BLDC Blower Controller

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tehvofka

Please choose option 2, but with a slight correction: we are using an onboard 5x20mm glass cartridge fuse holder (THT), not a blade fuse. Please add this THT fuse holder to the schematic and PCB near the input terminal.
After adding it, proceed with compacting the board to under 80x80mm following the previous placement rules.
Additionally, please add four 3.2mm mounting holes (suitable for M3 screws) in the four corners of the PCB. Place them about 3-4mm inward from the board outline, and ensure there is enough clearance around them so the screw heads or standoffs won't short any traces or components.

flux

I’ll add a THT 5×20 mm fuse holder and M3 mounting holes, insert the fuse into the 18 V input path, resize the board below 80×80 mm, compact-place everything to the enclosure edges, then reroute and verify.

flux

The fuse is now electrically in series, the compact Nano and flyback footprints are in place, and the board is resized to 79×79 mm with four 3.2 mm corner holes. I’m running the dense placement pass now.

flux

I’m blocked because the project has no available ACUs, so I cannot complete the remaining layout operations.
Completed:
  • Added and wired the THT 5×20 mm fuse holder in series with the battery input.
  • Resized the board to 79×79 mm.
  • Added four 3.2 mm corner mounting holes with 7 mm screw-head clearance envelopes.
  • Replaced the oversized Nano and flyback-diode footprints with more compact THT alternatives.
  • Removed the previous routing in preparation for rerouting.
Remaining:
  • Resolve overlaps from the first dense placement attempt.
  • Confirm all components and mounting-hole clearances fit within 79×79 mm.
  • Reapply the 2.8 mm high-current rules to BAT_RAW.
  • Auto-route and run final ERC/DRC checks.
  • Regenerate Gerber/drill files afterward.
Additional ACUs are required to continue execution.
Resume compact layout
Show overlap issues
Check fuse clearance
Run final checks
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Files

Schematic

Layout

Preview

Project Specification
Project Overview
Status: Draft
18 V battery-powered BLDC blower control board controlled by an Arduino Nano. The board switches the blower's 18 V supply through an IRF4905 P-channel MOSFET cutoff circuit driven by a 2N2222 NPN transistor and provides a 5 V logic rail from an LM2596 buck converter module.
Intended Use
Prototype controller board for an 18 V BLDC blower powered from an 18 V battery. Intended for R&D/prototyping use with an Arduino Nano as the logic controller.
What the Device Should Do
  • Accept 18 V battery input.
  • Provide high-current switched 18 V output to the BLDC blower, up to 5 A.
  • Generate 5 V from the 18 V battery using an LM2596 buck converter module for the Arduino Nano and 5 V peripherals.
  • Let Arduino firmware enable/disable blower power via a P-channel MOSFET high-side cutoff.
  • Monitor battery voltage through a 100 kΩ / 33 kΩ divider into an Arduino analog input.
  • Read a 10 kΩ linear potentiometer.
  • Drive a 5 V active buzzer.
  • Drive red and green status LEDs through 220 Ω resistors.
Main Features
  • 18 V battery input connector.
  • 18 V blower output connector.
  • IRF4905 P-channel MOSFET high-side cutoff with 2N2222 gate driver.
  • LM2596 18 V-to-5 V buck converter module footprint/connection.
  • Arduino Nano header/module interface.
  • Battery ADC divider, potentiometer input, buzzer, and red/green status LEDs.
  • High-current 18 V PCB routing target: 5 A.
System Architecture
Diagram



  
    
  
  
    
  

























18V Battery Input
IRF4905 High-Side Cutoff
BLDC Blower Output
LM2596 Buck Module
5V Logic Rail
Arduino Nano
2N2222 Gate Driver
100k/33k Battery Divider
10k Potentiometer
5V Active Buzzer
Red/Green LEDs
Hardware Subsystems
Power Input and High-Current Path
  • Battery input: nominal 18 V.
  • Blower switched output: up to 5 A.
  • P-channel MOSFET high-side cutoff using IRF4905 TO-220.
  • High-current traces and connector ratings must be sized for at least 5 A.
5 V Logic Rail
  • LM2596 buck converter module steps 18 V battery input down to 5 V.
  • 5 V rail powers Arduino Nano 5V pin, active buzzer, potentiometer reference, and LED indicators.
Arduino Nano Control
  • Arduino Nano controls MOSFET cutoff, buzzer, red LED, and green LED.
  • Arduino analog inputs read battery voltage and potentiometer wiper.
User Interface
  • 10 kΩ linear potentiometer across 5 V and GND with wiper to analog input.
  • Red and green LEDs with 220 Ω series resistors.
  • 5 V active buzzer controlled by a digital output.
Interfaces and Connections

Table

InterfaceConnection
Battery input2-pin high-current connector: BAT+ and GND
Blower output2-pin high-current connector: switched 18 V and GND
Buck moduleVIN+, VIN-, VOUT+, VOUT-
Arduino Nano5V, GND, ADC and digital GPIO connections
Potentiometer5V, analog wiper, GND
BuzzerArduino GPIO output and GND
LEDsArduino GPIO outputs through 220 Ω resistors to LED anodes, cathodes to GND
Power and Runtime Expectations
  • Nominal battery: 18 V.
  • Main load: BLDC blower up to 5 A, approximately 90 W peak at nominal voltage.
  • 5 V logic current is assumed below 500 mA unless the Arduino/peripherals require more.
  • Runtime depends mainly on battery capacity and blower duty cycle.
Power Tree and Power Budget

Table

RailLoadEstimated Current
18 V switchedBLDC blowerup to 5 A
18 V input to buckLM2596 input for 5 V railapprox. 0.1-0.2 A for light Arduino loads
5 VArduino Nanoapprox. 50 mA typical, higher with USB/peripherals
5 VBuzzerassumed 30 mA peak
5 VRed LED + 220 Ωapprox. 13 mA
5 VGreen LED + 220 Ωapprox. 13 mA
5 VPotentiometer 10 kΩ0.5 mA
5 VBattery divider load from 18 Vapprox. 0.135 mA from battery
Manufacturing and Assembly Expectations
  • Prototype-oriented board.
  • IRF4905 requested in TO-220 package.
  • High-current connectors and copper must be selected/laid out for at least 5 A.
  • Trace width should be refined based on copper weight, temperature-rise target, and layer stackup before routing/manufacturing.
Firmware-Relevant Hardware Requirements
Initial Arduino pin assignment:

Table

FunctionArduino Pin
Battery monitor ADCA0
Potentiometer wiper ADCA1
MOSFET cutoff enableD9
Buzzer driveD6
Red LEDD4
Green LEDD5
Physical Design Expectations
  • Board size not specified; assume compact prototype board with high-current connectors on one edge and logic/UI separated from power switching.
  • Keep high-current loops short and wide.
  • Place IRF4905 with copper area for heat spreading.
Important Design Decisions
  • Use high-side P-channel cutoff so the blower ground remains common with logic ground.
  • Use 2N2222 to pull the P-MOSFET gate low for ON; gate pull-up to battery positive keeps MOSFET OFF by default.
  • Add R10 as a series resistor in the Q2 collector / MOSFET-gate pull-down path, plus a gate-source pull-up, to limit zener clamp current and define the off state.
  • Divider ratio updated to 22 kΩ / (100 kΩ + 22 kΩ), mapping a 21 V fully charged Makita pack to about 3.79 V at the Arduino ADC.
Assumptions
  • The BLDC blower has its own commutation electronics and only needs switched DC power; this board is not a 3-phase BLDC motor driver.
  • Arduino Nano is powered at its 5V pin from the buck module output.
  • Buzzer is an active 5 V buzzer suitable for direct GPIO drive or low enough current for the selected Arduino pin; if not, add a transistor driver.
  • No battery charging circuitry is included.
  • User will use an external inline 10 A blade fuse. Onboard additions include a P6KE20CA TVS across BAT_18V/GND and a 1N5825 flyback/freewheel diode across the blower output. No onboard fuse is included.
Change Notes
  • Initial draft created from user requirements on 2026-07-20.

  • Project Overview

  • Intended Use

  • What the Device Should Do

  • Main Features

  • System Architecture

  • Hardware Subsystems

  • Power Input and High-Current Path

  • 5 V Logic Rail

  • Arduino Nano Control

  • User Interface

  • Interfaces and Connections

  • Power and Runtime Expectations

  • Power Tree and Power Budget

  • Manufacturing and Assembly Expectations

  • Firmware-Relevant Hardware Requirements

  • Physical Design Expectations

  • Important Design Decisions

  • Assumptions

  • Change Notes