Supporting Raspberry Pi^® in OEM
and Test and Measurement Applications

Popularity of Raspberry Pi

There is a lot of buzz surrounding the Raspberry Pi platform. Due to its eye-popping capabilities and low price, engineers are investigating more ways to use it in their designs.

Raspberry Pi is the 3rd best-selling general-purpose computer platform, trailing only the Microsoft^® Windows^® PC and Apple^® Macintosh^®, with over 12.5 million sold as of 2017. The secrets to its success are in price, performance, and flexibility. For $35 the Raspberry Pi 3 Model B+ offers a 64-bit quad-core ARM processor, gigabit ethernet, wireless, Bluetooth^™, 4 USB ports, micro SD slot, and HDMI output.

While originally created for the education market to teach computer science to students across the globe, it has rapidly expanded beyond the intended market into the hobbyist/maker market and increasingly into industrial/commercial markets.

Raspberry Pi Used in MCC Product Design

The power and capabilities of the Raspberry Pi is starting to be leveraged widely across industry, including by Measurement Computing where it is integrated into the design of its WebDAQ Series of data loggers. With the Raspberry Pi Compute Module 3 and a data acquisition device, MCC created the high performance WebDAQ 504 acoustic/vibration logger which acquires and logs 4 channels of 24-bit data, performs an FFT on all 4 channels, and displays the data to the user from a responsive web server. The success of the Raspberry Pi in processor intensive, professional engineering applications such as this demonstrates why it is now being considered as an OEM option for industrial designs.

Raspberry Pi in Test and Measurement

The Raspberry Pi does not have built-in Test and Measurement capabilities such as Analog-to-Digital Converters (ADCs), Digital-to-Analog Converters (DACs), or conditioned Digital Inputs and Outputs (DIO). These capabilities can, however, be expanded either through the USB port or a 40-pin header that provides GPIO pins which support both SPI and I2C. A device that connects directly to the 40-pin device and stack on the Raspberry Pi is called a HAT (Hardware Attached on Top).

Over the years, individuals have published open-source designs and small companies have sold low-cost HATs for a variety of tasks, including support for analog and digital I/O. These designs and products are adequate for the education and hobbyist/maker market but have some serious short comings for professional Test and Measurement applications. Most of these devices are provided partially assembled, without specifications or programming support.

Device validation is a vitally important step in the design process as it ensures that quality metrics are adhered to and the product performs as specified. Without this process, data derived from the product might be inaccurate and endanger results that are shared, published or used for critical design decisions. The exhaustive design and validation process under-taken by Measurement Computing and other Test and Measurement companies, makes for a significant difference between most open-source designs and low-cost Raspberry Pi HATs and commercial measurement products.

MCC Support for Raspberry Pi Applications

In order to bring professional-quality measurement products to the Raspberry Pi platform, Measurement Computing has released Universal Library for Linux^™ (UL for Linux) and a family of HATs specifically for professional Test and Measurement applications.

UL for Linux is an open-source Linux library which supports our most popular USB devices and provides a programming interface for both Python^™ and C/C++^®. This library is verified on multiple Linux distributions including Raspbian^®, the distribution most popular on Raspberry Pi computers. UL for Linux and MCC’s wide selection of USB DAQ devices, greatly expands the capabilities of the Raspberry Pi computer.

While USB is the preferred option for interfacing DAQ devices in many applications, it still requires an additional cable and box. When the form-factor and physical size of the Raspberry Pi is critical to the design, a HAT solution may be more appropriate.

MCC’s family of HATs are specifically for the Test and Measurement and OEM/ODM markets. MCC DAQ HATs come with high-quality SW libraries that support Python^™ and C/C++^® to facilitate quick and easy development. Like all MCC products, the DAQ HATS are designed in the USA, use parts sourced through proven distributors, are fully tested and come with a 30-day money back guarantee and a 1-year warranty.

Hardware Attached on Top – MCC DAQ HATs

Measurement Computing has announced two products designed for Test and Measurement applications that conform to the Raspberry Pi HAT standard. These devices provide data acquisition features in a small, stackable format with the same quality and support MCC has provided for nearly 30 years.

The MCC 118 allows users to measure 8 single-ended channels of 12-bit data at an overall throughput of 100 kS/s. Eight devices can be stacked on a single Raspberry Pi to create a 64-channel device capable of reading data at combined rate of 320 kS/s.  This product is currently orderable and shipping

The MCC 152 provides two 12-bit analog outputs along with eight 5 V or 3.3 V DIO channels enabling the creation of a full multifunction Raspberry Pi measurement and control system.  This product will be available in Q4 2018.

Learn more about the MCC DAQ HATs for Raspberry Pi at:
https://www.mccdaq.com/DAQ-HAT.aspx