I'm in the middle of building an automated hydroponic setup , which is going pretty much to plan apart from one small problem.
I have a small sensor board I have built that contains a Dallas 18B20 for sensing water temp , an LDR for measuring light levels , and a DHT 11 for air temp and humidity. This is all uploaded to a cosm stream, and works well for the most part. After fighting to compile the sketch to include the Dallas sensor, things seemed to be working as they should , no erroneous or wild readings - apart from when the grow lights switch off in the evening ( and consequently the LDR resistance drops ) the dallas starts reporting 85 degrees ( which I believe is an error code ).
My question is this : Would the sudden drop in resistance of the LDR be causing some issue with the DS18B20 ? Once it starts reporting "85" that is all you will get out of it. Would a small cap help? ( The Dallas is running off the 5v , not parasite power )
As as newB I'd appreciate some help or explanation of why turning off lights causes the temp sensor to go mental.
EDIT : There is no improvement in the Dallas ( ie still reporting 85 deg ) even after rebooting the Arduino....
Cigarette packet - style circuit drawing:https://picasaweb.google.com/lh/photo/wfOH7TMHpKe3b-tXrDnPKd1Py__ZBgFcthW_L892y6Y?feat=directlink