IGN has developed low-cost accelerographs known as Silex, based on MEMS technology, for the detection and recording of earthquakes with magnitudes which can be perceived by human beings. A network of these devices has been deployed in Spain, particularly in areas with relevant seismic risk.
Two of such devices are installed in Yebes and Santa María RAEGE stations and another two have also been installed in Ny-Alesund (Svalbard, Norway) and Metsähovi (Finland) observatories.
More information can be found here.
SILEX accelerometer installed in Metsähovi Observatory (Findland)