tmp36 wrong when they are used on a perforated plate?

Other Hardware Sensors
1

hello
I started a project "weather stations'' with 2 Arduinos, two Ethernet Shields, 6 (3 for 1 arduino) tmp36 temperature sensor, and the Max / MSP software to display the sensor data with the OSC protocol.

I managed to run the communication between sensors, Arduino, Ethernet scheild and Max / msp with the help of this forum and using allimentation 3.3 volt, a ceramic capasiteur put the sensor in parallel a resistance of 750 owm has analogue output on a breadboard. However, when I put everything on a plate perforated, data values ??were stable but completely erroneous, without any change in temperature even if the environmental conditions changing.

I retest only 3 tmp36 and putting the arduino 3.3v power and change the code, reading is always the same and I do not understand the behavior of the sensor.

why tmp36 values ??are wrong when they are used on a perforated plate?

before any welding, I had very good values ??using 5v power with 3 sensor and arduino. I had to change a 3.3volt when I add the ethernet scheild to have good data on the breadboard

Note that I have two identical systhème on the same patch Max / Msp, two serial ports, but different because two different places where I have to take the temperature

Do you have any ideas?

thank you in advance for your help

emmanuelle

2

Do you have a 0.1 ?F bypass capacitor on the input ? And you need a resistor if you driving capacitive load

3

do you mean the analog input or power supply the input ? and the resistor, where do I place it exactly?
thank you for your answer!

4

Here you something to go by.

tmp36.PNG

5

I just did that ... I think I inversser power and grounding ... but I resolder the new sensors correctly and still I do not really have the same data on the breadboard ... around 10-12 ° C when it welded and 17-18 ° C on the breadboard ... and this is the temperature on the breadboard that is good

I have no idea to be wrong!

thank you for your help

Emmanuelle

6

The reading on these are based on the ADC and the ADC uses the voltage as reference which can change from board to board.

You need to read the voltage on the AVCC pins and see if there the same on both and are you hooking them up the same. 100nF to gnd and a pullup to VCC