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27 Apr 2012

embedded-lab.com writes:

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]

17 Apr 2012

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]

14 Mar 2012

sii-ic.com writes:

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]

3 Feb 2012

dangerousprototypes.com writes:

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]


2 Feb 2012

dangerousprototypes.com writes:

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]

2 Feb 2012

Michael writes:

My name is Karel and I’m creating an open source temperature controller. Please see the FAQ for open source licenses. I initially started this project because I make my own prototype PCBs at home, using the toner transfer method, and found out the laminator I use, a Scotch TL-901, doesn’t run hot enough and it took several passes to get the board hot enough. Instead of taking the time to reverse engineer the control board that was in the laminator, I decided to make my own.

After I finished the first prototype, I quickly realized there could be a lot of uses other than controlling a laminator. Some that came to my mind included using the board to modify a window A/C to be used in a walk in cooler, measuring inside and outside temp to control a green house, using it to control an aquarium heater, or even controlling egg hatching. I’m sure there are lots of other uses that the open source community will find.

Open source temperature controller - [Link]

30 Jan 2012

Charalampos Andrianakis writes:

DHT-11 is a temperature & humidity sensor in one package. It utilizes exclusive digital-signal-collecting-technique and humidity sensing technology, assuring its reliability and stability. Its sensing elements is connected with 8-bit single-chip computer. Every sensor of this model is temperature compensated and calibrated in accurate calibration chamber and the calibration-coefficient is saved in type of program in OTP memory, when the sensor is detecting, it will cite coefficient from memory. Small size & low consumption & long transmission distance(20m) enable DHT-11 to be suited in all kinds of harsh application occasions.

DHT-11 & One wire bus - [Link]

23 Jan 2012

unusualelectronics.co.uk writes:

I needed to replace two old, unreliable thermostats for controlling the heating and cooling for a large garden shed.
Commercial basic digital thermostats are available quite cheaply, but some lack the ability to control heavy loads or have the extra features that I require for saving energy when the door is often left open or to indicate temperature being out of range etc.

I like the PIC18F1320 microcontroller used in my previous project – so decided to use it again in a very similar design to drive three multiplexed LED displays and read the temperature from a Dallas/Maxim DS18x20 “1-Wire” digital sensor.

Digital Thermostat with LED Temperature Display - [Link]

22 Jan 2012

Temperature sensor – A trip to Steinhart-Hart, Gaussian elimination and thermistors @ skytee – [via]

I made a thermistor-based, water-resistant temperature sensor to be used with a micro controller. Here I document the process on how to get the thermistor calibration data.

Recently, my friend w0z visited after 28c3 and we ended up checking out Segor, a brick-and-mortar electronics shop in Berlin. It’s to me like a candy shop is to kids. Among other things, athermistor module picked my interest, mostly because I had never used one before.

The thermistor module I got came as a thermistor and an op-amp on a PCB. I hooked it up to an Arduino’s analog input pin and sure enough I could see the input data change when I exposed the sensor to warm air.

A really good summary of how to use thermistors and solve the Steinhart-Hart equation.

Temperature sensor – A trip to Steinhart-Hart, Gaussian elimination and thermistors - [Link]

12 Jan 2012

embedded-lab.com writes:

Measurement and control of temperature and relative humidity finds applications in numerous areas. These days devices are available which have both temperature and humidity sensors with signal conditioning, ADC, calibration and communication interface all built inside them. The use of such smart sensors greatly simplify the design and reduces the overall cost. We discussed in past about Humidity and temperature measurements with Sensirion’s SHT1x/SHT7x sensors. These sensors are capable of measuring both temperature and relative humidity and provide fully calibrated digital outputs. While  SHT1x/SHT7x are very accurate sensors, they are still expensive for hobbyists use. This articles discusses the DHT11 sensor which also provides calibrated digital outputs for temperature and humidity but is relatively lot cheaper than the Sensirion sensors. The DHT11 sensor uses a proprietary 1-wire protocol which we will be exploring here and implementing with the PIC16F628A microcontroller that will receive the temperature and humidity values from the sensor and display them on a 16×2 character LCD.

Measure temperature and humidity using DHT11 sensor and PIC - [Link]



 
 
 

 

 

 

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