In this chapter I show you the main features of Raspberry Pi 4B, Qwiic pHAT module and AS7263 sensor. 

Raspberry Pi 4B

This product’s key features include a high-performance 64-bit quad-core processor, dual-display support at resolutions up to 4K via a pair of micro-HDMI ports, hardware video decode at up to 4Kp60, up to 4GB of RAM, dual-band 2.4/5.0 GHz wireless LAN, Bluetooth 5.0, Gigabit Ethernet, USB 3.0, and PoE capability (via a separate PoE HAT add-on). The dual-band wireless LAN and Bluetooth have modular compliance certification, allowing the board to be designed into end products with significantly reduced compliance testing, improving both cost and time to market.

• Broadcom BCM2711, Quad core Cortex-A72 (ARM v8) 64-bit SoC @ 1.8GHz
• 1GB, 2GB, 4GB or 8GB LPDDR4-3200 SDRAM (depending on model)
• 2.4 GHz and 5.0 GHz IEEE 802.11ac wireless, Bluetooth 5.0, BLE
• Gigabit Ethernet
• 2 USB 3.0 ports; 2 USB 2.0 ports.
• Raspberry Pi standard 40 pin GPIO header (fully backwards compatible with previous boards)
• 2 × micro-HDMI ports (up to 4kp60 supported)
• 2-lane MIPI DSI display port
• 2-lane MIPI CSI camera port
• 4-pole stereo audio and composite video port
• H.265 (4kp60 decode), H264 (1080p60 decode, 1080p30 encode)
• OpenGL ES 3.1, Vulkan 1.0
• Micro-SD card slot for loading operating system and data storage
• 5V DC via USB-C connector (minimum 3A*)
• 5V DC via GPIO header (minimum 3A*)
• Power over Ethernet (PoE) enabled (requires separate PoE HAT)
• Operating temperature: 0 – 50 degrees C ambient

AS7263 NIR Sensor

The AS7263 Near Infrared (NIR) Spectral Sensor brings spectroscopy and makes it easier to measure and characterize different materials absorb and reflect different wavelengths of light. The Sparfun AS7263 Breakout has the ability to communicate by both an I2C interface and serial interface using AT commands. Hookup is easy, thanks to the Qwiic connectors attached to the board.

The AS7263 spectrometer detects wavelengths in the visible range at 610, 680, 730, 760, 810 and 860nm of light, each with 20nm of full-width half-max detection. The board also has multiple ways for you to illuminate objects that you will try to measure for a more accurate spectroscopy reading. There is an onboard LED that has been picked out specifically for this task, as well as two pins to solder your own LED into. The I2C address of the AS7263 is 0x49 and is hardware defined.

• 6 near-IR channels: 610nm, 680nm, 730nm, 760nm, 810nm and 860nm, each with 20nm FWHM
• NIR filter set realized by silicon interference filters
• 16-bit ADC with digital access
• Programmable LED drivers
• 2.7V to 3.6V with I2C interface

Below you can see the spectral responsivity of this sensor.

SparkFun Qwiic pHAT v2.0 

The SparkFun Qwiic pHAT connects the I2C bus (GND, 3.3V, SDA, and SCL) on your Raspberry Pi to an array of Qwiic connectors on the HAT. Since the Qwiic system allows for daisy-chaining boards with different addresses, you can stack as many sensors as you’d like. The Qwiic pHAT V2.0 has four Qwiic connect ports (two on its side and two vertical), all on the same I2C bus. It also add a simple 5V screw terminal to power boards that may need more than 3.3V and a general-purpose button. This pHAT is compatible with any Raspberry Pi that utilizes the standard 2x20 GPIO header.

• 4x Qwiic Connection Ports
• 1x 5V Tolerant Screw Terminal
• 1x General Purpose Button
• HAT-compatible 40-pin Female Header