DS18b20 giving all kinds of readings

hello everyone i am using DS18B20 waterproof temperature sensors in my aquarium. when i initially set them up they worked correctly giving readings of 78.2 78.6 etc i had my arduino shoot craps so i replaced it now that i have rehooked everything back up the sensors are giving me readings of 185f then random 78.1f then random error no device readings. i accidently hooked the 5v to the data line and the data line to the 5v pin do you think i smoked them and need to be replaced. this hook up was only done for a few seconds before i found the mistake and unhooked them. do you think they could be shot in this time frame?

If you believe that the new Arduino is working correctly, the only way to know for sure about a possibly dead DS18B20 is to compare results with a new DS18B20.

Get the newest OneWire library, and use the example that comes with it. It shows the ROM ID and it tells if the checksum is okay. If the checksum is okay, and the temperatures are wrong, then the DS18B20 is somehow internally damaged. https://www.pjrc.com/teensy/td_libs_OneWire.html

thanks for the replies i will try your suggestion peter these things are dirt cheap anymore have some more on the way if nothing else i will have replacements for later use thanks guys