multiple temperature sensors

I want to read about 30 temperature sensors and data-log the readings. this will be almost exclusively data-logging,

I have been playing around with the LM34 and the accuracy and speed seem to be acceptable.

any suggestions on how best to add another 29 sensors ?

I would like to be able to scan all 30 in about one minute or less.

Analog sensors require an analog input (which you have a limited number of) and require calibration. Digital sensors are much easier to use. If you use the DS18B20 digital sensors you can daisy-chain multiple sensors on a single 1-wire bus. I don't know that you'd get all thirty sensors on a single bus, but you'd certainly get them on a few buses. How far apart do the sensors need to be? The 1-wire bus isn't designed to operate over long distances.

dave-in-nj: any suggestions on how best to add another 29 sensors ?

Humorously: One at a time?

Seriously: Shift registers. Nevermind. Analog sensors.


I am not tied to any sensor, digital or analog. I have a few LM34's so I started working with them. distance from the board will not exceed about 50 feet.

In looking it seems there might be A/D chips that would read the sensors then feed the data back via serial

or analog multiplexers that would allow me to send each of the A/I's a signal and change those inputs and let the on-board ADC do the work.

or, digital sensors.

my temperature span is about 0°F to about 110°F

I would be very happy to get 1/10th of a degree resolution.

as for calibration, I am hoping to put them all in a box and hope the temperature will stabilize and then move the box to the out side and let it stabilze as that freezing level.

thanks for the links.

suggestions are welcome !

One option: