CODEWITHSUNDEEP
raspberry-pi
Templog Log
Templog Log

Reputation: 415

Interfacing ds18b20 with raspberry pi

i have a raspberry pi connected with two ds18b20 temperature sensor. -sensor1 is fixed on the outside of my garage (distance 20m from raspberry pi) -sensor2 is just connected in a breadboard near the raspberry pi. Everything is working well.

I decided to add sensor3 located outside and from 20m from the raspberry pi.

Now when i type : cd /sys/bus/w1/devices

if find this: c0-40a000061005 c2-246056869800 c2-247056869000 d0-008000001000 w1_bus_master1

instead of : 28-..... 28-..... 28-.....

each sensor ref should be start with 28-.....

what is happening with my sensors? If unplugged the sensor1, then everything is well

if i unplug the sensor3 and let only sensor1 and sensor2 everything is well.

Which modification do we have to do when sensor are located far from the raspberry pi?

thank you

Upvotes: 0

Views: 301

Answers (1)

user8882551
user8882551

Reputation:

That means that the 3rd sensor doesn't have a 4.7kOhm or 10kOhm resistor between VCC and the OUT wire (black/red one if you have 4wire DS18B20). Just connect that resistor and it will work , I had the same problem . I spent weeks to find such an easy solution. And if you get the same code after you connected the resistor , that means you didn't connected it properly.Hope will help you

Upvotes: 0

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