🛠️ Why Did My Garage Door Remote Range Drop After Installing a Shelly?
🛠️ Why Did My Garage Door Remote Range Drop After Installing a Shelly 1?
Adding smart control to your garage door motor is a great way to blend convenience with automation. But what happens when that clever addition unexpectedly kills your remote control range? If you've added a Shelly 1 to your garage motor and suddenly your 433 MHz remote only works from 2–3 metres away, you're not alone—and you're not going crazy.
Here’s what’s really going on.
🔍 The Symptom
After integrating a Shelly 1, powered via a 24V DC wall wart, into your garage door motor's control circuit, you noticed a drastic drop in 433 MHz remote range:
- Before Shelly: Remote worked 10+ metres away
- After Shelly: Range dropped to < 3 metres, sometimes needing to be right next to the motor
That’s a massive and very noticeable degradation in performance. But why?
⚡ The Cause: RF Noise from Power Supplies
The root cause is electromagnetic interference (EMI)—specifically radio frequency interference (RFI)—being emitted by the switch-mode power supply (SMPS) in your 24V DC wall wart.
Switch-mode power supplies are efficient and compact, but they generate high-frequency noise, especially if poorly filtered. This noise radiates into nearby wiring and components, especially long unshielded wires, turning them into antennas.
📡 Why This Affects 433 MHz
Your garage door motor has an onboard 433 MHz receiver. These receivers are:
- Highly sensitive (by design)
- Usually not shielded
- Often placed near wiring or PCB traces that can act as antennas
When you connect the Shelly 1 and wall wart, you’re potentially introducing:
- High-frequency switching noise into the DC ground
- Conducted noise along wires connecting
SW/GND - Radiated noise near the receiver module
All of these can swamp or confuse the 433 MHz signal, causing the receiver to miss or misinterpret the signal from your remote.
✅ The Solution
Here are a few practical ways to fix or at least greatly improve the issue:
1. Use a Linear Power Supply (If Available)
If you can find a linear 24V DC power supply, use that instead of a cheap SMPS wall wart. Linear supplies don’t produce switching noise.
Downside: Linear supplies are larger, less efficient, and harder to find in 24V.
2. Try a Higher Quality SMPS
If you must use a switching supply, invest in one with better filtering and EMI suppression. Look for:
- CE/FCC compliance
- Metal casing (for shielding)
- Internal EMI filters
3. Add Ferrite Beads or Chokes
Install clip-on ferrite beads around:
- The 24V DC power cable
- The wiring from
Shelly SW/GND - The AC input side of the wall wart (optional)
This helps suppress high-frequency noise from radiating or conducting into nearby electronics.
4. Physically Isolate the Power Supply
Move the wall wart and its wiring away from the motor housing and 433 MHz receiver. If possible, place the power brick further from the motor and use a shielded cable to carry power to the Shelly.
5. Try an Optocoupler or Relay Interface
Instead of directly bridging the motor’s SW/GND circuit with the Shelly’s dry contact, use a low-EMI optocoupler board or relay in between. This electrically isolates the Shelly’s control side from the motor’s control circuit, reducing noise coupling.
6. Reposition the Antenna
If your garage door motor has an external antenna (sometimes a small dangling wire), try re-routing or extending it away from the Shelly and its wiring.
💡 Summary
| Problem | Likely Cause | Solution |
|---|---|---|
| 433 MHz range drop | RFI from 24V wall wart | Use linear PSU or add ferrite beads |
| Inconsistent remote response | Ground noise coupling | Isolate power supply and wiring |
| Remote only works close to motor | Noise masking RF signal | Improve antenna positioning |
🧠 Final Thoughts
Smart home integrations are fantastic, but the unintended side effects—like radio interference—can be frustrating. The good news? With a little attention to power supply quality, wiring layout, and noise suppression, your Shelly 1 and garage remote can coexist peacefully.
If you’re still stuck or want help choosing parts to reduce EMI, feel free to drop a comment below!
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