The Missing Piece: Building a DIY 4G GPS Tracker with the LILYGO SIM7600 for Traccar

Welcome back to the lab. Here's a question that doesn't get asked enough: when you count them up, how many devices are actually on your Wi-Fi? Between the Tuya plugs, Xiaomi sensors, Eufy gear, Tapo cameras, three RF bridge hubs, a small fleet of ESP32 nodes, and a couple of wall-mounted dashboard phones, this house crossed the fifty-device mark a long time ago.

Dumping all of that onto the same network as your laptop is how most smart homes start — and it's a mess. The cheap IoT gear only speaks 2.4GHz, it chatters constantly, and frankly, a ten-dollar smart plug hasn't earned the right to share airspace with the machines that matter.

Today I'll walk through how this lab splits the network: a modern router running the main 5GHz network, and two retired Huawei routers reborn as dedicated IoT access points. No new hardware was purchased in the making of this setup. Let's crack into it!

The Problem with One Big Network

Three things go wrong when everything shares one network. First, radio congestion: dozens of chatty IoT devices camping on 2.4GHz drag down the band for everyone. Second, the setup dance: half of these devices flatly refuse to pair if your phone is on 5GHz during onboarding — if you've ever toggled your phone's Wi-Fi settings for twenty minutes to pair a smart plug, you know the pain. Third, trust: cheap IoT firmware has a security track record somewhere between 'patchy' and 'yikes', and it doesn't need to see your laptop.

The textbook answer is VLANs with firewall rules between them. The pragmatic answer — the one that costs nothing and takes an afternoon — is what we're doing today.

Old Routers, New Job

Regular readers will spot the theme: just like the retired phones that became wall dashboards, the two Huawei B3 routers that used to be the main internet connection were never thrown out. Switched into bridge mode, they stop routing entirely and become plain access points — radios with an Ethernet tail.

The layout ends up clean and deliberate: the TP-Link Archer stays the one true router, handling DHCP and the 5GHz network for laptops, phones, and anything that deserves fast lanes. Each Huawei broadcasts its own dedicated 2.4GHz IoT SSID, placed at opposite ends of the house so every corner has strong 2.4GHz coverage. Two SSIDs also means the device zoo can be split between two radios instead of piling onto one — Zigbee hubs and RF bridges on one, the Wi-Fi plug-and-sensor crowd on the other.

Setting Up Bridge Mode

The recipe is nearly identical on any old router. Give it a fixed LAN address outside the main router's DHCP pool so you can always find its admin page. Disable its DHCP server — this is the step people miss, and skipping it earns you two routers fighting over who hands out addresses. Set the SSID and a strong password, pick a fixed 2.4GHz channel that doesn't overlap with the other AP (1 and 11 are the classic pairing), and cable it to the main router LAN-port to LAN-port.

From that moment, the old router is just a radio. Every IoT device joins its dedicated SSID but gets its address from the Archer, so Home Assistant, the MQTT broker, and the SonoffLAN integration all reach everything without any cross-network gymnastics.

What Lives Where

The sorting rule is simple: if it's cheap, chatty, or only speaks 2.4GHz, it goes on an IoT SSID. That covers the Tuya and Tapo gear, the Xiaomi ecosystem, the 433MHz RF bridge hubs from our RF sensors post, the ESP32 room nodes and Bluetooth proxies, and even the wall dashboard phones — they only ever talk to Home Assistant anyway.

The 5GHz main network keeps the short list: laptops, daily-driver phones, and anything that moves real data. As a bonus, the main SSID's device list is now short enough to actually read — when something new shows up there, you notice.

The Filtering Layer

Segmentation pairs beautifully with DNS filtering. As covered in the Control D post, the Archer applies filtering at the router level, which means every IoT device inherits it automatically — no client apps, no per-device setup. Fifty devices' worth of telemetry and ad-server chatter, filtered at the front door. The IoT gear never even knows.

Honest Fine Print

Full disclosure for the networking purists: bridge mode gives you separate airspace, not separate subnets. Everything still lives on one L3 network, so a truly compromised device could still see its neighbours. The bulletproof version is VLANs with inter-VLAN firewall rules, which needs kit that supports it and a weekend of tinkering — it's on the someday list.

But don't let perfect bully good. Separate SSIDs on separate radios solve the congestion problem completely, solve the 2.4GHz pairing dance completely, and give you a clean mental map of the network — using hardware that was headed for the bin. That's a lot of win for zero dollars.

The Verdict

Network segmentation sounds like enterprise business, but the budget version is one afternoon and two settings pages: bridge mode on, DHCP off. The smart home gets rock-solid 2.4GHz coverage from two dedicated radios, the main network gets its speed and its short device list back, and two old routers dodge the landfill.

Raid the closet, mate — between the old phones on the walls and the old routers in the cupboard, this lab is powered by retirement-age hardware living its best life. Cheers!

"If you've got any questions or need a hand wrangling your own setup, don't hesitate to reach out at [email protected] or connect with me via www.yazan.me. I'm always keen to help out!"