Lucky Resister‘s latest project is about an Arduino-based smart temperature monitor and pulse-width modulation (PWM) Fan Controller. It can simultaneously monitor the ambient temperature using two DHT22 sensors and control the speed of the two fans with minimal noise and at the lowest possible speed that is good enough to maintain the temperature to the desired value. The project also uses Adafruit’s datalogger shield, which contains a real time clock chip and an SD card slot, to record the sensor readings along with time stamps. An I2C LCD provides a nice user interface and displays time, temperature readings, and status of the fans.
Tag Archives: Thermometer
Organic light-emitting diode (OLED) displays are the coolest displays ever made. Check out this instructable on building an Arduino controlled OLED clock that uses a DS3231 RTC module for precise time-keeping. The DS3231 is a low-cost, extremely accurate I2C realtime clock (RTC) with an integrated temperature compensated crystal oscillator (TCXO) and crystal. The project incorporates a rechargeable battery to maintain accurate timekeeping during power failure. The implementation of an interactive menu system, which is navigated through two tact switches, the time setting becomes handy. The DS3231 module uses the built-in temperature sensor to compensate for clock drift due to temperature variation, which helps to keep the accuracy to 1 or 2 minutes/year. By default, the temperature is sensed and updated by the DS3231 once every 64 seconds. However, it is possible through software to update temperature reading and oscillator adjustment done as fast as 5 times/second. The temperature measurements are also displayed on the OLED clock screen. The author uses Adafruits Graphics library to drive the OLED display, which has the SSD1306 controller.
This DIY digital clock plus thermometer is designed by Joe Farr and is based on PIC18F25K22 microcontroller. The complete construction details of this project including circuit diagrams, PCB layouts and PIC firmware are posted in his website. He developed his firmware using Proton PIC BASIC compiler, which is available for download for free for this particular PIC microcontroller. He uses DS1302 RTC for timekeeping and DS18B20 for temperature measurement. The temperature and time are displayed on four 2″ seven segment LED displays.
This Arduino-based wireless thermometer uses two Arduino boards to measure indoor and outdoor temperatures. The outdoor Arduino board sends out the outdoor temperature measured by DS18B20 sensor to the indoor Arduino board using inexpensive 433MHz RF transmitter and receiver modules. The indoor Arduino board then displays the indoor and outdoor temperatures on a character LCD display.
In Tutorial 3, we learnt how to use chiKIT ADC channels to read an external analog voltage and convert it into a digital number. We also discussed about interfacing a standard Hitachi 44780-based character LCD to the chipKIT Uno32 board in Tutorial 4. Now it’s time to implement the knowledge we have gained so far to make our first practical application using chipKIT, which is a digital thermometer. Since temperature is a non-electrical entity, the first thing we need is a transducer or sensor to convert it into an electrical signal. In this project, we will use the LM34 sensor to do that, which converts the surrounding temperature into an analog electrical voltage. The sensor’s analog output is fed to an ADC channel of the chipKIT Uno32, which then process the signal and displays the temperature on LCD, in both degree Celsius and Fahrenheit scales.