praveen @ circuitstoday.com posted a project on a Temperature logger using Arduino:
This project is about a simple USB temperature logging system using arduino uno and the serial monitor function in the arduino IDE. The system monitors the temperature every 2 seconds and shows it on the arduino serial monitor. The temperature is shown in °Celsius and °Fahrenheit. The system is interfaced to the PC through the USB port. LM35 is used as the temperature sensor.
LM35 is three terminal linear temperature sensor from National semiconductors. It can measure temperature from-55c to +150C. The voltage output of the LM35 increases 10mV per degree Celsius rise in temperature. LM35 can be operated from a 5V supply and the stand by current is less than 60uA. The pin out of LM35 is shown in the figure below.
Temperature logger using Arduino - [Link]
Mizchief100 @ instructables.com wanted a way to control with dorm air conditioner so he build an Arduino thermostat that controls the control knob using a servo motor:
I am currently living in a college dorm. Like most dorms it’s about the size of a tissue box but less comforting. Fortunately, my room has a heater/AC with four positions: low, medium, high, and off. Unfortunately in winter an hour on the low setting makes the room a stifling 80 degrees and when turned off it drops quickly to 60 degrees. My solution uses an arduino, temperature sensor, and motor to automatically turn the heater on/off to keep the room within a desired temperature range. Not only is this more comfortable but it dramatically reduces the time the heater is used, saving lots of energy. (Also note that the motor is only driven to switch the setting and then turned off so no holding energy is wasted.)
Arduino Thermostat (Mechanical) - [Link]
Complete digital temperature sensor Sensirion STS21 provides a top-level accuracy and stability for a very affordable price.
Digital sensor STS21 s the newest member of calibrated humidity and temperature sensors family SHT2x (SHT21, SHT25). In opposite to them, STS21 is able to measure only temperature, i.e. it´s suitable only for applications, where we don´t need to measure humidity. However a smaller functionality has also a significant positive aspect in a form of a substantially lower price. STS21 contains on a chip, similarly like its familiar, a temperature sensor, precise supply, low noise linear amplifier, AD converter and a serial interface with I2C output (fixed address different from SHT series).
Basic accuracy of STS21 in the 0 to +60°C temperature range is +-0.2°C. The user can choose a resolution for measuring and it can be 11-14 bits (up to 0,01°C). Despite the fact, that the sensor hasn´t guaranteed absolute accuracy of 0.01°C, such a high resolution can be beneficial for example for monitoring of a tendency (increasing/ decreasing) of temperature.
Detailed information can be found in the Sensirion STS21 datasheet.
STS21 measures temperature with an 0.01 °C resolution - [Link]
The MAX31730 temperature sensor monitors its own temperature and the temperatures of three external diode-connected transistors. The operating supply voltage is from 3.0V to 3.6V. Resistance cancellation compensates for high series resistance in circuit-board traces and the external thermal diode, while beta compensation corrects for temperature-measurement errors due to low-beta sensing transistors.
MAX31730 – 3-Channel Remote Temperature Sensor - [Link]
Kerry Wong writes:
In this post, I will show you yet another thermometer/hygrometer build. But instead of using an LCD or 7 segment display for the output, I decided to go retro, using two “needles” to display the temperature and humidity readings instead. And to make the project more fun, I did not use analog meters for the output but chose to use two servos instead. The temperature humidity sensor I used is SHT21 from Sensirion, the same sensor I used in my temperature logging project before. In that project, the temperature and humidity readings were sent over the network and displayed on my web server (you can see the current readings in my lab here).
A digital thermometer hygrometer with analog displays - [Link]
This project consist of Arduino board, serial TFT LCD 128×160 display, DHT22 sensor and obviously bread board and jumpwires.
- Temperature measurements : -40 – 125° C, +/- 0.2° C
- Humidity measurements : 0 – 100% , +/- 5 %
- Update rate 2 s
- Humidex(“describe how hot the weather feels to the average person, by combining the effect of heat and humidity.” ) is calculated based on measurements
- Humidex digits color varies and represents affect on humans.
- Black and white display themes.
Arduino based Temperature and Humidity/Humidex meter with DHT22 sensor and color LCD - [Link]
This project is a temperature controller for a PC FAN. It regulates the speed of the FAN attached to it according to measured temperature. Temperature is sensed using a simple NTC thermistor.
In most PCs the fan runs constantly, which may not be necessary. A simple circuit can regulate the fan speed according to temperature. This not only saves energy, it also reduces fan noise. Only three components are needed to allow the fan speed to be controlled according to the actual temperature: one adjustable voltage regulator (LM317T) and two resistors that form a voltage divider. One of the resistors is a NTC thermistor (temperature-sensitive resistor), while the other is a normal resistor.
Temperature Controlled PC FAN - [Link]
The Si7005 is a digital relative humidity and temperature sensor from Silicon Labs. It integrates fully factory-calibrated humidity and temperature sensor elements with an analog to digital converter, signal processing and an I2C host interface in a single monolithic CMOS sensor IC. The Si7005 is available in a “non hand-assembly-friendly” 4×4 mm QFN package, which requires reflow soldering to mount it on a PCB
Breakout module for Si7005 temperature and humidity sensor - [Link]
The team describes it as the world’s first starter-kit designed for App Developers to build apps, for the devices and things around them. A “chocolate bar” with detachable bits of different sensors and Bluetooth Low Energy, connected to a mini wifi base, together with easy-to-use SDKs for iOS, Android, node.js, and our simple REST API.
The WunderBar is the easiest way to create useful connected devices. It works out-of-the-wrapper, contains a host of awesome sensors, and is dead-simple to program.
Sensors include: Light, color, distance, temperature, humidity, remote control (IR), accelerometer, and gyroscope. Two additional sensors will be chosen by you.
WunderBar – Internet of Things Starter Kit for App Developers - [Link]
bogdan @ electrobob.com wanted to know how much heat a heatsink can dissipate so he build a simple setup using a temperature sesnsor and a mcu. He writes:
It’s quite a common problem when building electronics that some components need cooling which is usually done through some sort of heatsink and optional fans. Choosing the right cooling solution can be a difficult task because the real life behavior of the system is hard to predict or model. In my case I have faced the simple question quite a few times: how much heat can a cooling system dissipate? The thermal resistance of a particular heatsink may vary quite a lot depending on the surroundings or it can simply be unknown to start with. The aluminum side wall of an enclosure made me build this thing.
This is why I have made this little device: a thermometer, a transistor and a microcontroller with a simple command line interface. I could have answered my questions in quite a lot of simpler ways, but since I made a simple thermometer not much else is needed to control the transistor when a DAC is available in the microcontroller.
Heatsink Tester - [Link]