This external sensor module measures air humidity (the sensor Honeywell HIH-5031-001), illumination (the sensor Broadcom/Avago APDS-9008-020) and temperature (with different temperature sensors: Texas Instruments LMT70AYFQR or LM35CA). The high-resolution environmental data logger is connected to the side connector of the EIS spectrometer and is used for monitoring environmental conditions during experiments. Overview of main parameters is shown in the following table
| sampling resolution (the EIS spectrometer) | 20-24 bit |
| min. resolution of analog input (the EIS spectrometer) | 64nV |
| conversion factor V/t of LM35CA sensor | 10mV/C |
| conversion factor V/t of LMT70AYFQR sensor | 5.19mV/C |
| conversion factor V/% of HIH-5031-001 | 23.5mV/% |
| measurement range of light sensor | 0-1000 Lux |
| size of data logger sensor pannel | 100x10x5 mm |
