Go Down

Topic: Bizarre reading from a single DS18B20 (Read 1 time) previous topic - next topic


I'm new to the Arduino and 1-wire sensors, but I had the sensor working perfectly with my Uno.  I then built a dedicated shield with connectors and resistor for the 1-wire and now can't get it to work.  When the shield is not connected, ie no resistor or 5V connection, I get a reading of 32 Fahrenheit (or 0 centigrade when I change the code to display centigrade).  When the shield is installed but no sensor is connected, I get -196.60 (or -127 centigrade).  When I connect the sensor, I get the same readings.  How do I know if the sensor is damaged and not working??  As I said, it was working and was intermittently not working - now not at all.  I'm using it in parasitic mode.

Thanks for your help!!


You could first try it in normal mode; -127 means the sensor is not found. The cause can be in the sensor itself, the wiring (connection , capacity, pull up resistor etc) or in your sketch. Did you modify it recently? Post your code if you want us have a look.

This  http://milesburton.com/index.php/Dallas_Temperature_Control_Library contains a device count function. might be helpful

Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)


The sensor was - it thanks!  Although each wire checked out, when I desoldered and then resoldered the sensor, it worked.

Thanks for your help!


Go Up

Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

via Egeo 16
Torino, 10131