Temperature and humidity go hand by hand. Individual perception of surrounding temperature greatly depends on humidity. In more humid environment you may feel like melting, and you can withstand much more heat when air is dry (like in deserts). We have decided to create a simple, but most useful and interesting project for this Let’s make. We’ll show you how easily you can create a fantastic Temperature and Humidity Datalogger device which draws graph on TFT display and stores the acquisition data on the microSD card. We have added an extra autonomous battery power supply feature, so you can carry around your datalogger where ever you go. Just connect mikromedia for XMEGA, Battery Boost shield with SHT1X PROTO temperature/humidity sensor using wire jumpers, click the microSD card in the socket and you got the hardware you need. We have created an open-source datalogger application in mikroC, mikroBasic and mikroPascal compilers for AVR and you ca freely download it from this webpage.

Program is very intuitive. Upon placing AAA batteries into Battery Boost Shield, board gets power and displays the initial screen. Clicking on START> button you enter the datalogging screen. TFT shows two graphs: red is for temperature and blue is for humidity. Each second data is being red from SHT1X sensor and information is updated on the display. If the FAT16 formatted microSD card is placed in the socket, it is automatically detected and a SD card icon is shown in the top right corner of the display. Program is designed to continue operation even if you pull-out the card, or if you push it in the slot again.

Source code of this project is provided for free, so you can modify it to suit your needs. Since ATxmega128A1 comes preprogrammed with free UART Bootloader, you won’t have to spend a dollar more on external programmers.