controller
   • Maps sticks/triggers/buttons to motor speeds and steering
2. On startup, the RGB LEDs can:
   • Pulse / chase while waiting for a controller
   • Turn solid once connected
3. Drive your RC car like a normal RC car, but with way more flexibility and hackability.

(You can map “A” to beep the buzzer. You absolutely should.)

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RGB LEDs

Because a control board without RGB is just morally wrong.

Possible roles for the 4 SK6812 LEDs:

• LED 1 – Connection status (Bluetooth)
• LED 2 – Mode indicator (normal / config / debug)
• LED 3-4 – User bling (animations, underglow, warnings, etc.)

Or ignore all that and just run full rainbow vomit. No judgment.

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Why?

This board exists for that moment when you’ve got:

• An RC chassis
• Some motors
• A pile of batteries
• And zero desire to reinvent “basic motor control + power + Bluetooth” again

It’s meant to be the one board that handles:

• Motors
• Power
• Input
• Feedback

…so you can just design something cool and let this handle the boring electronics.

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Contribute

Have ideas? Want a new connector, mode, sample firmware, or just want to roast my layout?

• Open an issue
• Submit a PR
• Or just yell at me on GitHub with suggestions

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Disclaimer

This project is open-source, powered by vibes, and tested mostly on my own questionable hardware.

If you:

• Overvolt it
• Reverse the battery
• Strap it to a rocket
• Or send 48 V into something that wanted 5 V

…and it smokes, explodes, or develops sentience, that’s entirely on you.

Happy hacking!