GEOtiny20 is a compact miniature digital seismometer that integrates three seismic and three acceleration channels. It supports high-resolution 24bit digitizer, embedded linux OS and GPS or NTP timing. Seedlink server ensures reliable real-time data telemetry while large storage volume ensures long period local data recording. The instrument has very low power consumption so it can operated by getting power from a small 12Vdc battery. Due to its small size provides the ability to be buried underground. Modular sensor interface allows the user to select between a variety of sensor types and frequency corners (20sec, 10sec, 5sec, 2sec, 1sec, 2Hz, 4,5Hz), thus covering the short period and wide-band seismic range. Design simplicity is a great advantage and it is reflected in the price which is the only fraction of the common commercial seismometers. The user is able to deploy even 100% more units than using common seismometers at the same cost.