Earlier I presented a project on how to measure temperature with a LM35 and an Atmega8 microcontroller and display it on LCD. In the current project an Arduino board is used and the temperature reading is sent to a PC. A software is written for PC to display the data received on USB from the Arduino. It shows temperature value both in Celsius and Fahrenheit, numerical and as a bar-graph and a histogram with 100 data points.
The sensor is connected to one of the analog inputs of the Arduino. The code for microcontroller is very simple since all it does is convert the analog output of the sensor to digital and send it to PC and it does that every second.
The PC software is written in Processing, all code is available in the link.
Arduino Thermometer: [Link]
Here is a very good looking thermometer project showing the reading as a discrete value and as a bar-graph on a LCD. The idea is simple, we have a sensor, the LM35, who outputs a voltage depending on the ambient temperature, LM35’s rating is 10mV/ degree Celsius. Since the sensor’s output is analog we need to convert it to digital in order to display the value on LCD. The ATmega8 microcontroller will handle the A/D conversion, with a 4.8mV resolution it is within the accuracy range of the sensor.
Once the LM35’s output has been converted to digital, the microcontroller will make the calculations necessary to determine the temperature and display that value. The LCD is a 20×4 type so the bar-graph will show 20 levels. ATmega8’s port C0Â reads the analog data from the sensor and port D controls the LCD. The code was written in BASCOM AVR which has some built-in functions to handle the A/D converter of the microcontroller. For Fahrenheit measurement use LM34 sensor.
All in all it is easy to build, as a school project perhaps,Â with possibility for upgrade, for example to be able to change the bar-graph’s scale.
Digital Thermometer: [Link]
This project was send to us by Bob Ashlock, who is rightfully proud of his achievement, he made a temperature gauge with the LM34 sensor and PIC16F684. He inspired he’s project from this PIC16F84 thermometer that was posted here on youritronics. The sensor has 10mV/F output, not to be mistaken with the LM35 which has 10mV/C output, but the firmware can be easily adapted.
The source codeÂ is well documented, but there is room for optimization, yet taking into consideration that this is Bob’s first project and he learned by himself its a great code. The outcome looks very nice and has its practical use, he used to measure the air and oil temperature in his 66′ Porsche. In the download you have the schematic and source code written in C.
Great job, and thanks for sharing with us your project and experience.
Car temperature gauge: [download]
The LM35 of National Semiconductors that is used in this project is a precision centigrade temperature sensor, which has an analog output voltage. It has a range of -55ÂºC to +150ÂºC and a accuracy of Â±0.5ÂºC . The output voltage is 10mV/ÂºC . The output voltage is converted by the AD convertor of the ATMega8. The temperature is displayed on an LCD module. In this example the thermometer has a range of 0ÂºC to 40ÂºC and a resolution of 0.5ÂºC. If you want to have a readout in Fahrenheit you can use the LM34.
LM35 Based Thermometer Display Temperature on LCD: [Link]
These days more and more temperature sensor projects appear on the internet so the world must be in need of temperature sensors ðŸ™‚ . Daniel got hi’s done and up on the blog. The project is based on the LM35 Precision Temperature Sensor and the Arduino. He also plans on building a temperature sensor with max/min + clock and LCD, he promisses to post it on the blog when its finished.
Arduino Temperature Sensor: [Link]