First real project I want to assemble is measuring temperature of water on my furnace in my basement. The project is very simple, one digital thermometer DS18B20 with oneWire interface will be conected to the board that I built. It will measure temperature and it will send it trough RS232 to Arduino Uno which will display it on a HD44780 LCD. I recently assembled a testing model:

The model works exactly like it should 🙂 On the photo we can see three boards. The big one in the bottom is there because it has a DS18B20 temperature sensor build in.

The board in the upper right side of the photo is connected to the sensor, it displays the temperature on the lcd on the right and it sends the value as ASCII characters to the arduino uno on the left side. Arduino displays the temperature on the lcd on the left. The arduino board is connected to the DHT22 sensor and it reads relative humidity and temperature as well. The DS18B20 sensor reading is displayed on the left upper side of the left lcd and it is the same as on the right lcd, those are the same readings.

Most important thing is that any of function doesn’t use a delay function 🙂 On the breadboard are two buttons which turn on lcd leds for approximately 10 sec.