PlainDAQ Turns the Pi Pico Into a BLE-Capable Data Acquisition Platform
With bipolar analog input, output, and ±5 volt supply.
A new carrier board for the Raspberry Pi Pico aims to turn the microcontroller platform into a general-purpose data acquisition unit. Kuncu Teknoloji announced the PlainDAQ on Crowd Supply. A Pi Pico plugs into the PlainDAQ, giving it access to Bluetooth, high-resolution analog inputs, a bipolar analog output, precision voltage reference, and a +/-5 volt supply to power sensors.
Data acquisition units (DAQs) have a wide range of uses in the test and measurement area. Often they act as data loggers or monitors for sensors that output analog signals. A microcontroller alone might seem like a more straightforward solution. Unfortunately, while they have a built-in analog-to-digital converter (ADC), on-chip noise sources hinder their performance in precision measurement applications. Plus, their input voltage range tends to be positive only and limited by the microcontroller's VCC.
PlainDAQ addresses those potential shortcomings and extends Pico's RP2040's analog capabilities. For input, there are four multiplexed channels connected to a Microchip MCP33151 ADC with 14-bit resolution, sampling at 500 kilosamples/s with bipolar (positive and negative) ranges up to 4 volts. In addition, Kuncu Teknoloji says the ADC's signal-to-noise ratio is 72 dB and can achieve an impressive 11.6 effective number of bits (ENOB)! (ENOB is often considered the figure-of-merit for an analog-to-digital system.)
For analog output, PlainDAQ features a 10-bit digital-to-analog converter (DAC). It operates with a 50 kilosample/s rate and features a ±4 volt output range. Additionally, a 2.5 volt precision reference is available.
To power sensors or other lower-power devices, PlainDAQ has a 100 mA capable power supply that can produce an output of ±5V. These wider-range analog capabilities benefit the Pico in acquisition applications since it is a 3.3 volt IO system natively.
Connectivity comes in two primary forms: serial and BLE. Wired communication comes from the Pico's USB port, which provides UART over USB. For wireless, an ESP32-mini module with AT-firmware adds Bluetooth support to PlainDAQ.
Kuncu Teknoloji says the project details will be made public. Currently, this GitHub repository has a PDF of the board's schematic. For more information and to learn when it launches, sign up for notifications on the PlainDAQ project page.
Edit: Updated information regarding Bluetooth support.