On the 9th day of being unemployed at home, a friend came to consult about the RFID (13.56MHZ) file management solution: the original design had a node board controlling 8 RF module boards. Although the cost of the RC522 has dropped to just a few dollars, there is no need to choose 8 RC522s for this solution (forgive my friend’s unfamiliarity with RFID 
). That’s right! It is completely feasible to use a single RC522, combined with multi-antenna switching, to achieve reading 8 tags with a single node board. What should we use for multi-antenna switching? A relay? An analog switch 4051? Or the legendary RF-specific switch? Today, we will provide a comprehensive comparison + real-world testing to help you make the right choice without pitfalls! 👇
| Feature | Relay | 74HC4051 (Analog Switch) | Dedicated RF Switch (The King) |
|---|---|---|---|
| Switching Speed | ⚠️ Very Slow (ms level) | ✅ Very Fast (ns level) | ✅✅✅ Very Fast (ns level) |
| Lifetime | ⚠️ Limited (Mechanical Wear) | ✅ Almost Unlimited | ✅✅✅ Almost Unlimited |
| Signal Loss | ✅ Very Low | ⚠️ Huge (Significant Distance Reduction) | ✅✅ Very Low (Almost No Loss in Distance) |
| Size/Noise | ⚠️ Large/Noisy | ✅ Small/Silent | ✅✅ Small/Silent |
| Cost | ✅ Relatively Low | ✅✅ Very Low | ⚠️ Relatively High |
| Recommendation Index | ⭐ (For Low-Speed Use) | ⭐⭐ (Can Adjust for Good Matching) | ⭐⭐⭐⭐⭐ |
Conclusion: How to Choose?
- Pursuing Ultimate Reading Distance + High-Speed Polling + Long-Term Stability? -> Go for the Dedicated RF Switch! (SKY13418 or HMC241SCS)
- Extremely Tight Budget, Can Accept Significant Distance Reduction, and Willing to Spend a Lot of Time Tuning Matching? -> You can try 74HC4051 (but strongly not recommended).
- Very Low Switching Frequency, Extremely High Distance Requirements, and Don’t Mind Noise and Size? -> You can consider Relay.
Remember: The Dedicated RF Switch may be a bit expensive, but the time saved in debugging, avoiding project delays, and ensuring product performance far exceeds the cost of that chip! One-time investment, long-term stability!
I hope this comprehensive guide helps everyone! Avoiding detours is the greatest success! 💪
From microcontrollers to ARMLlinx, from hardware design to PCB layout, from RFID to system solution design, from IoT to QT, rejecting routines, feel free to scan and follow me. Whether you are a beginner or an industry elite, we brainstorm and speak freely!
