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Metalviolator001
Apprentece
5 Posts |
 Posted - Mar 22 2009 : 12:02:28 AM
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| Hello. i am building a LED temperature thermometer and i do not really know how to read the LEDS. cause i know we need 10, but know do u know that it will read the room temperature? can u help me out? |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Mar 22 2009 : 10:31:25 AM
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| The more LEDs that are lit, the higher the temperature. If you want actual numbers you will have to calibrate it using a thermometer. |
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Metalviolator001
Apprentece
5 Posts |
Posted - Mar 22 2009 : 11:52:21 AM
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| ok cool, but what is the scale of the LEDS cause i dont know how high 10 LEDS will read. i am saying that because i want to check it wit the thermometer and check it just by looking at the LEDS. |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Mar 31 2009 : 10:07:47 AM
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| The scale depends on how you calibrate it. |
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Metalviolator001
Apprentece
5 Posts |
Posted - Apr 07 2009 : 1:18:21 PM
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| ok thanks. i have another problem. i already built the circuit however when i turn on the circuit my LEDS do not come on. do you know why that is? i want to know why because i want to add stuff to the LED themperature thermometer. please reply as soon as you can. |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Apr 11 2009 : 11:09:56 AM
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Have you double and triple checked your wiring?
Have you attempted the calibration procedure on the page? |
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Metalviolator001
Apprentece
5 Posts |
Posted - Apr 21 2009 : 12:56:18 PM
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| sorry i didnt respond sooner. i had other school work that i needed to do. yes i double checked the circuit and it still doesnt work. i will take the whole circuit apart and start from scratch. i have a few questions. what are the purpose of C1, C2, R6, and R4. it does not explain the purpose y they incorporated those components in this circuit. i am asking, because if the circuit doesnt really need it i dont really want to use it. please let me know as soon as u can. thanks |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Apr 26 2009 : 10:48:20 AM
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| The datasheet of U2 will explain those components. C1 decouples and filters U1, smoothing it's output a bit. |
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Metalviolator001
Apprentece
5 Posts |
Posted - Apr 26 2009 : 9:40:12 PM
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| o ok thanks i will look for the data sheet. i re-built the circuit. i found what my problem was. i placed the LED's in the wrong position. the thing now is that when i turn on the circuit, all the led's come on at the same time. i do not think that is right. i caibrated R5 and R7. i even tried to calibrate R1, but i cant caibrate it to 3 times the value of R3. how will i be able to do that if R1 is a trim pot and it only goes to 1k ohm maximum? let me know as soon as u can thanks. |
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LED temperature Thermometer
