4 Channel 24bit ADC with signal SPI-PI-ADC1
Ultra-Precise Data Acquisition for Professional Embedded Systems
The SPI-PI-ADC1 is a high-precision, 4-channel 24-bit Delta-Sigma ADC HAT designed to transform your Raspberry Pi into a professional-grade embedded data acquisition system. Part of the Spark Product Innovation Pi HAT family
The SPI-PI-ADC1 is a comprehensive, out-of-the-box solution engineered for immediate deployment. Designed to dock directly onto your Raspberry Pi, it removes the complexity of hardware integration with pre-written drivers and software libraries that ensure a seamless setup experience.
This board belongs to a versatile series of HATs designed for the rapid prototyping and deployment of configurable embedded systems. By simply stacking boards atop one another, you can expand your system’s analogue and digital capabilities without complex wiring.
Modular Stackability & Control:
Universal Communication: A unified SPI bus runs through the connector stack, with the Raspberry Pi acting as the master to coordinate all attached HATs via downloadable libraries.
Individual Addressing: Integrated onboard switches allow each board to be uniquely addressed, ensuring conflict-free operation.
High-Density Scaling: Supports stacking of up to 8 HATs at any one time, providing massive scalability for high-channel-count applications.
Specification Table:
| Specification | Details |
|---|---|
| Supply Voltage | 5V from Raspberry Pi or stacked PI-HAT. |
| Analogue Supply | 5V and +/- 15V generated on-board. |
| Supply Current | 100k SPS: ~120-145 mA | 10k SPS: ~95-110 mA | 1k SPS: ~75-85 mA. |
| ADC Resolution | 24-bit Delta Sigma. |
| Sampling Mode | Simultaneous with multichannel synchronisation; supports High speed, High resolution, Low power, and Low speed modes. |
| Digital Filter | 100dB attenuation after passband; Passband (-3dB) at 0.49 x SPS (up to 50kHz). |
| Analogue Filter | 6-pole configurable; Default 101Hz to 9800Hz band pass (-12dB attenuation for +/-10V input). |
| Operating Temp | -20°C to +85°C. |
| Dimensions | Conforms to standard Raspberry Pi HAT mechanical fixing points. |
| Digital Interface | SPI Mode 1; Clock up to 18MHz; 8 Pi GPIO lines for Chip Select. |
| Memory / Buffer | Onboard processor with 8Kb RAM. |
| Physical Connectors | 4 x SMA (Analogue Input), Phoenix Connector (External Power/Trigger), Pi Header (Standard/Passthrough). |
The SPI-PI-ADC1 is fully compliant with the Raspberry Pi HAT+ specification, ensuring seamless compatibility with current and future hardware. By adhering to this updated standard, we provide a consistent and reliable user experience across the entire ecosystem.
The SPI-PI-ADC1 adheres to the HAT+ mechanical standard to ensure a perfect fit for your embedded system:
Header Alignment: Fully connects to the 40-way GPIO, including dedicated ID pins for automatic board detection.
Secure Mounting: Features fixing points aligned with official Raspberry Pi mounting holes.
Header Clearance: Designed to avoid interference with the PoE headers on Raspberry Pi 4 and 5.
Thermal Compatibility: Compatible with 15mm or 16mm spacers to accommodate the Raspberry Pi Active Cooler.
- Enclosure Mounting: SMA connector diameter 6.25mm (drill to 6.5mm); features an irregular pitch—please refer to the diagram below for precise dimensions.
- Industrial Process Control: Precise monitoring of pressure transducers, load cells, and flow meters.
- Vibration & Audio Analysis: High-speed data acquisition for structural health monitoring and acoustic testing.
- Environmental Monitoring: Long-term, low-noise data logging for gas, temperature, and humidity sensors in remote locations.
- Biomedical Sciences: High-resolution sensing for laboratory instrumentation and life science research.
Edge AI & Machine Learning: Reliable real-world signal processing for advanced data-driven systems.
Test & Measurement: Compact, cost-effective precision measurement for electronic development and prototyping.
Integrate this high-precision ADC HAT into your design with ease. Access mechanical CAD, ECAD footprints, and pre-written software drivers in our Resource Library, or download the technical datasheet for full electrical and mechanical specifications.
Precision Configurable Filtering
The SPI-PI-ADC1 features a novel 6-pole analogue filter architecture designed for maximum flexibility. This system allows users to achieve Low Pass, High Pass, or Band Pass topologies simply by swapping standard resistor and capacitor values.
Signal Chain Architecture
To ensure maximum signal integrity and ADC range, the signal path is meticulously structured:
Input Attenuation: Scalable resistors to match your specific input signal levels.
Unity Gain Buffer: Ensures high input impedance and signal stability.
Multi-Feedback & Sallen-Key Filters: Successive stages for steep, precise frequency roll-off.
Differential Conversion: Converts single-ended signals to differential to utilise the full 24-bit ADC dynamic range.
Performance & Customisation
Factory Default: Ships as a 101Hz to 9800Hz band-pass filter with -12dB attenuation, optimised to convert a ±10V signal into a full-scale ADC reading.
Frequency Range: Supports custom cut-offs up to the 50kHz Nyquist limit.
Bespoke Services: For specific requirements, Spark Product Innovation offers custom filter design services (NRE) or factory-preassembled boards for bulk orders.
