Sky-High Analog Readings with Datashield Connected

[jmichael]

Can anyone think of the reason a TMP36 temperature sensor would give me a reading ~6x higher when attached to 5V, GND, and an analog pin through the Adafruit pre-assembled Datalogger shield than when attached to an Arduino alone?

(When I've got more time I'll resubmit this question with more information, if need be. Right now I'm just hoping this shot-in-the-dark plea has an obvious explanation to someone out there.)

**Edit for more information** I did actually mistake a transistor for a temperature sensor the first time I started the whole thing up, unbelievably. Did I fry the on-shield voltage regulator?

My circuit looks sound, but to list the other components involved, I've got: a 4-digit 7-segment LED display, a push button hooked up to a digital pin, and a power switch for a 9V battery. All work fine. The RTC and SD card reader/writer on the data logger work great.

I think that if there is something wrong with the analog pins on the data logger shield, it's a result of my initial mistake, but in that case I'd like to know what happened.

Thanks for any guesses or help at all,
-Jason

[adafruit_support_bill]

Can anyone think of the reason a TMP36 temperature sensor would give me a reading ~6x higher when attached to 5V, GND, and an analog pin through the Adafruit pre-assembled Datalogger shield than when attached to an Arduino alone?

The analog pins on the data logger shield are simply pass-through's of the Arduino analog pins. If you are getting different results it is most likely because you have the sensor connected differently.

If you post photos of the front and back of the shield, we can check your assembly.

[Franklin97355]

If you are still having trouble I would recommend taking everything off but the temp sensor and try it on the same pins on both the Arduino and the shield to see what you get. Post the output you get from the program in both cases.

[jmichael]

Thank you all for responding. I finally figured out what was wrong. I had forgotten to connect 3V to Aref for the sensor

D'oh.

Thanks again!