Bench Talk

 In days past, I traveled to Switzerland many times a year. Switzerland is a country of great natural beauty. I enjoyed skiing its slopes and learning how to curl—the sport of pushing a granite stone of about 18.6kg on the ice.

One thing I always had to do before coming back home to my wife and family was to get some Swiss chocolate. The Swiss are known for eating more chocolate than any other nation, about 11kg per year. While Toblerone was a popular favorite, my personal preference was the Lindt milk chocolate. I am sure that only a small percentage of what was purchased ever made it was back home to my wife and kids (Figure 1).

Figure 1: Switzerland is responsible for Toblerone and Lindt chocolate. Yummy! (Source: Toblerone and Lindt)

Besides great milk chocolate, the Swiss also invented something that every engineer loves—the Swiss Army knife (Figure 2). Who wants a knife that is simply limited to cutting? Boring!

Figure 2: The Swiss Army knife provides several tools in one convenient package. (Source: Getty Images)

What every engineer wants is the ultimate do-everything multi-tool. The versatile Swiss Army knife offers all sorts of features including large blades, small blades, nail files, saws, fish scalers, scissors, wire strippers, Philips and flathead screwdrivers, and of course all manner of can openers. You’ll never find yourself unable to open and enjoy your favorite refreshment no matter where you are or what you are doing. For example, you can dress and clean the salmon you just caught while you open and enjoy a cold beverage without leaving the lake because you have all the tools you need in one convenient package.

What if someone brought the Swiss Army knife concept into the engineering lab and applied it to development tools? Imagine a development tool inspired by the Swiss Army knife and its ability to offer a number of tools for almost any situation you would encounter. This Swiss Army knife- inspired development tool would need to be available in a compact package and provide measurements across a wide bandwidth for a number of applications used in professional, maker, and academic environments. With all these capabilities, this one development tool could replace a number of test and measurement tools traditionally used in the lab. What could the scientific community do with a tool like this?

Well, one company has taken the challenge. That company is named Red Pitaya after a common dragon fruit—the Pitaya Roja, known for its red skin and flesh (Figure 3). Located not in Switzerland, but rather in Slovenia, Red Pitaya undertook an effort not to expand the Swiss Army knife but rather expand the development tools that electronic engineers have come to rely upon in the laboratory.

Figure 3: The red pitaya fruit alongside the corporate logo for Red Pitaya. (Source: Red Pitaya)

Focusing on areas concerned with science, technology, engineering, and mathematics (STEM), Red Pitaya created the STEMlab Starter Kit (Figure 4). The STEMlab is a mobile, multifunction lab instrument that users refer to as a Swiss Army knife for engineers.

Figure 4: The Red Pitaya STEMlab Starter Kit includes the accessories needed to start a project. (Source: Mouser Electronics)

This CE and FCC certified multifaceted tool supports the development of data acquisition and signal generation platforms, and SDR transceivers as well as electronics and FPGA programming learning environments. As such, the STEMlab Starter Kit is a handy lab instrument for engineers, hobbyists, makers, teachers, professors, and students. Available in two versions, the STEMlab 125-10 is perfect for universities, students, and makers while the STEMlab 125-14 is ideal for professional environments that require highly precise measurement results (Figure 5). Both versions offer the same features and functions but differ in their high-frequency input/output channels, RAM capacity, console connections, power consumption, and synchronization. The differences between the two versions are detailed below.

• The STEMlab 125-10 has 10-bit input/output channels and is capable of 256 values while the STEMlab 125-14 has 14-bit input/output channels and is capable of supporting 16,384 values.
• The STEMlab 125-10 has 256MB of RAM while the STEMlab 125-14 is equipped with 512MB of RAM.
• The STEMlab 125-10 requires a USB to serial converter for console connection while the STEMlab 125-14 uses a micro USB connection.
• The STEMlab 125-10 has a maximum power consumption of 5V, 1.5A while the STEMlab 125-14 has a maximum power consumption of 5V 2A.
• The STEMlab 125-14 can accommodate synchronization with a daisy chain connector (up to 500Mbps).

Figure 5: The STEMLab 125-10 offers 10-bits of resolution and is perfect for student, hobbyist, and maker projects while STEMLab 125-14 delivers 14-bits of resolution to support highly accurate measurement results in professional environments. (Source: Red Pitaya)

STEMlab, with its 50MHz frequency range and 14-bits or 10-bits of resolution, is a powerful and precise multifunction measurement tool that can replace a stack of lab instruments. STEMlab can support oscilloscope, signal generator, spectrum analyzer, Bode analyzer, logic analyzer (basic and pro), LCR meter, SDR transceiver, and vector network analyzer applications. Every application is web-based, free-of-charge, available when purchasing the board, and can be controlled remotely.

STEMlab provides high-performance measurements in a pocket-sized unit. It is built around a dual-core ARM® Cortex®-A9 processor with a field programmable gate array (FPGA) system-on-chip (SoC) (Figure 6). Customizable at both the FPGA and CPU levels, STEMlab can easily process real-world signals.

Figure 6: The Red Pitaya STEMlab diagram details the features on the development tool. (Courtesy of Red Pitaya)

STEMlab, when used as a data acquisition and signal generation platform, is a reliable partner providing great value and flexibility. STEMlab uses an open-source software platform available on GitHub. You can access device functionalities through Matlab, Labview, Scilab, and Python APIs. Thanks to its intuitive software design, many useful examples, and detailed documentation, STEMlab reduces the time required to develop new applications.

You can also use STEMlab as a 62.5MHz SDR transceiver. With its onboard analog-to-digital converter (ADC) operating at a speed of 125MS/s sampling frequency, it can digitize RF signals from the antenna. An in-phase/quadrature (I/Q) digital down-converter (DDC) running on the FPGA processes the data from the ADC. Transmission control protocol (TCP) transmits the I/Q data to the SDR programs such as SDR# and High Definition Software Defined Radio (HDSDR). Just add an all-bands filter and amplifier module, connect an antenna, and you are ready to start your SDR adventure.

STEMlab is also a great teaching and learning platform to gain a better understanding of FPGA programming and elementary electronic circuits. Readily available teaching materials make it easy for professors to create courses. The self-learning guide and well-documented step-by-step examples make home learning a fun exercise.

Using this highly versatile development tool you can transform a PC, tablet, or phone running Windows, Mac or Linux into a 2-channel oscilloscope, 2-channel signal generator, 8-channel logic analyzer, spectrum analyzer, LCR meter, bode analyzer, and vector network analyzer. All these capabilities make STEMlab a handy, multifunction tool for engineers, hobbyists, teachers, professors, and students developing data acquisition and signal generation platforms, SDR transceivers, and interactive STEM learning environments.

Although I have a lot of respect for Swiss engineers and their many inventive products, I also have to give credit to Red Pitaya. They found a way to recreate the Swiss Army knife idea into the ultimate multifunction lab tool for engineers. Others in the electronics industry agree. STEMlab received recognition as an Electronics Industry Awards Finalist (Figure 7). Now, I’m left wondering what engineering feat the Red Pitaya team will master next?

Figure 7: The Electronics Industry Awards named STEMlab a finalist in the Test, Measurement & Inspection Product of the Year category. (Source: Red Pitaya)