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Topic: [3/Love-o-meter] it seems TMP36 doesn't work (volts: 0.00 ; degrees: -50.00) (Read 50071 times) previous topic - next topic

mech_1794

Hello,

i have a problem with the temperature sensor aswell. In my case it seems to work properly when it starts but as soon as touch it, the temperature jumps to unrealsitic values.

Here is an example:

Sensor Value: 146, Volts: 0.71, degrees C: 21.29
Sensor Value: 147, Volts: 0.72, degrees C: 21.78
Sensor Value: 147, Volts: 0.72, degrees C: 21.78
Sensor Value: 147, Volts: 0.72, degrees C: 21.78
Sensor Value: 147, Volts: 0.72, degrees C: 21.78
Sensor Value: 146, Volts: 0.71, degrees C: 21.29
Sensor Value: 148, Volts: 0.72, degrees C: 22.27
Sensor Value: 157, Volts: 0.77, degrees C: 26.66
Sensor Value: 182, Volts: 0.89, degrees C: 38.87
Sensor Value: 228, Volts: 1.11, degrees C: 61.33
Sensor Value: 228, Volts: 1.11, degrees C: 61.33
Sensor Value: 229, Volts: 1.12, degrees C: 61.82
Sensor Value: 228, Volts: 1.11, degrees C: 61.33
Sensor Value: 228, Volts: 1.11, degrees C: 61.33
Sensor Value: 228, Volts: 1.11, degrees C: 61.33
Sensor Value: 228, Volts: 1.11, degrees C: 61.33
Sensor Value: 229, Volts: 1.12, degrees C: 61.82
Sensor Value: 230, Volts: 1.12, degrees C: 62.30
Sensor Value: 229, Volts: 1.12, degrees C: 61.82
Sensor Value: 229, Volts: 1.12, degrees C: 61.82



Is the sensor defect? I checked the wires and changed the analog pins but nothing helped. I am wondering what is going wrong since everthing looks fine until i try to measure some changes in temperature. The code is correct because the sensor values fits to the other data, but its value itself behaves unrealistic...



deterr

Hi,

I have the exact same thing. When you start all is normal, but as soon as you touch the sensor it goes up to the unrealistic high values and won't come down again. When you unplug the Arduino and plug it in again, the sensor returns the correct value again and it all starts over again..

Sensor value: 147, Volts: 0.72, Degrees C: 21.78
Sensor value: 146, Volts: 0.71, Degrees C: 21.29
Sensor value: 147, Volts: 0.72, Degrees C: 21.78
Sensor value: 147, Volts: 0.72, Degrees C: 21.78
Sensor value: 147, Volts: 0.72, Degrees C: 21.78
Sensor value: 146, Volts: 0.71, Degrees C: 21.29
Sensor value: 146, Volts: 0.71, Degrees C: 21.29
Sensor value: 146, Volts: 0.71, Degrees C: 21.29
Sensor value: 146, Volts: 0.71, Degrees C: 21.29
Sensor value: 146, Volts: 0.71, Degrees C: 21.29
Sensor value: 146, Volts: 0.71, Degrees C: 21.29
Sensor value: 149, Volts: 0.73, Degrees C: 22.75
Sensor value: 172, Volts: 0.84, Degrees C: 33.98
Sensor value: 208, Volts: 1.02, Degrees C: 51.56
Sensor value: 208, Volts: 1.02, Degrees C: 51.56
Sensor value: 201, Volts: 0.98, Degrees C: 48.14
Sensor value: 201, Volts: 0.98, Degrees C: 48.14
Sensor value: 201, Volts: 0.98, Degrees C: 48.14
Sensor value: 200, Volts: 0.98, Degrees C: 47.66
Sensor value: 201, Volts: 0.98, Degrees C: 48.14
Sensor value: 200, Volts: 0.98, Degrees C: 47.66
Sensor value: 200, Volts: 0.98, Degrees C: 47.66
Sensor value: 200, Volts: 0.98, Degrees C: 47.66
Sensor value: 199, Volts: 0.97, Degrees C: 47.17
Sensor value: 200, Volts: 0.98, Degrees C: 47.66
Sensor value: 200, Volts: 0.98, Degrees C: 47.66
Sensor value: 200, Volts: 0.98, Degrees C: 47.66
Sensor value: 199, Volts: 0.97, Degrees C: 47.17
Sensor value: 199, Volts: 0.97, Degrees C: 47.17
Sensor value: 198, Volts: 0.97, Degrees C: 46.68
Sensor value: 198, Volts: 0.97, Degrees C: 46.68
Sensor value: 199, Volts: 0.97, Degrees C: 47.17
Sensor value: 199, Volts: 0.97, Degrees C: 47.17
Sensor value: 199, Volts: 0.97, Degrees C: 47.17
Sensor value: 199, Volts: 0.97, Degrees C: 47.17


CzarCW

I've had the same problem as mech_1794 and deterr. If I set my baselineTemp to something much higher, say 70 C, then the temperature sensor works fine (5-10 degree increases in temperature in the monitor when I touch the sensor, and then back down when I remove my hand) but none of the LEDs get activated.

Alternatively, if I set the system to run and touch the TMP36 so that it spikes up and registers temperatures around 70 C, and THEN pull out the LEDs one by one, I see the temperature sensor drop back down 10-20 degrees at a time until it's back in the normal range.

Could there by an ungrounded signal or something causing some interference? Would another resistor connected somehow to the temperature sensor pull down any stray voltage?

CzarCW

I switched the spot where by ground wire was connected (along the same ground rail on the breadboard), and it seems to have fixed the problem.

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