What I built#
A pocket Wi-Fi testing tool: an ESP32 wired to a TFT display and an SD card reader, powered by a small LiPo, soldered together by hand and flashed with ESP Marauder. It scans, it captures, and it runs the Wi-Fi security tests I’d otherwise only read about — against my own lab network, on its own isolated SSID.
Why#
I could have bought a finished board. Soldering it myself was the point: I wanted to understand the thing at the level of which pin does what, not just which menu option to tap. When the display didn’t come up the first time, debugging it taught me more than a working purchase ever would have.
The build#
The parts list is short and cheap:
- an ESP32 dev board
- a TFT display (SPI)
- a micro-SD reader for capture storage
- a small LiPo and a charging board
Photos of the wiring and the finished unit go here:
The fiddly part is the SPI wiring between the ESP32 and the display — shared clock and data lines, separate chip-select pins, and the display simply stays dark if any one of them is on the wrong GPIO.
Flashing ESP Marauder#
ESP Marauder (by justcallmekoko) is the firmware that turns the board into a Wi-Fi testing tool. Flashing is straightforward once the board is recognised:
esptool.py --chip esp32 --port /dev/ttyUSB0 --baud 921600 \
write_flash 0x1000 esp32_marauder.binIf the port never appears, it’s almost always the CP2102/CH340 USB-serial driver missing rather than anything wrong with the board.
Using it responsibly#
Everything I do with it happens against my own access point, on a dedicated SSID with nothing real connected to it. That matters beyond etiquette: transmitting deauthentication frames against networks you don’t own is illegal in most places, full stop. The lab AP exists so I can watch what these attacks actually look like on the receiving end — which is the part that makes defending against them make sense.
What I would do differently#
Case it sooner. It ran as a bare board on the bench for weeks, and I lost one jumper to a snagged wire before I finally printed a housing. A three-dollar enclosure would have saved the re-solder.