⚡ eWelink ST-DC4 — WiFi + RF 4-Channel Inching / Self-Locking / Interlock Relay Module
A 4-channel WiFi + 433MHz RF dry contact relay module with three working modes: inching (momentary), self-locking, and interlock. Four independent relays — control up to 4 gates, garage doors, locks, or irrigation zones from one board. Dual control: WiFi via eWeLink app plus optional 433MHz RF remote for no-internet backup. Accepts DC 5–32V or AC 90–260V board power.
🔀 WiFi Inching Relay Range
⚡ Key Features
- 4 Independent Dry Contact Relays — four channels, each with its own NO/COM/NC output; control four devices from one compact board
-
3 Working Modes:
• Inching (Momentary) — relay closes briefly (~1s) then auto-opens; for gate/garage/lock triggers
• Self-Locking — stays on/off until toggled; for lights, pumps, sustained control
• Interlock — when one channel turns on, the other(s) auto-turn off; for motor direction control - WiFi + 433MHz RF Dual Control — connects to WiFi for eWeLink app control AND supports optional 433MHz RF remote for physical button backup (works even without WiFi)
- Dual Voltage Input — DC 5–32V or AC 90–260V board power; runs from gate motor DC, battery backup, or 230V mains
- eWeLink App — remote control, schedules, smart scenes, device sharing, group management
- Voice Control — Amazon Alexa, Google Assistant, IFTTT
- Manual Button — on-board button to switch working modes and test relays without the app
All four relay outputs are dry contacts (NO/COM/NC). The AC/DC power input only powers the WiFi/RF board — it does NOT pass through to the relays. Wire each relay's contacts across the trigger terminals of the device you're controlling.
🏠 4 Channels — Full Property Control
Full Entrance Setup
Ch 1: Pedestrian gate · Ch 2: Driveway gate · Ch 3: Garage door · Ch 4: Front door electric lock. One module = your entire property entrance is smart.
Irrigation Zones
Control 4 solenoid valves for different garden zones. Set schedules in eWeLink: "Water Zone 1 at 6am for 15 minutes, then Zone 2, then Zone 3." Inching mode triggers each valve.
Commercial / Multi-Gate
Complexes, office parks, and farms with multiple access points. Four relay outputs handle multiple gates and barriers from a single control point.
RF Remote Backup
Pair a 433MHz RF remote (like the RM433R2) for physical control when WiFi is down. Perfect for load shedding or internet outages — the RF remote works regardless.
📋 Technical Specifications
| Model | EACHEN ST-DC4 |
| Channels | 4 (independent dry contact relays) |
| Relay Output | NO / COM / NC per channel |
| Relay Rating | 10A 250VAC / 10A 30VDC per channel |
| Work Modes | Inching · Self-locking · Interlock |
| Protocol | WiFi 2.4GHz + 433MHz RF |
| Board Power | DC 5–32V or AC 90–260V |
| App | eWeLink (iOS / Android) |
| Voice Control | Amazon Alexa, Google Assistant, IFTTT |
| RF Remote | 433MHz compatible (sold separately) |
| Hub Required | No — WiFi direct |
🔄 SV vs ST-DC2 vs ST-DC4 — Which One?
| Feature | SV | ST-DC2 | ST-DC4 ★ |
|---|---|---|---|
| Channels | 1 | 2 | 4 |
| Protocol | WiFi | WiFi | WiFi + RF433 |
| Power Input | DC 5–24V only | DC 5–32V / AC 90–260V | DC 5–32V / AC 90–260V |
| Inching | ✅ | ✅ | ✅ |
| Self-Locking | ✅ | ✅ | ✅ |
| Interlock | ❌ | ✅ | ✅ |
| RF Remote | ❌ | ❌ | ✅ (433MHz) |
| Hub Needed | No | No | No |
| Best For | Single gate/garage | Gate + garage combo | Full property / commercial |
❓ Frequently Asked Questions
What's the advantage of the RF remote on this model?
Can each channel be in a different mode?
What's the difference between this (WiFi) and the Zigbee DC4?
Can I use it for irrigation?
Does it support Home Assistant?
🤝 Need Help? We're Here for You!
Visit Us
8 Wildebraam Street
Weltevreden Park, Roodepoort
Gauteng, 1709
4 Gates. 4 Channels. WiFi + RF Backup.
EACHEN ST-DC4 — 4-channel WiFi+RF dry contact relay · DC/AC dual voltage · Inching + interlock