Solenoid altering One Wire Temp Sensor reading when sharing ground

Hi-

Firstly, thank you to everyone on this forum. As a tinkerer without a degrees in electrical engineering, I would not have as many small successes without the generous folks here.

My question is this:

I am triggering a 40v Solenoid with an Arduino Mega via a FQP30N06L MOSFET. I am monitoring the temperature of this solenoid with a DS18B20 one wire digital temp sensor. It worked as expected when I quickly tested to see if the EMF from the solenoid would affect the temp sensor, which it did not. Now that I have the components in a circuit (and sharing a ground) when the solenoid is active the temp sensor spits out a -196. With my limited electrical knowledge I'm thinking that there must be a voltage drop across the sensor when the solenoid is active. Something that could probably be solved with a capacitor?

I'd love to be able to read the temp when the solenoid is active. Anyone have any insight on how i might be able to do it?

Many Thanks

Hi,
How is this all wired? Where is Ground..

I would suggest using shielded twisted pair wire to the sensor, with the shield as the ground connection. Then run with the sensor moveable and check it things work in different locations.

You might need to use a sensor like THIS and add a braided shield over it.

DISCLAIMER: Mentioned stuff from my own shop...

Yes, and pay attention to where you make your ground connections. Rule of thumb -- connect all grounds to the same point. There are exceptions to this rule, but it's wise to learn the rules before you break the rules. So, best to follow the rule of thumb ;D

Hi, There are some suggestions on the subject here:

http://arduino-info.wikispaces.com/Arduino-Project-Planning-Electrical