Temperature Sensor based application

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Anonymous
Not applicable

I need to develop a temperature sensing controller demo. This system will be installed in a vehicle which carries food products across locations. The temperature needs to be changed based on the food product i.e. different temperature for milk products, fruits etc. Can you suggest which kind of sensor will be suitable - Thermistor, Thermocouple or diode for this application?

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13 Replies
Bob_Marlowe
Level 10
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Have a look here

   

http://www.cypress.com/?rID=61127

   

http://www.cypress.com/?rID=51626 

   

http://www.cypress.com/?rID=63613

   

or here http://www.cypress.com/?docID=25376.

   

all found with a keyword search "Temperature sensing"

   

 

   

Happy coding

   

Bob

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ETRO_SSN583
Level 9
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Should you have a requirement for non contact temp

   

sensing Melexis and TI offer IR T sensors -

   

 

   

http://melexis.com/Products-By-Category/Infrared-Thermometer-Sensors-155.aspx

   

http://www.ti.com/ww/en/analog/tmp006/index.shtml?DCMP=hpa-tmp-tmp006&HQS=Other+PR+tmp006-pr

   

 

   

These tend to be more expensive soplutions, however.

   

 

   

Regards, Dana.

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Anonymous
Not applicable

 Hi Bob,

   

I did have a look at the links and from the block diagram in the link - http://www.cypress.com/?rID=61127, it is clear that we can use different types of temperature sensors, but the criteria for the selecting the sensor is not mentioned there. Could you give me some pointers as to how we can select the sensor? 

   

I am pretty new to this domain and am still doing a feasibility study therefore any sort of information would be useful.

   

 

   

Thanks

   

Shenaz

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Bob_Marlowe
Level 10
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I am not veryx experienced with Temperature sensors (programming is my main-task). As far as I know:

   

Thermocouples are best for higher temperatures, inherently precise, the signal has a low amplitude (V/degree) could be noisy due to the needed amplification.

   

PTCs and NTCs are cheap but unprecise and need calibration, are aging, but are usefull within your estimated temperature range. Repeated calibration needs some software and hardware and regular checking.

   

Measuring precisely the junction temperature can be made, but ther is one thing I find disturbing: the large (for electronic equipment) distance between the measurement point(s) and the device to set / control the required temperature.

   

So I would suggest a complete different solution: Use a (or more) thermo-sensor(s) with I2C interface at lower frequency (shielded cabling) and connect it to a PSoC with an LCD and a keypad. A simple proof-of-concept can be made easily with a cheap PSoC1 development board.

   

 

   

Bob

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Anonymous
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The range of measurement will be low for this application. Thermistor would be a good choice.

   

How is the mechanical setup -

   

1. where will be the sensors and actuators positioned?

   

2. where will be PSoC located?

   

regards,

   

Rajiv Badiger

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Anonymous
Not applicable

Hi Shenaz,

   

Alot of refrigerators use thermistor as the temperature sensor.

   

To use a thermistor with the PSoC1 you can refer to AN2017 here http://www.cypress.com/?rID=2606

   

--
Aditya

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ETRO_SSN583
Level 9
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Since this is a food/trucking application, one of the easiest and inherently

   

linear would be an LM334/335 type sensor. The LM334 is a current sensor,

   

can be used over long cable runs being a current device, and with a resistor

   

to convert I to V, and PSOC A/D, and a simple equation to calculate T, its

   

trivial to implement. Very linear, and initial uncalibrated accuracy of +/- 3

   

degrees C and low cost from LTC. The 335 is a V type sensor, so more

   

appropriate for shorter distances. .5 C initial accuracy part is AD592 from

   

analog devices, a current part.

   

 

   

Of course diode is the cheapest sensor http://www.ti.com/lit/an/sboa019/sboa019.pdf

   

 

   

Go to ti for a borad selection of sensors. http://www.ti.com/paramsearch/docs/parametricsearch.tsp?family=analog&familyId=611&uiTemplateId=NODE...

   

 

   

Then there is always integrationg into vehicle system, via CAN, LIN....

   

 

   

Then there is a plethora of serial buss parts, cabling adding cost to handle

   

high noise environment.

   

 

   

Regards, Dana.

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Bob_Marlowe
Level 10
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Yes, the answer seems to be as usual: "That depends on..."

   

The temperature range

   

The precision

   

Ease of use

   

Noisy environment

   

Cable length

   

Price

   

 

   

 

   

Bob

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Anonymous
Not applicable

Hello All

   

Really appreciate your help in providing answers. The sensors suggested, reading material links are really useful.

   

Bob, here are the few specifications

   

   

The temperature range - -50 to 50/60

   

The precision - +/- 0.5 (there is no need of high precision as it is a low cost application)

   

Cable length - around 20 m

   

Price - Not fixed but should be a low cost application.

   

 

   

Thanks

   

Shenaz

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ETRO_SSN583
Level 9
Level 9
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Here is a guide that might help. Current sensor probably best approach,

   

save Cu costs, 2 wire, handle long distances. You would have to do simple

   

computation of compliance V for the sensor.

   

 

   

http://ww1.microchip.com/downloads/en/DeviceDoc/21895d.pdf

   

 

   

There are several guides here, including an automotive solutions guide -

   

 

   

http://www.ti.com/analog/docs/selectionguides.tsp?familyId=353

   

 

   

Regards, Dana.

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ETRO_SSN583
Level 9
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Here is a TI selector tool for 2 wire sensors that might be useful -

   

 

   

      http://focus.ti.com/paramsearch/docs/parametricsearch.tsp?family=analog&familyId=611&uiTemplateId=NO...

   

 

   

Regards, Dana.

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Anonymous
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 Thanks to all for providing me with a lot of useful information.

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megog939
Level 1
Level 1
First reply posted Welcome!

Certainly! A Temperature Sensor-based application utilizes sensors to monitor and manage temperature levels in various settings. 🌡️ This technology finds applications in climate control systems, industrial processes, and even in smart homes. By integrating sensors with the Internet of Things (IoT), real-time temperature data can be collected and analyzed, allowing for efficient temperature regulation. 🏠🌐 This innovative approach ensures optimal conditions, energy efficiency, and enhanced user comfort. Now, if you're craving something as intriguing as technology, explore the Jack in the Box secret menu for a delightful culinary experience!

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