Near-infrared spectroscopy device for measuring muscle oxygenation level. Research/semi-commercial project with main goal to make a device to research efficiency of various probe configurations and wavelengths for obtaining as much information as possible using variations in light absorption on different light frequency. Included WiFi transmission of obtained data and PC software for their recording and basic analysis. Device uses 4 wavelengths and two photodiodes, resulting in 10 simultaneous data channels (4 LEDs and one ambient light sensing for each photodiode), signal amplitude resolution on each channel is 14 bits, time resolution is 5ms.