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Hot!LCD thermostat with PIC16F1947

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JohnNovak
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2021/01/05 03:09:02 (permalink)
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LCD thermostat with PIC16F1947

Hi to all members.
I join to this forum because i wish to research some programming options with the device i have a problem.
This device is LCD touch screen room thermostat.
 
The microcontroller used in this device is PIC16F1947-I/PT.
I never read or write any PIC so i have no any experince with that.

Maybe any member on this forum have some experience with this devices.
The problem which is factory programmed is temperature difference or hystersis, the minimum setting is 0.5C (degree celsius)
which means 1.0C between on and off function which is very low sensitivity for home use.
I wish to have more sensitive digital thermostat with 0.1C or 0.2C if possible to reprogramm this PIC.
I also see 2 problems here, how to change this value and how to change thermometer accuracy which is 0.5C.
 
Can this thermostat be reprogrammed and which programmer to use?
 
 
 
post edited by JohnNovak - 2021/01/06 02:32:34

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#1

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    katela
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    Re: LCD thermostat with PIC16F1947 2021/01/05 10:00:04 (permalink)
    -1 (1)
    Do you have access to the PIC code?

    Free online Microcontroller Tutorials and Projects for Hobbyists and students. From beginners to advanced. Website: www.studentcompanion.co.za
    YouTube Tutorials: https://www.youtube.com/StudentCompanionSA
    #2
    JohnNovak
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    Re: LCD thermostat with PIC16F1947 2021/01/05 10:13:45 (permalink)
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    Hi katela.
     
    Which code do you have in mind?
    Programmable code protection?
    Microcontroller is very complex electronic component i have no any experince with programming.
     
    post edited by JohnNovak - 2021/01/05 10:15:40
    #3
    katela
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    Re: LCD thermostat with PIC16F1947 2021/01/05 10:27:04 (permalink)
    +1 (1)
    You said you wanted to reprogram the PIC and you said you don't have much experience with PIC, so if you have the original code programmed in the PIC, it will be easier for you to modify it rather then starting one from scratch.
    Also remember the resolution of your device could be limited by the temperature sensor used which you did not specify. 

    Free online Microcontroller Tutorials and Projects for Hobbyists and students. From beginners to advanced. Website: www.studentcompanion.co.za
    YouTube Tutorials: https://www.youtube.com/StudentCompanionSA
    #4
    JohnNovak
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    Re: LCD thermostat with PIC16F1947 2021/01/05 10:29:36 (permalink)
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    Yes i wish to modify values only.
    Can PICkit3 programmer be connected to this PIC?
    #5
    JohnNovak
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    Re: LCD thermostat with PIC16F1947 2021/01/05 10:35:19 (permalink)
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    Thermostat use NTC 10K ohm sensor and have IC QTC1806B chip near by NTC.
    Can not find any information about this chip function on thermostat,, unknow chip.
     
    #6
    NKurzman
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    Re: LCD thermostat with PIC16F1947 2021/01/05 11:05:48 (permalink)
    +2 (2)
    If you don’t know how to program, then you can’t change the programming. Certainly if you don’t have the source code that would make it more difficult since you would have to start from scratch.
    You can’t make something more accurate than it is. If the NTC has an accuracy of a half degree say you can’t improve on that.
    You would need to get a better temperature sensor. And if you did you can’t just drop it on the board and expected to work.
    #7
    JohnNovak
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    Re: LCD thermostat with PIC16F1947 2021/01/05 11:09:06 (permalink)
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    NTC resistor is analog component you can not say have 0.5 degree accuracy.
    NTC resistor change resistance with temperature and this value is converted to digital information for PIC,
    or more like to voltage conversion possible too.
    Temperature difference is programmed from 0.5 to 5 C, so why can not be changed to 0.1C step?
    So how this PIC can be read? There is on board connector for i2C programming?
    post edited by JohnNovak - 2021/01/05 11:45:01
    #8
    Mysil
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    Re: LCD thermostat with PIC16F1947 2021/01/05 12:38:54 (permalink)
    +1 (1)
    Hi,
    The programming connector is labeled and organized as ordinary ICSP programming and debugging connector for PIC microcontrollers, so may probably be used to erase and reprogram the microcontroller.
    PICkit 3 may be connected to the programming connector.
    Socket marked with Triangle (arrow) on PICkit 3 shall connect to pin marked Reset. Other pins connect in the sequence thay are placed. 6.th socket on PICkit 3 is not used.
     
    If developers creating the product, knew what they were doing, executable program in the microcontroller is probably protected against reading thru the programming connection.
    So trying to read the program memory is likely to give all zeroes.
    This is to reduce possibility of piracy copying and cloning of the product.
     
    Datasheet for the microcontroller may be downloaded from Microchip website.
    Same for MPLAB X development tools and XC8 compiler.
    PIC16F1947     is a microcontroller with builtin circuits to control LCD display,
    so a PIC microcontroller with that many pins,
    is probably also running display and user interface for a custom LCD display. 
    There is a watch crystal 32.768 kHz on the board to the left of microcontroller,
    so device is probably also running daytime clock and calendar. 
     
    So there is a lot of program in the microcontroller, to take care of all the features.
     
    If you have no previous experience, there will be a long learning curve to reengineer all the features of the device.
    Using Oscilloscope or similar instruments, it is probably possible to figure out what kind of communication there is between microcontroller and the temperature sensor interface.
     
    You may contact the designers, producers, supporters of the product to ask for source program for the microcontroller. I have no opinion whether they will make it available.
     
        Mysil
    #9
    JohnNovak
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    Re: LCD thermostat with PIC16F1947 2021/01/05 12:49:29 (permalink)
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    Thank you very much with a lot of informations.I already contact the manufacturer, Company: Hysen Control Technology Co., Ltd
    This is mass production company they have no time for customer support.
    post edited by JohnNovak - 2021/01/16 10:48:29
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    Antipodean
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    Re: LCD thermostat with PIC16F1947 2021/01/05 13:21:53 (permalink)
    +2 (2)
    JohnNovak
    Hi Mysil.
    Thank you very much with a lot of informations.
    I already contact the manufacturer, Company: Xiamen Hysen Control Technology Co., Ltd
    no any respond from this manufacturer.



    I doubt you will get a response from the manufacturer.
     
    How do you know your device has a hysterisis of 0.5 degrees? If it is anything like my (commercial) home thermostat it is settable only in 0.5 degree steps and probably displays only 0.5 degree increments. it is clear to me that it does internally measure to a smaller increment.
     

    Do not use my alias in your message body when replying, your message will disappear ...

    Alan
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    davea
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    Re: LCD thermostat with PIC16F1947 2021/01/05 15:16:44 (permalink)
    +1 (1)
    which means 1.0C between on and off function which is very low sensitivity for home use.
    I wish to have more sensitive digital thermostat with 0.1C or 0.2C if possible

    they are made that way to keep the compressor from cycling on/off every 5 min
    if it is used for electric heating then that's a different story
    make your own and put it's contacts in series with the W wire and set the original thermostat 
    a few deg's higher
    #12
    NKurzman
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    Re: LCD thermostat with PIC16F1947 2021/01/05 18:16:35 (permalink)
    +2 (2)
    JohnNovak
    NTC resistor is analog component you can not say have 0.5 degree accuracy.
    NTC resistor change resistance with temperature and this value is converted to digital information for PIC,
    or more like to voltage conversion possible too.
    Temperature difference is programmed from 0.5 to 5 C, so why can not be changed to 0.1C step?
    So how this PIC can be read? There is on board connector for i2C programming?



    If you look up the Data sheet for a 10K Thermistor, you will see it has a tolerance.  Just like any resistor.  Could you calibrate a single device?  Sure I guess so.  But you would need a better temperature sensor, and a way to control the Temperature to do it.  An you would then need to write code to use you new calibration.  
     
    The Person the wrote the code, and the company that made it thought 0.5C was fine.  Another issue is the the A/D may not support 0.1C You do not understand. You would need to rewrite the entire program over.  there is no way to just change a setting, UNLESS the original Programmer made it that way.  If you can not write code for PIC CPUs, then you can not do what you want.
    #13
    1and0
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    Re: LCD thermostat with PIC16F1947 2021/01/05 23:02:50 (permalink)
    +1 (1)
    Even if you can read the hex code off the chip, it is no easy task to work with disassembly code even for a professional programmer, let alone by someone who "have no any experience with programming."
     
    #14
    JohnNovak
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    Re: LCD thermostat with PIC16F1947 2021/01/06 02:19:42 (permalink)
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    It is no harm to ask what options are available.And it is not compressor thermostat. Hysteresis can be set by 0.5C step, 0.5, 1.0, 1,5 up to 5.0C Many analog manual dial thermostats with gas sensing have better sensitivity.
    Digital thermostats should be more sensitive otherwise why are on the market?
    post edited by JohnNovak - 2021/01/06 09:15:44
    #15
    JohnNovak
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    Re: LCD thermostat with PIC16F1947 2021/01/06 02:27:35 (permalink)
    +1 (1)
    https://www.elektrobock.cz/en/digital-thermostat/p1744
     
    adjustable hysteresis from 0.1 °C to 6 °C
    #16
    NKurzman
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    Re: LCD thermostat with PIC16F1947 2021/01/06 09:28:30 (permalink)
    +2 (2)
    Perhaps because digital thermostats are cheaper to make?
    You’re basically asking about a marketing choice made by the company you bought the thermostat from. Could they have done what you said, of course. But they didn’t feel it was necessary.
    As far as accuracy is concerned, the more accuracy you want, the more expensive the product is.
    #17
    JohnNovak
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    Re: LCD thermostat with PIC16F1947 2021/01/06 09:45:33 (permalink)
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    To make analog thermostat you neeed a few parts and screws.
    To make digital you need professional programmers and other technology.
    post edited by JohnNovak - 2021/01/06 10:02:21
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    1and0
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    Re: LCD thermostat with PIC16F1947 2021/01/06 10:01:05 (permalink)
    0 (2)
    JohnNovak
    To make analog thermostat you neeed a few parts and screws.
    To make digital you need professional programmers.

    An analog thermostat is cheaper but will cost you more money long term wise because they are not efficient. A digital thermostat on the other hand is more expensive but will save you money long term by making your HVAC system run at the most optimal settings. Also, digital thermostats don’t have mercury; an analog thermostat does.
    #19
    NKurzman
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    Re: LCD thermostat with PIC16F1947 2021/01/06 10:06:28 (permalink)
    +2 (2)
    The cost of the professional programmer that makes a digital thermostat is spread across tens or hundreds of thousands of units.
    Mechanical thermostat are physical things.
    The labor must be put into each one of them. How much handling and machines are required to make a bimetallic strip.

    1and0
    I don’t believe they use mercury in mechanical thermostats anymore, and haven’t for a long time. I retired my 70s vintage one just a few years ago. It had all setbacks for twice the mercury.
    #20
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