Compact 4‑channel analog‑to‑digital converter module for Pixhawk‑class autopilots and ThunderFly form‑factor carrier boards. Based on TI ADS1115 (16‑bit Σ‑Δ ADC). Dual Pixhawk JST‑GH I²C ports support in‑line daisy‑chaining.
- 4 × single‑ended inputs (AIN0…AIN3) up to VDD range (0–3.3 V)
- 16‑bit ADC (ADS1115IDGS) with programmable gain amplifier (PGA)
- I²C interface, 100/400 kHz compliant; on‑board 4.7 kΩ pull‑ups to 3.3 V
- ADDR solder-bridge for selectable I²C address (default 0x48)
- ALERT/RDY interrupt output (optional test‑point)
- Bus‑powered from +5 V; on‑board LDO to internal 3.3 V
- Input/rail protection and status LEDs (PWR, activity)
- Two JST‑GH 4‑pin I²C ports for Pixhawk; one 2×4 header for access to analog inputs and ground
- Input supply (JST‑GH VBUS): 5.4 V (Pixhawk I²C standard)
- I²C levels: 3.3 V (pull‑ups on board)
- Analog input range: 0…3.3 V (referenced to GND)
- ESD / surge: front‑end and bus clamped (5.6 V TVS on 5 V)
⚠️ Do not exceed 3.3 V on AINx relative to GND.
Pin 1: VBUS +5V
Pin 2: SCL
Pin 3: SDA
Pin 4: GND
Both ports are wired in parallel for pass‑through/daisy‑chain.
Default assembly is 0x48.
| ADDR input | 7‑bit I²C address |
|---|---|
| GND | 0x48 (default) |
| VDD (3.3 V) | 0x49 |
| SDA | 0x4A |
| SCL | 0x4B |
The board provides pads/jumper position for changing the address. See silkscreen near ADDR.
- T1 (ALERT/RDY): routes the ALERT/RDY pin to a test pad for optional host interrupt. Leave open if unused.
- JP2/JP2: board address option tie (factory) to 3.3 V.
- PWR (green): 3.3 V power rail present.
- ACT (orange): activity/diagnostic (wired to logic as per schematic option).
- Plug either JST‑GH port to a Pixhawk I2C port (5 V provided by autopilot).
- Daisy‑chain additional I²C node from the second JST‑GH if needed.
- Connect sensors to AIN0…AIN3 via J1, or wire your signals to the corresponding pads.
- (Optional) Strap ADDR and solder for a non‑default address if multiple TFI2CADC01 are present on the same I2C bus.
- PX4 support: PX4 Autopilot includes a native driver for ADS1115 (16‑bit, up to 860 SPS, 4‑channel delta‑sigma ADC with PGA, oscillator, internal VREF, comparator and I²C). See PX4 driver and TI ADS1115.
- Use cases: Pixhawk‑compatible ADC module is suitable for prototyping/attaching analog‑output sensors (e.g., temperature, humidity, gas presence, etc.).
- Configuration tips: configure PGA for expected full‑scale to maximize resolution; for single‑ended reads use MUX AIN0/1/2/3 vs GND; to minimize I²C polling enable comparator in "traditional" mode and read ALERT/RDY (if T1 is wired).
# Detect
sudo i2cdetect -y 1
# Read a register (conversion register 0x00)
sudo i2cget -y 1 0x48 0x00 wPCB follows the ThunderFly form factor for avionics modules (mounting & stacking compatible with TF carriers). Two JST‑GH side‑by‑side for easy in‑line installation inside UAV wiring harnesses.
- TFI2CADC01A - Initial revision
The TFI2CADC01 is available from ThunderFly s.r.o. For a commercial quotation, contact us at [email protected] or shop via our Lectronz or Tindie store.
We also offer application‑specific modifications on request. Typical options include alternative input scaling (dividers/shunts), connector or cable variations, pre‑strapped I²C addresses, and simple mounting adaptations. Basic changes are usually provided at no additional cost with an estimated lead time of approximately three weeks.