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2xDS18b20 GPIO Raspberry PI

Posted: Monday 05 November 2018 11:27
by Ljasteran
Hello!
I conected 2xDS18b20 to 4GPIO Raspberry PI.
pi@raspberrypi:~ $ ls /sys/bus/w1/devices/
28-119995116461 28-3b7882116461 w1_bus_master1
devices
dev.png
dev.png (38.06 KiB) Viewed 2302 times
Help plz. What is wrong? Why is only one DS18b20? And Where is 2nd?

Re: 2xDS18b20 GPIO Raspberry PI

Posted: Monday 05 November 2018 11:35
by emme
directory list 1 device, it is correct Domoticz reflect the directory content

check wirings

Image

Re: 2xDS18b20 GPIO Raspberry PI

Posted: Monday 05 November 2018 11:42
by Ljasteran
pi@raspberrypi:~ $ cat /sys/bus/w1/devices/28-*/w1_slave
5d 01 ff ff 7f ff ff ff 97 : crc=97 YES
5d 01 ff ff 7f ff ff ff 97 t=21812
5c 01 ff ff 7f ff ff ff d4 : crc=d4 YES
5c 01 ff ff 7f ff ff ff d4 t=21750
The wirings are ok.

Re: 2xDS18b20 GPIO Raspberry PI

Posted: Monday 05 November 2018 11:51
by emme
if it does not look for the second device there are few reasons:
1) wirings
2) cable lenght
3) I had more luky once using 5v instead of 3.3v
4) probe damaged
5) module issue (see https://www.raspberrypi.org/forums/view ... p?t=106041 )

make your choice ;)

Re: 2xDS18b20 GPIO Raspberry PI

Posted: Monday 05 November 2018 12:03
by Ljasteran
1 - ds18b20 work (you can see logs on the top of this page)
2 - lenght - 10cm
3 - i try 5. The same result.
4 - See point 1
5 - see point 1

Re: 2xDS18b20 GPIO Raspberry PI

Posted: Monday 05 November 2018 12:05
by Ljasteran
Can it be a bug?

Re: 2xDS18b20 GPIO Raspberry PI

Posted: Monday 05 November 2018 12:21
by rv24531
Try ...
- adjusting your poll timing to a bit longer
- 5v WONT work on the pi, it will at least reboot it. the GPIO's max at 3.3v and more coming in is harmful.

I had several other tips that have worked for me in the past I was going to post, but noticed your cable length is only 4 inches, you certainly shouldn't have any cable length issues there.

Check your private messages, I'm sending you a message.

Richard

Re: 2xDS18b20 GPIO Raspberry PI

Posted: Monday 05 November 2018 12:22
by pmmisiek
Hi,

You can read sensors behind of domoticz so physical connection is OK.

I'm not sure but it looks like domoticz uses 2 last digit of serial number as device ID.
You have 28-119995116461 and 28-3b7882116461 so domoticz shows it as one device.

Please try to use another one ds18b20 - probably it will have different SN :)

BR

Re: 2xDS18b20 GPIO Raspberry PI

Posted: Monday 05 November 2018 18:05
by Ljasteran
pmmisiek, you're right.
I tried another ds18b20. and it is fine.
Thx. I think it is bug, i will write it at "Bugs and Problems".