FH4R2-class resources, 2 MB PSRAM, native USB.
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CONTROLLERESP32-S3 / 4 MB DISPLAYST7796U / 480 × 320 RADIOExternal ExpressLRS / CRSF BOUNDARYNo approved battery pack
reference hardware
What you need to build SourceTX.
This page lists the parts and connections used by the reference transmitter. The battery, charger, enclosure, and radio module are still your choice.
Landscape touch interface.
400 kbaud signal path on GPIO 42.
Battery, charger, enclosure, and RF module remain builder-selected.
parts checklist
What you need
Start with the reference interfaces below. Use the installation guide and electrical boundaries before powering a connected vehicle or radio module.
01 / MCUCORE
ESP32-S3 controller board
Use an ESP32-S3-FH4R2 configuration or a SuperMini-class carrier that exposes the same resources and pins.
- 4 MiB quad-I/O flash
- 2 MiB PSRAM
- Native USB available
- 3.3 V GPIO logic
02 / DISPLAYUI
ST7796U TFT + FT6x36 touch
A 480 × 320 ST7796U panel in landscape rotation with an FT6x36-family capacitive touch controller.
- Touch I²C address 0x38
- Shared I²C bus with INA219
- SPI display interface
- Backlight control on GPIO 3
03 / CONTROLSINPUT
Two analog controls + five buttons
Use two potentiometers with ADC-safe endpoints for steering and throttle, plus five active-low navigation buttons wired to ground.
- Steering wiper: GPIO 6
- Throttle wiper: GPIO 5
- Navigation: GPIO 35–39
- Common logic ground required
04 / MONITORINGPOWER
INA219 battery monitor
The transmitter battery monitor connects over I²C and uses the sensor’s normal default address. It measures; it does not manage or charge the battery.
- I²C SDA: GPIO 8
- I²C SCL: GPIO 9
- INA219 default address
- Warning-only battery policy
05 / RADIOCRSF
ExpressLRS / CRSF module path
Use an external radio module, a suitable antenna, a compatible receiver, and a safe test load. The firmware provides the signal path, not RF power.
- CRSF signal: GPIO 42
- Single-wire UART
- 400 kbaud
- Connect the approved antenna before RF power
06 / OPTIONALFEEDBACK
Voice or haptic add-ons
Optional outputs can drive a properly powered feedback stage. A DFPlayer Mini-compatible voice module is supported when configured with its own microSD and speaker/amplifier path.
- Never power loads from GPIO
- Use suitable drivers and protection
- Follow module voltage guidance
- Keep UART assignments unique
default wiring
Reference pin map
These are the default tested assignments. Compatible wiring revisions can use the browser or companion configuration tools, but a changed profile is a new untested wiring revision.
| Function | Connection | Notes |
|---|---|---|
| Steering potentiometer | GPIO 6 | 12-bit ADC input |
| Throttle potentiometer | GPIO 5 | 12-bit ADC input |
| CRSF signal | GPIO 42 | Single-wire UART / 400 kbaud |
| Navigation buttons | GPIO 35–39 | Active-low, internal pull-ups |
| I²C bus | GPIO 8 / 9 | SDA / SCL, touch + INA219 |
| Display control | GPIO 2, 3, 7, 10, 13, 14 | Clock, backlight, MOSI, reset, D/C, CS |
Important:SourceTX does not currently certify a finished transmitter, battery, charger, protection circuit, enclosure, or RF-module combination. Never connect battery voltage to an ADC or GPIO, and never power a radio, motor, haptic motor, buzzer, or backlight directly from an ESP32 pin.Open public installation resources →