# CAR-KEY-KILLER Dual-band RF jamming system for automotive key fob frequencies. ESP32-S3 + dual CC1101 + external amplifiers + OLED display + web interface. --- ## WHAT IT DOES Every car key fob on the market operates on one of two narrow sub-GHz bands. This device sweeps both bands simultaneously with continuous FM noise, leaving zero gaps between hops and zero time for a fob transmission to get through. 300 - 320 MHz North American band Honda/Acura 303.825 MHz Chamberlain/LiftMaster 310.0 MHz Toyota/Lexus/Scion 314.98 MHz Ford/GM/Chrysler/Dodge/Jeep 315.0 MHz Linear Delta-3 / LiftMaster 318.0 MHz 390 - 436 MHz European and global band Chamberlain/LiftMaster 390.0 MHz Holtek-based remotes 418.0 MHz Somfy RTS / SMC 5326 433.42 MHz BMW/VW/Audi/Mercedes/Hyundai/Kia 433.92 MHz Asian/Euro fobs 434.42 MHz A fob button press generates a 200-500ms transmission window. Radio 1 completes a full sweep of 300-320 MHz every 75ms. Radio 2 completes a full sweep of 390-436 MHz every 180ms. Every target frequency gets hit multiple times per fob press. The car never receives a clean signal. --- ## HARDWARE [BILL OF MATERIALS] 1 x ESP32-S3 DevKitC-1 (16MB Flash, 8MB PSRAM) 2 x CC1101 transceiver module (Texas Instruments) 2 x RF power amplifier module (+20 dB gain, 433/315 MHz rated) 1 x 0.96 inch SSD1306 OLED display (128x64, I2C) 1 x Rotary encoder (KY-040 or equivalent, with detents) 2 x Quarter-wave antenna 315 MHz: 23.8 cm wire or tuned whip 433 MHz: 17.3 cm wire or tuned whip 1 x USB power supply, 5V 2A minimum --- ## PIN MAPPING [SPI BUS - shared between both CC1101 modules] GPIO 11 MOSI GPIO 12 SCK GPIO 13 MISO [CC1101 NUMBER 1 - 300-320 MHz sweep] GPIO 7 CS (chip select, dedicated) GPIO 4 GDO0 (LEDC PWM noise output) 3V3 VCC GND GND [CC1101 NUMBER 2 - 390-436 MHz sweep] GPIO 8 CS (chip select, dedicated) GPIO 5 GDO0 (LEDC PWM noise output) 3V3 VCC GND GND [RF AMPLIFIERS] Inline between each CC1101 ANT pin and its antenna. VCC from 3V3 or 5V depending on amplifier module spec. +20 dB gain each. Default effective output: 10 + 20 = 30 dBm. [OLED DISPLAY - 0.96 inch SSD1306] GPIO 17 SDA GPIO 18 SCL 3V3 VCC GND GND [ROTARY ENCODER] GPIO 14 CLK GPIO 21 DT GND GND (internal pull-ups active, no external resistors needed) --- ## JAMMING PARAMETERS [RF CONFIGURATION] Modulation FM noise (direct async TX via GDO0 LEDC PWM) Frequency deviation 380 kHz (CC1101 hardware maximum) Noise bandwidth ~1010 kHz per hop (Carson rule: 2 x (380 + 125)) Bitrate 250 kbps RX bandwidth 812 kHz (maximum) TX power -30 / -20 / -15 / -10 / 0 / 5 / 7 / 10 dBm (8 steps) Default TX power 10 dBm Amplifier gain +20 dB (configurable in web UI) Effective output 30 dBm / ~1 Watt (with amplifiers, at 10 dBm TX) [SWEEP CONFIGURATION - defaults] Radio 1 center 310.0 MHz Radio 1 span 20.0 MHz (300 - 320 MHz) Radio 1 steps 25 (0.83 MHz spacing, within 1 MHz hop width) Radio 1 cycle time 75 ms (25 steps x 3ms dwell) Radio 2 center 413.0 MHz Radio 2 span 46.0 MHz (390 - 436 MHz) Radio 2 steps 60 (0.77 MHz spacing, within 1 MHz hop width) Radio 2 cycle time 180 ms (60 steps x 3ms dwell) Dwell per hop 3 ms Gap between hops none (hop bandwidth > step spacing) All sweep parameters are adjustable live from the web interface and persist across reboots via NVS (ESP32 non-volatile storage). --- ## OLED DISPLAY The 0.96 inch OLED runs three cycling pages. The yellow hardware zone at the top of these displays is used as the page header on every page. Pages advance automatically every 8 seconds or manually with the rotary encoder. Three dot indicators in the header show the current page. [PAGE 0 - STATUS] (default) Header: inverted bar reading JAMMING ACTIVE when running, STANDBY when not Row 1: ANT1 current frequency in MHz with animated radio-wave arcs Row 2: ANT2 current frequency in MHz with animated radio-wave arcs Row 3: TX power breakdown: radio dBm + amp gain = effective dBm Row 4: FULL DUAL-BAND TX badge when both radios active, else temp and heap Row 5: uptime since boot [PAGE 1 - FREQ AND HOPS] Header: FREQ AND HOPS R1 current frequency and total hop count since boot R2 current frequency and total hop count since boot Estimated total hops per second [PAGE 2 - SYSTEM HEALTH] Header: SYS HEALTH Temperature (ESP32-S3 internal sensor, Celsius) Heap: current free KB and minimum recorded KB Uptime: hours, minutes, seconds Effective power: dBm and milliwatts WiFi clients connected to the AP [BOOT SEQUENCE] The display shows synchronous status messages during boot: SPI init, WiFi AP start, Radio 1 init, Radio 2 init, final state. [NOTIFICATIONS] Full-screen inverted overlay appears for 2.5 seconds on: - Jamming started or stopped - TX power level changed - Radio reinitialization triggered by watchdog - Signal detected during capture - Capture/Replay started or stopped --- ## CAPTURE AND REPLAY The system includes a fully autonomous signal capture mode for recording and replaying raw fob signals directly into the ESP32 RAM. [FEATURES] Universal Capture: Record up to 4 seconds of raw demodulated RF data at 100 kHz directly from the CC1101 GDO0 pin. Software Squelch: An advanced ISR-level edge detector filters out thermal noise and automatically alerts you ("SIGNAL CAUGHT") the moment a legitimate encoded transmission is intercepted. Modulation Agnostic: Select between OOK/ASK (used by 90% of legacy remotes) or 2-FSK via the Web UI before capturing. Bitrate Estimation: The web interface automatically counts symbol transitions in the buffer to approximate the baud rate and duty cycle of the captured fob. Live Waveform: The UI renders a downsampled view of the captured signal payload directly in the browser. Infinite Loop Replay: Replays the 50 KB bit-packed buffer into direct async TX mode endlessly until manually stopped. --- ## WEB INTERFACE Connect to the WiFi access point, then open the control panel in a browser. SSID: killer Password: password IP: 192.168.4.1 mDNS: http://killer.local OTA port: 3232 [CONTROLS] Start / Stop jamming toggle TX power selector (8 levels: -30 dBm to 10 dBm) Amplifier gain input (dB, affects displayed effective power only) Sweep dwell time (ms per hop) Radio 1 steps and span (MHz) Radio 2 steps and span (MHz) All settings persist to NVS on save [VISUALIZATIONS] Two canvas sweep displays, one per radio band. Each shows the sweep range with named frequency markers: 315 MHz band: Honda, Toyota, LiftMaster, Ford/GM markers 433 MHz band: LiftMaster 390, Holtek 418, Somfy, BMW/VW/Audi markers Current hop position shown with a heat trail fading over recent positions. Canvas height 90px, updates every 1 second with telemetry. Two sparkline charts showing 2-minute rolling history: Temperature (Celsius) Free heap (KB) [METRICS GRID - 12 stats updated every 1 second] Effective TX power (dBm) Radio 1 status Radio 2 status ESP32 temperature (color coded: white normal, yellow warn, red critical) Free heap KB (color coded) Minimum heap KB recorded Hop count Radio 1 (total since boot) Hop count Radio 2 (total since boot) Combined hops per second WiFi clients on AP Uptime 24-hour mission progress bar in the header [LOGS] Timestamped log ring buffer, last 50 entries. Format: [HH:MM:SS] message Refreshes every 5 seconds. Covers boot events, radio status, settings changes, watchdog events, temperature warnings, low heap warnings, and heartbeat lines. --- ## RELIABILITY FEATURES (24-HOUR OPERATION) The system is designed to run unattended at full power indefinitely. Watchdog timer Detects radio lock-up, reinitializes both CC1101s Low heap protection Reboots cleanly if free heap drops below 15 KB Temperature alarm Logs warning if internal temp exceeds 75 C Temperature alarm rate limit Warning logged at most once per minute Radio status flags Tracks per-radio TX state, triggers reinit on fail NVS persistence All settings survive power cycles and reboots ArduinoOTA Firmware can be updated over WiFi without USB Heap tracking Records minimum heap ever seen since boot Hop counting Per-radio total hop counts logged and displayed --- ## BUILD AND FLASH [REQUIREMENTS] PlatformIO Core or PlatformIO IDE (VS Code extension) USB cable to ESP32-S3 DevKitC-1 [COMMANDS] pio run --target upload flash firmware pio device monitor serial monitor at 115200 baud pio run --target clean clean build artifacts [BUILD NOTES] The project sets build_dir to /Users/drjones/.pio_builds/car_fob_killer to keep build artifacts outside of iCloud Drive. This prevents a known SCons sconsign database eviction bug when the project folder is under com~apple~CloudDocs. If you move the project, update build_dir in platformio.ini accordingly. [LIBRARIES] RadioLib patched fork (CC1101 direct async TX support) U8g2 OLED display driver Preferences NVS storage wrapper ArduinoOTA over-the-air firmware updates Wire I2C bus for OLED WebServer HTTP server for control panel WiFi SoftAP mode ESPmDNS killer.local hostname --- ## SOFTWARE ARCHITECTURE [FILE STRUCTURE] src/main.cpp all firmware logic include/config.h pin definitions, frequency and RF parameters, defaults platformio.ini build config, library dependencies, build_dir override [KEY FUNCTIONS IN MAIN.CPP] startJamming() initializes both CC1101s, sets power, starts async TX tickSweep() advances one radio by one hop step oledTick() OLED update loop, handles pages and notifications oledDrawStatus() page 0 renderer oledDrawFreq() page 1 renderer oledDrawHealth() page 2 renderer oledNotify() queues a full-screen notification oledBootMsg() synchronous boot status message encISR() rotary encoder interrupt service routine handleToggle() HTTP handler: start/stop jamming handleSettings() HTTP handler: update sweep and power parameters handleTelemetry() HTTP handler: JSON status for web UI polling handleLogs() HTTP handler: timestamped log ring buffer handleRoot() HTTP handler: serves embedded web UI HTML logLine() timestamped log entry to ring buffer and Serial loop() sweeps both radios, runs OLED, runs OTA, watchdog [SWEEP LOOP TIMING] Both radios are swept independently in the same loop() pass. tickSweep() is a no-op if less than sweepDwellMs have elapsed. There are no blocking delays in the main loop. OLED and web server run interleaved with no impact on sweep timing. --- ## CONFIGURATION REFERENCE Key defines in include/config.h: CC1101_1_CS GPIO 7 chip select, Radio 1 CC1101_1_GDO0 GPIO 4 data pin, Radio 1 CC1101_2_CS GPIO 8 chip select, Radio 2 CC1101_2_GDO0 GPIO 5 data pin, Radio 2 SPI_MOSI_PIN GPIO 11 SPI_SCK_PIN GPIO 12 SPI_MISO_PIN GPIO 13 OLED_SDA_PIN GPIO 17 OLED_SCL_PIN GPIO 18 ENC_CLK_PIN GPIO 14 ENC_DT_PIN GPIO 21 WIFI_AP_SSID killer WIFI_AP_PASS password WEB_PORT 80 JAM_BITRATE_KBPS 250.0 JAM_FREQ_DEV_KHZ 380.0 (CC1101 maximum) JAM_RX_BW_KHZ 812.0 (CC1101 maximum) SWEEP_DWELL_MS 3 SWEEP_1_CENTER_MHZ 310.0 SWEEP_1_SPAN_MHZ 20.0 SWEEP_1_STEPS 25 SWEEP_2_CENTER_MHZ 413.0 SWEEP_2_SPAN_MHZ 46.0 SWEEP_2_STEPS 60 DEFAULT_JAM_POWER_IDX 7 (index into CC1101 power table, 7 = 10 dBm) DEFAULT_AMP_GAIN_DB 20 JAMMING_ENABLED true (start transmitting immediately on boot) --- ## TROUBLESHOOTING [Radios not initializing] Check SPI wiring: MOSI=11, SCK=12, MISO=13. Verify CS pins: GPIO7 for Radio1, GPIO8 for Radio2. Both CC1101s must be powered from 3V3, not 5V. Check serial output at 115200 baud for specific RadioLib error codes. [OLED blank after flash] Verify wiring: SDA=GPIO17, SCL=GPIO18, VCC=3V3. Firmware probes both 0x3C and 0x3D. Check serial for OLED found message. Most 0.96 inch SSD1306 modules run on 3V3 VCC. [Rotary encoder not responding] Verify CLK=GPIO14, DT=GPIO21, and encoder GND connected. No pull-up resistors needed, internal pull-ups are enabled in firmware. Turn slowly - one detent at a time changes page. [Web UI not loading] Connect to WiFi SSID "killer", password "password". Navigate to http://192.168.4.1 or http://killer.local. Only one device can use the AP at a time. [OTA update failing] Device must be powered on and jamming (or standby). Use PlatformIO OTA upload target, hostname "killer", port 3232. [Build fails with sconsign error] iCloud Drive evicts SCons temp files. Ensure build_dir in platformio.ini points to a non-iCloud path. Current setting: /Users/drjones/.pio_builds/car_fob_killer --- ## LEGAL Operation of intentional radio frequency jammers is illegal in most jurisdictions without specific government authorization. This includes the United States (FCC 47 CFR 333), European Union, Canada, Australia, and the United Kingdom. This project exists for authorized RF security research, shielded lab testing, and educational study of sub-GHz radio systems. The developer accepts no responsibility for use outside of those contexts. --- ## REPOSITORY https://gitea.thetempleofdoom.com/drjones/car-key-killer.git