DHTxx Sensors @ The Adafruit Learning System:
This tutorial covers the low cost DHT temperature & humidity sensors. These sensors are very basic and slow, but are great for hobbyists who want to do some basic data logging. The DHT sensors are made of two parts, a capacitive humidity sensor and a thermistor. There is also a very basic chip inside that does some analog to digital conversion and spits out a digital signal with the temperature and humidity. The digital signal is fairly easy to read using any microcontroller.
DHTxx Sensors Tutorial - [Link]
raph @ raphnet.net writes:
USBTenki is an electronic project to interface sensors to an USB port for collecting weather related data such as temperature. The firmware supports many different sensors and interfaces. It is up to you to decide what your USBTenki will support.
USBTenki: USB Temperature sensors and more - [Link]
USBTemp provides a thermometer. It is based on the DS18S20 digital thermometers. In addition, the thermometer connects to an USB port – you can read the temperature using a commandline tool. In combination with RRDTool you can easily create temperature graphs
USBTemp – USB temperature measurement - [Link]
- U-EC6 USB Emulator Debugger
- SHT11 Digital Humidity & Temperature Sensor
- Battery Holder
- Plastic Enclosure
Wireless USB Temperature & Humidity Datalogger - [Link]
The Temperature Candle is a relatively simple design which essentially boils down to a 8-pin microcontroller, a temperature sensor and voltage reference and a RGB LED on a 1.5″ diameter PCB – the same size as a standard votive candle. The micro flickers the LED like a candle at a color determined by the ambient temperature. The color gives an indication of the room temperature in reference to the recommended sleep time temperature for
babies to reduce the risk of SIDS (Sudden Infant Death Syndrome).
The candle can also blink the temperature by pressing a reset button on the PCB.
This should be a relatively cheap kit and it uses all thru-hole components so it should be easy to assemble. Using a simple micro, it can also be a good introduction to microcontrollers, and is designed with a jack to connect to Microchip’s Pickit 3 programmer / debugger.
You can see more information and look at all the design files on its project page.
The Temperature Candle - [Link]
There are quite a variety of active analog temperature sensor ICs that provide an output voltage proportional to the temperature. They usually don’t require any external calibration and signal conditioning, and as such their output can be directly fed to the input of an ADC for digital processing. A few examples of such sensors are LM34, LM35, TMP35/36/37, and MCP9701. If you are having any trouble using any of these sensors in your project, here is a quick way to test if your sensor is working or not.
Testing active analog temperature sensors with a multimeter - [Link]
Arduino Temperature Humidity Sensor @ PlastiBots – [via]
The projects I do tend to fall in one of two buckets – either proof-of-concept (so I can learn new stuff) or items that have some sort of functional use. The need for this project came about when my wife was prodding me about the humidity in the house and whether our humidifier was doing it’s job correctly. Most people would just go out and buy a temp / humidity sensor and be done with it. However, if you have a look around here, you will see that I don’t fit that mold. Instead, I decided to build an accurate temp / humidity sensor with a Sensiron SHT11 to read the values, a RBBB Arduino kit to process everything and an Adafruit 128×32 OLED to display the results – all wrapped up in… LEGO! Read on for more…
Arduino Temperature Humidity Sensor - [Link]
The temperature switch IC inverts the output according to the detected temperature, enabling a simple circuit configuration ideal for reducing costs and space in a system.
In a temperature switch that is configured using a thermistor, a comparison circuit is required downstream. However, this circuit is not required in SII’s temperature switch IC because the IC inverts the output when the detected temperature reaches a preset value. This makes the IC ideal for reducing costs and saving space in the customer’s system.
In the temperature switch ICs, the output is inverted when the temperature exceeds the set value.
The following temperature switch ICs are available: a latch type that maintains an inverted state (latch) to prevent an unstable output at the detected temperature and a hysteresis type that releases the inverted state when the temperature decreases to the set value.
S-5840B / S-5841 – Temperature Switch ICs - [Link]
Geoff designed this USB PC case fan controller. It is used to control the speed of your fans depending on the temperatures in your case. Software that was developed for this project allows you to customize the temperature profiles for your computer.
The project is based on the PIC18F2550 that is connected to the computer via the USB and uses the standard Molex 4pin connector to access computer’s power supply. It has 4 analog inputs for temp sensors, and can control up to 8 fans.
One thing to note is that all the fan outputs work with 3 pin fans, while two are universal and work even with 4 pin PWM versions. The 3 pin fans are driven with a buck convertor. The UDN2981 provides the high side switch and diode that are driven from PIC’s PWM signals. A 100uH inductor and a 479uF capacitor complete the buck topology, thus providing variable analog output for the 3 pin fans.
Intelligent Fan Controller - [Link]
Today we did a quick test of the TMP006 infrared non-contact temperature sensor with an I2C interface. Point it at something and it measures the temperature. We were expecting a simple breakout board we could test with the Bus Pirate, but got full USB-enabled evaluation kits. To use the Bus Pirate with this board check out Joe’s tutorial. You might get this kit if you leave a comment on yesterday’s giveaway announcement (comments on this post will not be considered).
The evaluation kit has two parts: a USB module that presumably works with many different TI breakout boards, and the TMP006 sensor board. The sensor is only available in a BGA8 package, so a breakout board like this is the only way many people can use the sensor. It’s available from Digi-Key in 1s, so we could sell a simple breakout board if you’re interested.
TMP006 infrared temperature sensor test - [Link]