An old sliding gate got upgraded with electric motors - Rework after 7 years
The original automated sliding gate project, built in 2018, has been completely reworked after 7 years of use. While the motors and wiring remained the same, the control system was redesigned from the ground up.

V1 Performance & Lessons Learned

The original built system performed pretty reliable for 7 years, making daily life much easier. However, over time, a few issues and missing features became apparent:

Startup stress – Motors engaged too abruptly, wearing gears, racks and mounts
Relay wear – 12V relays degraded, causing unreliable operation
Cold start issues – Thickened gearbox grease in the winter prevented movement due to weak starting torque
EMI problems – Sparks from relays forced external PCB placement
Limited control – No acceleration and torque control, or overload detection
Missing safety features - insufficient light barrier, no locking mechanism

V2 addresses these with a custom PCB and VFD-based motor control, improving reliability and adding new features.

Old relay control and V1.0 control board

What’s New in V2

VFD-controlled motors instead of relays and capacitors
- Smooth starts
- Precise speed and torque control
- Overload detection
Custom PCB
- Isolated microcontroller from long cables & VFD noise
- Integrated RS485 interface
- Servo interface for gate locking
- Encoder support for precise position tracking
New features & planned upgrades
- Multiple Light barriers
- Overload detection
- Servo motors for locking the gate
- Actual position tracking using encoders

V2.0 Control box and VFDs during wiring process

Specification

Power supply: 230 V AC
Control Interfaces:
- Buttons on gate
- Buttons on control box
- Remote control (radio transmitter)
- Web interface
Open / Closing speed: adjustable from 0 to 2 m/s

Main control-box, housing the pcb and the inside control interface

Components

Mechanical

2x 3D-printed gear
2x Toothed rack
4x Custom end position damper
2x Custom guide roller

Motors

Power: 0.3 kW
Voltage: 400 V
Frequency: 50 Hz
Type: Three-phase asynchronous motor
Connection: Now VFD-controlled (previously capacitor-based)

Motor with broken 3d-printed gear after 7 years of use

Control System

Custom PCB with ESP32 microcontroller
Motor control via VFDs (instead of relays)
Sensors:
- Limit roller switches
- Photoelectric barrier (new in V2)
- Encoders tracking motor position
Servo-controlled locking mechanism (new in V2)
RS485 interface (new in V2)

2 VFDs for driving the motors + 12 V power supply in a separate box

Electrical Overview

The wiring of all components is documented in the following diagram:

Full Document: V2.0_wiring-plan.pdf

Control PCB

The custom PCB and firmware are available here: GitHub/gate_fw.

Designed specifically for this project, the PCB replaces the previous multipurpose board. It was CNC-machined for quick availability. The core features are: