Testing Antonki Thermometer/Hygrometer

 Antonki Thermometer/Hygrometer is sold at $8 for two.  It claims a temperature range of -50 to 70°C (-58 to 158°F) with accuracy +/-1°C and relative humidity range 10% to 99% with accuracy of +/-5%.

We use SHT31 and HTU21 breakout boards with Arduino Nano and an OLED display module (0.96" OLED 128x64).  Arduino 3.3V output is used to power the sensors and the display.  Very quickly, we pull together the code needed to read from the sensors and display the data on the OLED module.  It shows the power of Arduino.   We update the reading every 3s.

 For temperature, we also have the analog thermometer, thermocouple, and PRT measured by multimeter, and Fluke non-contact  IR thermometer. 

 We test in about 4 temperature settings, ambient (about 22C), refrigerator (3C), freezer (-18C), heater (50C).

Here are the results.

Antonki	-15.9	5.5	22.2	46.5
HTU21	-17.3	5.8	22.6	46.5
SHT31	-17.1	5.5	22.4	46.6
TC	-21	3	18	46
PRT	-17.4	6	22.8	48.5
Thermometer	-19	3	22	51
Fluke	-16.4	4.2	22.5	46.5

We compare a few humidity readings.

Antonki	55	31	71
HTU21	46.5	26.2	59
SHT31	56.4	34.6	69.4