Introduction

Hello Guys, My name is Akash Vishwakarma, As being an engineering Student I am fond of making things from scratch. When I was in my 1st Year I have decided to fly my quadcopter by the end of the 1st Year and I did it. In my DIY drone project, one of the most important and satisfying achievements was building my own coreless motor driver circuit using MOSFETs and Schottky diodes. Most hobbyists use commercial ESCs, but I decided to design a lightweight, custom motor driver for each of the 4 motors in my drone.

Components Used

MOSFET: AO3400
Compact, efficient N-channel SOT-23 MOSFET rated at 30V, 5.2A, Rds(on) ~27mΩ — perfect for high-speed coreless motors.
Schottky Diode: SS14
Protects the circuit from reverse voltage spikes.
10kΩ Pull-down Resistor
Prevents the MOSFET gate from floating and false triggering.
Additional Tools and Materials:
- Universal PERF PCB Board (2x8cm)
- Jumper Wires
- Anti-static ESD Strap for safe soldering

🛠️ Circuit Design (Per Motor)

Each motor used this circuit configuration:

Gate → NodeMCU PWM pin (D5–D8)
Source → GND
Drain → Motor Negative Terminal
Motor Positive Terminal → 3.7V LiPo Vcc
Schottky Diode → Cathode to Vcc, Anode to Drain
10kΩ Resistor → Between Gate and Source

This was replicated for 4 motors — each on a separate PWM line.

⚠️ Challenges & Solutions

Issue	Solution
Floating gate triggering motors	Added 10kΩ pull-down resistors
Reverse current voltage spikes	Installed SS14 Schottky Diodes
Minor heating on MOSFETs	Used optimized PWM and heatsinking

💰 Sample Cost Breakdown

Component	Qty	Price (INR)
AO3400 MOSFET	10	₹40.00
SS14 Diode	10	₹16.60
10kΩ Resistor	15	₹10.35
Universal PCB	1	₹10.00
Jumper Wires	40	—
ESD Wrist Strap	1	₹40.00

Building My Own Coreless Motor Driver for DIY Drone using Mosfets and Diodes.

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