Raspberry Pi details compute module case studies

Raspberry Pi in the UK has detailed some of the industrial uses of its compute modules, from the CM3 to the recently launched CM5.

For example, synthesizer maker Korg in Japan is using Compute Module 3 (CM3) in its Wavestate, Modwave, and Opsix models.

This move to Raspberry Pi Compute Module came about when Korg R&D was trying to reach a sub-$1000 price point while still maintaining quality and fixing persistent technical issues along the way. Korg hoped this was the way to reach more musicians, and after using more traditional desktop and laptop-style chips to run the Linux operating system for over a decade, it realised Raspberry Pi Compute Module was the next logical step to help bring that price down.

This resulted in Wavestate, a successor to the 30-year-old Wavestation that uses a combination of two boards — one for the actual physical synth controls, and another that has audio subsystems and power — both of which connect to CM3.

“Not everyone understands that Raspberry Pi is actually making the sound — many people assume that it’s not,” Dan Phillips from Korg told Raspberry Pi. “We use CM3 because it’s very powerful, which makes it possible to create deep, compelling instruments.”

iPourIt is using CM3+ module for its latest automated system that lets customers choose their beer and pay using an RFID device linked to their tab. This system is very popular with businesses, as it allows for faster service, less wastage, and saves space.

The first systems were based on Android, but a redesign took the design from wireless to PoE (Power-over-Ethernet), simplifying the wiring in the process. Each touchscreen includes a CM3+ to control it, and every twelve taps are then controlled by one Raspberry Pi 4. The system allows for extremely accurate dispensing and now includes spirit and liquour dispensing.

“Right now we are probably 20% less expensive than our nearest competitor, so price-wise, how [Compute Module] has been designed has really allowed us to reduce the acquisition cost for our operators,” Darren Nicholson, CMO of iPourIt, told Raspberry Pi.

TBS supplies hotel chains with specialist systems that run the televisions in their rooms. These can stream channels and provide digital signage as well. While developing its new OBP-24 mini-server, one of the main requirements was the ability for customers to be able to add their own tuner card: “So we will be able to stream DVB channels, satellite, terrestrial, or cable through the whole local network,” said managing director Christian Kingler.

Maintaining a standard form factor was very important, but adding flexibility to adapt the device for different users was also a requirement. In early tests of the design, TBS used a Raspberry Pi 4 and found everything to be working just fine. After that, the firm started using Compute Module 4 and developed the PCB for the final product from there.

“It was quite attractive to have the CM4 IO board available… We were also able to test with this first, and then we made our own adaptation [for] what we needed in terms of form factor and PoE,” added Kingler. RP2040 was used for the little LCD control panel at the front of the OBP-24 and, thanks to further testing at an early stage using existing hardware, could also be adapted according to the company’s needs.

Homey in the Netherlands started life in 2014 as a smart speaker and home hub from the Dutch company Athom and is now part of LG.

While designing the recent Homey Pro, Athom wanted it to work with as many communication systems as possible — including Zigbee, Z-Wave, Wi-Fi, Bluetooth, 433MHz RF, infrared, and Thread — without needing the extra Bridge. It became a challenge to fit everything into the device.

“We didn’t want it to look like a gaming router with all these antennas sticking out,” said Emile Nijssen of Athom. “So getting that right took a long time. And we also wanted to profit from the development we did on Homey Bridge. So actually while designing Homey Bridge, which is sort of a light version of Homey Pro, even if you look at it from the outside, we already were thinking about how later on we could put our own carrier board on top of it that could carry, for example, a Compute Module.”

Some developers are using the CM4 as a path to higher performance with the CM5.

ELECROW in China has developed a 7in touchscreen terminal as a multifunctional industrial control device. This is initially based on the CM4 module for review, but the terminal is also compatible with the CM5. The interfaces include CAN bus, RS232/RS485, isolated digital I/O, differential input ADC, and relay control. There is also WiFi and BLE, with a Mini PCIe interface for 4G and LoRa connectivity. The semi-open structure features an acrylic shell, an IP65-rated front panel, and support for high-temperature operation.

Sfera Labs in Italy is using the CM4S module for its Iono Pi Max industrial controller, with a view to upgrading it to the CM5.

Another Italian developer, Seco, is using the latest version, the CM5, for a 10.1in touch display alongside its Clea OS operating system that is being integrated into the Raspberry Pi stack for applications in the Internet of Things (IoT).

Lime Microsystems in the UK is also using the CM5 to boost the performance of its 5G basestation in a box. This supports 5G NR TDD SISO operation with 10MHz RF bandwidth and FDD 2×2 MIMO with 20MHz bandwidth and is still able to run a 5G Core network also on the Compute Module for fully self-contained operation.