You may have read the recently published article on Red Pitaya Working in Antarctica, in which HF radio signals were sent for data transmission in Antarctica using the setup shown in the following schematic diagram.
Figure 1 Red Pitaya Working in Areas in Antarctica
There was also an article on Transmitting Video Signals Using (Ultra-)Sound Waves, for video streaming with digital signals sent via ultrasound waves through solid material. Certainly an eye-catching application!
Figure 2 Transmitting Video Signals Using (Ultra-)Sound Waves
Finally, the article on a PiRadar Project Connecting Low-Cost Radar Nodes for Ionosphere Imaging presented a radar system transmitting and receiving HF signals for ionosphere probing and imaging through a vast array of radar nodes.
Figure 3 PiRadar Project Connecting Low-Cost Radar Nodes for Ionosphere Imaging
The varied applications show that these are three fairly different projects, but with one common element (or rather two), easily spotted after looking at the diagrams for a few seconds: the cores of all three setups combine the STEMlab’s I/Os and sampling capacity with Raspberry Pi control features. Since there are probably many other similar projects with this same feature, you might wonder what would happen if you could bundle their functions together into one single component. The answer is simple: with Red Pitaya, it’s already possible.
Admittedly, the Raspberry Pi 4 is a versatile product for general computing tasks for extremely moderate budgets, and may be slightly easier to configure, but when you want your setup to actually measure and/or control a process, you’ll eventually end up integrating an FPGA or similar. Adding the user-friendly configuration of a STEMlab 125 to the built-in FPGA, together with the open-source specialized apps and the multiple connectivity options, and you get a complete system that can tackle much more than just your average kitchen-table project.
Let’s have a quick recap of the functions performed by the Raspberry Pi 3 units that were directly connected to the STEMlabs in the three experiments cited above, and see whether these could have been taken over by the Red Pitaya boards. In the South Pole data transmission setup, the Raspberry unit connected to a GPS system, Teensy module, and external hard drive. In the video streaming project, it captured, compressed, and packetized the camera signal on the transmitter side, and delivered the video stream on the receiver end to remote users via a router. Finally, in the PiRadar nodes network, the Raspberry received the 32 Mbps data stream from the STEMlab for storage in a USB HHD data archive or transmission to a remote user.
Red Pitaya boards can easily connect to GPS and Teensy modules via the USB port or UART pins on the GPIO header, among other ways. External memory drives can also be connected to the same USB port. However, for the video application the capturing and compressing feature would not work directly on the STEMlab, which would at least need an external video capture device, such as a USB- or PCIe-based HDMI or SDI capture card.
Should this article now be considered an attempt to diminish the abilities of Raspberry units? Not in the least. Actually, Raspberry and Red Pitaya have a common philosophy that lowers the tech project threshold for students, educational institutes, hobbyists, and others, offering an invaluable and ever-growing community of users sharing their experiences. But where Raspberry is, as stated before, an excellent platform for general computing tasks, Red Pitaya opens a specific range of options that allow high-performance operation for control and measurement tasks.
So what we’d like to point out is that sometimes the use of certain key components in an experiment is not fully optimized, and these same elements could actually be performing some of the functions of other building blocks that were perhaps integrated because they seemed a more obvious choice at the time. But engineering is also a matter of minimizing project size and cost, including optimizing the use of components, and thus pushing boundaries.
More detailed technical specifications, including a comparison between the most relevant Red Pitaya boards and the Raspberry Pi 4, can be found in the following article: https://redpitaya.com/raspberrypi/.