The Raspberry Pi  is a small single board computer. It comes with an ARM based CPU (64 bit, quad core). You can buy it for $35 (no case included). The 4GB RAM version retailes for $55. Raspberry Pi runs some form of Linux. It is mainly used for educational purposes.
SCIP  is a solver for MIP (and related) models. It is only easily available for academics, using a somewhat non-standard license. As a result, I don't see it used much outside academic circles. So it can not really be called open source.
SCIP on Raspberry Pi
In  SCIP is used on the Rapberry Pi with 4GB of RAM. They call it an example of "Edge Computing": bring the algorithm to where it is needed  (opposed to moving the data to say a server).
On average SCIP is 3 to 5 times slower on an (standard or overclocked) Rasberry Pi than on a MacBook Pro laptop.
Of course the small amount of RAM means we can only solve relatively small problems. (These days what we call a small MIP problem is actually not so small).