IoTextra Combo
2 differential analog inputs (16-bit ADS1115) + 2 SPDT relays · 10A · 250VAC / 30VDC · GPIO and/or I²C
Voltage: ±0.5V · ±5V · ±10V · 0–0.5V · 0–5V · 0–10V
Current: 0–20mA · 4–20mA · ±20mA · 0–40mA
HOST and Qwiic connectors · 47×56 mm · 5 VDC supply · compatible with IoTsmart and IoTbase · Open Hardware
The IoTextra Combo module is a versatile solution that combines two distinct systems on a single board: high-precision analog data acquisition and power switching via mechanical relays. It is a member of the IoTextra series, which serves as a fundamental building block of our ecosystem and embodies the Make Things Happy Philosophy. It is engineered to bridge the gap between rapid prototyping and industrial-grade reliability.
Hardware Synergy: The module is compatible with both IoTsmart and IoTbase series.
Note: Usage with IoTbase or horizontal-mounted IoTsmart versions (V-HOST connector) requires a Height Extender or a dedicated riser adapter.
Software Power: This hardware compatibility unlocks the full potential of the IoTflow platform. It enables you to:
- Create custom Node-RED nodes effortlessly.
- Integrate via MQTT with third-party global platforms like Blynk.
- Scale your project from a single node to a complex industrial network.
Key Specifications
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Relays: 2× SPDT (1 Form C), 10A at 250VAC / 30VDC
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ADC: 16-bit ADS1115 Delta-Sigma (Texas Instruments)
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Analog inputs: 2 differential channels, voltage or current (via solder bridge)
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Voltage ranges: 0–0.5V, 0–5V, 0–10V, ±0.5V, ±5V, ±10V
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Current ranges: 0–20mA, 4–20mA, ±20mA, 0–40mA
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Measurement speed: up to 860 samples per second
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Relay control: AP0–AP1 (RL1–RL2) via HOST connector, and/or I²C via TCA9534 (or compatible) expander
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I²C addressing: DIP-switch selectable, up to 16 modules per bus
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Connectors: HOST (12-pin), Qwiic × 2
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Protection: Reverse polarity, ESD (TVS on Qwiic)
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Size: 47 × 56 mm, with mounting holes for base-module or Raspberry Pi installation
Precision: Lite / STD
The module is available in two precision grades, differing only in the tolerance and stability of the passive components in the analog section — both use the same REF3425 voltage reference and TLV333 zero-drift op-amps:
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STD: 0.1% low-T.C. resistors, high-stability filter capacitors
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Lite: 1% industrial resistors, industrial low-ESR filter capacitors
Operation Modes
🔌 Standalone
Access analog and relay signals via the HOST connector or Qwiic I²C connectors from any host controller.
🧠 Smart
An IoTsmart module is plugged into the HOST connector. Communication and the 5V module supply are provided through HOST, powered from the IoTsmart module.
🏗 Mezzanine
The module is installed into an IoTbase carrier board. Communication is through the HOST connector.
Applications
🏭
Industrial Telemetry & PLC Integration
Collects data from 4-20mA and 0-10V sensors in high-EMI environments, while the onboard relays switch small industrial loads directly — a compact, space-efficient alternative to separate analog and relay modules.
🌱
Smart Agriculture
Monitors soil moisture, pH, and conductivity (EC) sensors while simultaneously controlling irrigation pumps via the onboard relays — sensing and actuation on a single board.
🤖
Robotics & Lab Automation
Combines signal measurement and load switching in a single test bench — long-term reading stability suits calibration rigs and automated test equipment.
🏠
Smart Home
Reads sensor feedback (temperature, light level, moisture) on the analog channels while the onboard relays switch lighting, pumps, or small actuators — sensing and control combined on one board.
