TMP36 adc values varying wildly with RedBoard and arduino

Sensors Environmental
1

I’m trying to read reliable data from TMP36 with my Redboard.

I’ve carefully followed instructions for both the 5V and the 3.3V (with Vref)

https://learn.adafruit.com/tmp36-temper … emp-sensor

I used the layout and code listed on adafruit.

In addition, Ive also grounded the extra analog pins for good measure.

Ive also implemented a 30ms to 60ms delay between reads, try get rid of any residuals.

My ADC readings are pretty consistent for about 60% of the time. the remaining would be a massive grouping of either low or high values for 1 - 3 seconds, about 60 off from expected baseline. I dont mind the measurement tolerances of 5, but the erratic data screws up my control loop.

Any thoughts on how to improve ADC readings?

I’ve also tried to get readings with a voltage divider and my adc readings vary about ± 3, which is rather worrisome.

Do I have a bad ADC on my Redboard?

Thanks in advance.

2

The odds of the ADC being bad are really low but you might have a bad pin. Have you tried a different analog in on your RedBoard to see if you have the same results?

Another thing you might try is putting a 0.1uF cap across VCC and GND right at the TMP36, that would help stabilize voltage to the sensor and that can help with fluctuations in it’s output.