Multiple Thermistors

Using Arduino General Electronics
#1

Hi, I'm using an arduino to measure the temperatures on my barbecue smoker. I have two thermistors where one measure the food temp and one measures the grill temp.

I initially thought I could do this just by implementing two voltage dividers and taking a reading off of each. What I did not consider though was that the thermistors and their cables are fully metallic and if they touch one another then they short one another out and in that case the current just takes the path of least resistance and my voltages get messed up. Can anyone offer up any advice?

#2

They can share a common ground with each other and with the smoker enclosure if they are used as the "bottom resistor" in the [u]voltage dividers[/u].

...I'm assuming that the "wires" are shielded (electrically and thermally)? Some kind of temperature probe designed for high temperatures?

#3

Attaching a few more details…

thermistor.png

Untitled.png

#4

You asked the same question yesterday in project guidance.

Starting several threads on the same topic is frowned upon.

#5

I sincerely apologize. I couldn't view the post I made yesterday under that thread and had assumed it did not go through - hence this duplicate.

#6

You need to rearrange the configuration of your circuit so that both the braids are at ground potential.

Your photo shows that the cable is terminated in a jack plug, the braid will be connected to the sleeve of the jack, and there will be an inner insulated wire connected to the tip of the jack.

Re-wire your circuit so that both braids connect to your Arduino GND terminal, then connect the inner conductors to analogue inputs, together with your resistors. Connect the other end of the resistors to the +5V.

#7

Thanks JohnLincoln. You're correct the braided cable is connected to the base of the jack plug. I also rearranged as suggested and I think it's going to work. Really appreciate the help.

#8