We propose a teaching resource that uses HardKernel boards to build an MPI server with 256 cores. Although this system has a relatively low performance, the aim is to provide access to hundreds of cores for carrying out scalability analyses, while obtaining a good trade-off between performance, price, and energy consumption. Here, we give details about the implementation of this system at both the hardware and software levels. We also explain how it was used to teach parallel programming in a university degree course, and discuss the teachers’ and students’ comments about using this new system.