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temperature sensor using 8051 microcontroller to pc visual basic

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Moderators: Ajay, Junied , abbas1707, Arun Kumar V, pdi33, Shailesh NAYAK, ۞ TPS ۞, shyam, sashijoseph

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mic_k86

Tue Jun 03 2008, 12:20AM

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hi,

i have a project of a temperature sensor network. the concept is a temperature sensor sense the water temperature and transmit the temperature value to display and store at pc. it is a project combine of hardware and software. i plan on using 8051 microcontroller at the hardware part and visual basic 6.0 at the software part. but i am weak at writing the 8051 assembler coding the the visual basic coding. anyone in this forum can help me pls...

thanks

sashijoseph

Tue Jun 03 2008, 01:25AM

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What sensor have you decided for water temp?
You would need to interface the sensor to an ADC first.Look here for a tut on 8051 interfacing to an adc. http://www.8051projects.net/adc-interfacing/

Next you will have to pass on the logged values to the pc through the serial port.
Here's a tut on serial interfacing. http://www.8051projects.net/serial-communication/

Finally VB program on the pc side for collecting data from the serial port.Look here..
http://www.8051projects.net/forum-t5021-0.html#post_5060

Let there be music........

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mic_k86

mic_k86

Wed Jun 04 2008, 11:46PM

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thanks sashijoseph.

i am using temperature sensor DS18S20 for this project. But i have problem for the connection. the pin no.2 (DQ) of the DS18S20 need to connect to which pins of the ADC0804? If direct connect DQ to pin 6 and ground pin 7 of ADC0804 will work? But at some website i found that they mentioned about transducer at this part connection. So what is the correct connection?

thanks

abbas1707

Thu Jun 05 2008, 03:05AM

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DS18S20 is digital thermo meter so no need of aany ADC. for what you are using ADC??

A Thousand Miles Journey Starts With a Single Step.

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mic_k86

mic_k86

Thu Jun 05 2008, 11:51PM

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so means that direct connect the pin 2 (DQ) to microcontroller 8051 should be ok? but connected to which pin at 8051? Is that pin no.17? Coz i found that only this pin have RD. How to connected for multiple DS18S20?

thanks

abbas1707

Fri Jun 06 2008, 12:35AM

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you can connect it to any pin of 8051 which is an i/o pin. then 1 wire protocol will be used for communication b/w sensor and controller. you can connect mutiple ds18s20 on a single 1-wire bus.pullup has to be used b/w them and controller

A Thousand Miles Journey Starts With a Single Step.

mic_k86

Sat Jun 07 2008, 12:16AM

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What you mean pullup in this case? Is that connected multiples ds18s20 with external power supply instead of parasite power? Is it possible to connect different ds18s20 to different i/o pin?

abbas1707

Sun Jun 08 2008, 05:31AM

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pullup resistor. it is possible to connect different ds18s20 to different i/o pins but it will...be totally a bad design.you have to follow the standard way which is 1 wire bus

A Thousand Miles Journey Starts With a Single Step.

mic_k86

Sun Jun 08 2008, 06:29PM

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erm...can you give me an example of circuit diagram on how to connect in pullup resistor? If using parasite power for DS18S20, the Vdd pin is connected to ground or leave it not connected?

Ajay

Sun Jun 08 2008, 08:36PM

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Pullup is something like this...
VCC |----/\/\/\/\---->Pin

vdd can be connected to ground if you are using parasitic mode of power but do not forget to add a mosfet for pullup. which is needed most.

Please read datasheet for more information on pullup requirements.

www.rickeyworld.info
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