Wednesday, September 25, 2019

DIY Passive PoE for Raspberry Pi Under $2

How to power a Raspberry Pi 3/4 over an Ethernet cable (up to 100 m) using passive PoE — with off-the-shelf parts costing under ~$2.

Complete passive PoE setup for Raspberry Pi

Complete setup — Raspberry Pi powered over Ethernet via passive PoE.

Warning: This uses passive PoE with T568B wiring:

  • Blue / Blue-White → + (positive) terminal of DC supply
  • Brown-White / Brown → − (negative) terminal of DC supply

If you don't know what passive PoE is, do not proceed — buy a proper PoE HAT instead.

Parts needed

1. PoE injector cable (~$0.80)

PoE injector cable

PoE injector cable — splits power and data onto the Ethernet cable.

PoE injector cable — connector detail

Connector detail of the PoE injector cable.

PoE injector cable — wiring detail

Wiring detail of the PoE injector cable.

2. DC-DC buck converter (~$0.50) — look for Hesai brand on AliExpress, 12–24 V input, 5 V / 3 A output.

DC-DC buck converter module

DC-DC buck converter — 12–24 V input to 5 V / 3 A output.

Assembly

3. Solder jumper wires — Cut female-to-female jumper wire into 4 pieces and solder to the buck converter as shown:

Soldering jumper wires to buck converter

Jumper wires soldered to the DC-DC buck converter.

Wiring diagram for buck converter connections

Wiring diagram — connecting the buck converter to the PoE splitter.

4. Heatshrink and connect — Cover the DC-DC converter in a heatshrink sleeve and connect to the Raspberry Pi:

Buck converter in heatshrink connected to Raspberry Pi

DC-DC converter in heatshrink sleeve, connected to the Raspberry Pi.

5. Final setup — Feed 12 V DC and network into the PoE injector, then run a CAT-5 cable (up to 100 m) between the injector and the Raspberry Pi:

Complete passive PoE setup diagram

Complete setup — 12 V DC + network through PoE injector to Raspberry Pi over CAT-5.

Saturday, August 24, 2019

Flash OpenWrt on the A5-V11 Pocket Router

Step-by-step guide to replace the stock Qualcomm firmware on an A5-V11 pocket router (~$5) with OpenWrt, giving you a fully hackable Linux device.

What you need

  • A5-V11 pocket router (Qualcomm variant)
  • FAT-formatted USB flash drive
  • PC with Ethernet port
  • Ethernet cable
  • 5 V USB power source

Step 1 — Prepare the USB drive

Download and unzip a5-v11-openwrt.zip onto a FAT-formatted USB flash drive.

Important: Do not just copy the .zip file — extract it so the folder containing openwrt-factory.bin, the bootloader, and update scripts sits at the root of the drive.

Step 2 — Connect the hardware

Wire up the A5-V11, USB drive, PC, and power as shown:

A5-V11 hardware setup: router, USB drive, Ethernet cable, and power

Hardware setup: A5-V11 router with USB flash drive, Ethernet to PC, and 5 V power.

Step 3 — Power on and wait

Apply 5 V power. The RED LED stays on for a few seconds, then the BLUE LED starts blinking (takes about 1 minute from power-on). Your PC should receive an IP in the 192.168.100.x range from the router's DHCP server.

Step 4 — Verify Qualcomm firmware

Open the router's web UI and confirm it shows the Qualcomm interface:

A5-V11 Qualcomm OEM web UI

Qualcomm OEM web interface — confirm your router shows this page before continuing.

A5-V11 Qualcomm firmware details

Qualcomm firmware detail page.

Stop here if your router's web page looks different from the screenshots above. You may have a Chinese firmware variant — follow this other guide instead.

Step 5 — Telnet in and flash

Open a telnet session to the router using PuTTY or a terminal:

Telnet connection to A5-V11

Telnet session to the A5-V11 router.

Run the firmware flash commands as shown:

Flash commands running on A5-V11

Running the OpenWrt flash commands via telnet.

Step 6 — Reboot into OpenWrt

After reboot, wait about a minute. OpenWrt will boot and your PC will get an IP in the 192.168.1.x range. Open a browser and you should see the OpenWrt LuCI interface:

OpenWrt LuCI login page

OpenWrt LuCI login screen — use the default root user with no password.

OpenWrt dashboard after login

OpenWrt dashboard. From here you can flash your own custom OpenWrt variant via System → Backup/Flash Firmware.

Next step: You can now overwrite this base OpenWrt image with your own custom build via the System → Backup/Flash Firmware menu.

Thursday, January 03, 2019

Wi-Fi LED Fairy Light Controller with ESP8266

A DIY Wi-Fi-controlled 5 V switcher for USB LED fairy lights, built around an ESP-12F module running Tasmota firmware. Powered by a battery bank, it lets you toggle garden lights remotely from your phone — no 230 V wiring outdoors and no freezing walks to the power outlet.

LED fairy lights in the garden
LED fairy lights switched on at night

The lights

"USB Fairy Lights" or "USB String Lights" — 10 m / 100 LEDs, available from China for under ~$3. They are 5 V USB-powered and weather-proof (except the USB connector).

USB LED string light product photo
Close-up of the LED string circuit

The 100-LED circuit with 5.1 Ohm series resistor — consumes ~1.8 W at 5 V.

Close-up of a single LED

Close-up of a single LED — brightness difference between first and last LED is barely noticeable from a distance.

The ESP-12F 5 V switcher

An ESP-12F module with a MOSFET switches the USB 5 V supply to the LED string. Running Tasmota firmware, it connects to your Wi-Fi network and can be controlled from a phone or any MQTT/HTTP client.

ESP-12F switcher board — front
ESP-12F switcher board — rear
Complete setup — battery bank, ESP switcher, and LED string

Complete setup — battery bank, ESP-12F switcher, and LED fairy lights.

With Tasmota's default configuration (no deep sleep), the battery bank needs recharging every few days. A larger battery and ESP8266 deep sleep could extend runtime to weeks.

Assembly

Before starting, ensure the ESP-12F module is pre-programmed with Tasmota (or any OTA-capable firmware). See ESP-12F programming guide for first-time flashing.

Items needed:

Parts laid out for the build

Step 1:

Assembly step 1

Step 2:

Assembly step 2

Step 3:

Assembly step 3

Step 4:

Assembly step 4

Step 5:

Assembly step 5

Step 6:

Assembly step 6

Step 7:

Assembly step 7

Step 8:

Assembly step 8

Step 9:

Assembly step 9

Final assembly:

Completed switcher assembly
Switcher connected to battery bank and LED string

Completed setup — ESP-12F switcher between battery bank and LED fairy lights.

Tuesday, January 01, 2019

$20 Pocket Router as Domoticz Smart Home Gateway

A custom OpenWrt firmware (autom8box) that packs router + Domoticz server + MQTT broker into an all-in-one home automation gateway running on a ~$20 off-the-shelf GL-MT300N-V2 pocket router.

Domoticz home automation gateway setup diagram

System overview: GL-MT300N-V2 running autom8box firmware as Wi-Fi AP, MQTT broker, and Domoticz server.

The problem

Wi-Fi based home automation products are cheaper than Zigbee or Z-Wave, but they typically require internet connectivity. Letting cloud servers control your home devices is not ideal — internet should be optional, not mandatory.

Thanks to the open-source community (Tasmota, ESPurna, etc.) for helping jailbreak devices like Sonoff, Blitzwolf, and Teckin. But jailbreaking solves only part of the problem — you still need a home automation gateway: Wi-Fi access point + MQTT broker + automation server (Domoticz, OpenHAB, etc.).

What autom8box provides

  • Wi-Fi access point — dedicated network for your IoT devices
  • DHCP and DNS server — automatic network configuration
  • MQTT broker (Mosquitto) — message bus for IoT devices
  • Domoticz — home automation dashboard and rules engine
GL-MT300N-V2 pocket router

GL-MT300N-V2 (~$20) — compact pocket router running the autom8box firmware.

Limitations: Limited Wi-Fi range and a reduced set of Domoticz plugins due to the 16 MB flash limit. But it's a good starting point for low-budget home automation.

Flashing steps

Step 1Download autom8box-mt300nv2.bin.

Step 2 — Power on the GL-MT300N-V2 and wait for its SSID to appear (shown as GL-MT300N-V2-xxx).

GL-MT300N-V2 SSID visible in Wi-Fi list

OEM SSID appearing in the Wi-Fi list.

Step 3 — Connect to the SSID. When prompted for a password, enter goodlife (printed on the device's back sticker).

Wi-Fi password prompt

Enter the default Wi-Fi password.

Step 4 — Once connected, you should see the confirmation message:

Wi-Fi connected confirmation

Successfully connected to the router.

Step 5 — Open a browser and navigate to:
http://192.168.8.1/cgi-bin/luci/admin/system/flashops

LuCI login page

LuCI login — leave the password box empty and click "Login".

Step 6 — In the firmware update section, uncheck "Keep settings", choose autom8box-mt300nv2.bin, then click "Flash Image".

Firmware upload page

Firmware upload — uncheck "Keep settings" and select the autom8box binary.

File selected for flashing

File selected — ready to flash.

Step 7 — Click "Proceed" to confirm:

Flash confirmation dialog

Confirm flashing — click "Proceed".

Step 8 — Wait about 2 minutes for the flash to complete:

Flashing in progress

Firmware flashing in progress — wait for the device to reboot.

Step 9 — After reboot, a new SSID autom8box will appear. Connect with password goodlife.

autom8box SSID in Wi-Fi list

The new autom8box SSID is now visible.

Step 10 — Open http://192.168.8.1:8080 in your browser — Domoticz is ready:

Domoticz dashboard running on autom8box

Domoticz home automation dashboard — running entirely on the pocket router.

Post-setup security

SSH credentials: user root, password goodlife

Change root password:

passwd root

Change Wi-Fi password:

uci set wireless.default_radio0.key=my-new-password
uci commit wireless
wifi

Change SSID:

uci set wireless.default_radio0.ssid=my-new-ssid
uci commit wireless
wifi

Important: autom8box does not auto-save the Domoticz database. After configuring your devices, SSH in and run reboot — during reboot the database is saved from RAM to the persistent partition. A hard power cut without rebooting may lose your configuration.

SOURCE CODE

github.com/hackboxguy/lede-a5v11 — build instructions and sources

autom8box-mt300nv2.bin — pre-built firmware image