8x AI-ADS7828 - IoTextra Analog3
8-channel differential analog input module · 12-bit SAR ADC (ADS7828) · up to 50 kSPS · I²C only
Voltage 0–5V · Current 0–20mA / 4–20mA · HOST and Qwiic connectors · 47×56 mm · 5 VDC supply
Works with Raspberry Pi, Raspberry Pi Pico / Pico 2 (RP2040 / RP2350) and ESP32
DIN-rail mounting: A 3D-printable DIN-rail mounting tray is available — view on Printables
Part of the IoTextra series · compatible with IoTsmart and IoTbase · Open Hardware
This module 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.
Software Power: This hardware compatibility unlocks the full potential of the IoTflow platform, with native support for Tasmota as well. 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.
The IoTextra Analog3 provides eight independent differential analog input channels based on the Texas Instruments ADS7828 12-bit SAR ADC. Eight instrumentation-grade differential amplifier stages provide noise rejection before the signal reaches the ADC. Input protection diodes guard against over-voltage and ESD. Each channel is individually configurable for voltage or current measurement via solder bridge.
Key Specifications
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Supply voltage: 5 VDC (reverse polarity protected)
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ADC: ADS7828, 12-bit SAR, internal 2.5V reference
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Analog channels: 8 differential inputs (IN0–IN7)
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Sampling rate: up to 50 kSPS
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Voltage input: 0–5V (SB open)
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Current input: 0–20mA, 4–20mA (249Ω on-board shunt, SB closed)
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I²C address: configurable 0x48–0x4B via DIP switch (SW1), up to 4 modules per bus
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I²C modes: Standard (100kHz), Fast (400kHz), High-Speed (3.4MHz)
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Connectors: HOST-P12, Qwiic × 2, H1–H4 terminal blocks (3.5mm pitch)
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Indicators: analog power LED (LD1)
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Protection: Reverse polarity, TVS (SMAJ13CA), BAV99W clamp arrays, ESD on Qwiic
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Board size: 47 × 56 mm
Operation Modes
🔌 Standalone
Analog readings are available via the I²C bus, through the HOST connector or the Qwiic connectors.
🧠 Smart
An IoTsmart module is inserted vertically into the HOST connector. Analog data and the 5V module supply are provided through HOST, powered from the IoTsmart module.
🏗 Mezzanine
The module is installed into an IoTbase carrier board. Analog data and the 5V module supply are provided through HOST.
Applications
🏭
Industrial Process Monitoring
Connect 4–20mA transmitters from pressure, temperature, and flow sensors directly into all 8 channels. 50kSPS rate captures fast transients alongside slow process variables on the same I²C bus.
⚡
IIoT & Predictive Maintenance
Current clamps on motor phases and voltage dividers on power rails — all 8 channels polled at high speed to detect vibration signatures and power anomalies before failure occurs.
🌱
Smart Farming
Soil moisture, pH, and EC sensors on voltage channels; irrigation valve actuator feedback (4–20mA) on current channels — all delivered over a single I²C bus.
🏢
Building Automation (HVAC)
Temperature, humidity, CO₂, and light sensors with 0–5V or 4–20mA outputs across all 8 channels. Up to 4 modules on one I²C bus (0x48–0x4B) for zone-by-zone monitoring.
