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1WPi+ does not see any sensor

1069 Views - Created 31/07/2017

31/07/2017

Posted by:
srgimee

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Hi, on a pi3 with kernel 4.9.40-v7+, I am unable to see any 1w device. I have two DS18B20 and one relay (https://store.brewpi.com/temperature-control/solid-state-relays-ssr/brewpi-onewire-ssr-expansion-board). 

Test made with a single DS18B20 connected directly via RJ12 plug. Solderings of the RJ connecter have been tested ok with ohmmeter.

No sensor is seen:

owdir
/bus.0
/uncached
/settings
/system
/statistics
/structure

However the pi seems to communicate with the board:

pi@pi3-sdr:~ $ i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- 18 -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

i2cdump -y 1 0x18
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX 08    XXXXXXXXXXXXXXX?
10: XX XX XX XX XX XX XX XX XX XX XX XX XX XX 08 XX    XXXXXXXXXXXXXX?X
20: XX XX XX XX XX XX XX XX XX XX XX XX XX 08 XX XX    XXXXXXXXXXXXX?XX
30: XX XX XX XX XX XX XX XX XX XX XX XX 08 XX XX XX    XXXXXXXXXXXX?XXX
40: XX XX XX XX XX XX XX XX XX XX XX 08 XX XX XX XX    XXXXXXXXXXX?XXXX
50: XX XX XX XX XX XX XX XX XX XX 08 XX XX XX XX XX    XXXXXXXXXX?XXXXX
60: XX XX XX XX XX XX XX XX XX 08 XX XX XX XX XX XX    XXXXXXXXX?XXXXXX
70: XX XX XX XX XX XX XX XX e9 XX XX XX XX XX XX XX    XXXXXXXX?XXXXXXX
80: XX XX XX XX XX XX XX e8 XX XX XX XX XX XX XX XX    XXXXXXX?XXXXXXXX
90: XX XX XX XX XX XX e9 XX XX XX XX XX XX XX XX XX    XXXXXX?XXXXXXXXX
a0: XX XX XX XX XX e8 XX XX XX XX XX XX XX XX XX XX    XXXXX?XXXXXXXXXX
b0: XX XX XX XX e1 XX XX XX XX XX XX XX XX XX XX XX    XXXX?XXXXXXXXXXX
c0: XX XX XX e8 XX XX XX XX XX XX XX XX XX XX XX XX    XXX?XXXXXXXXXXXX
d0: XX XX 01 XX XX XX XX XX XX XX XX XX XX XX XX XX    XX?XXXXXXXXXXXXX
e0: XX 01 XX XX XX XX XX XX XX XX XX XX XX XX XX XX    X?XXXXXXXXXXXXXX
f0: 18 XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    ?XXXXXXXXXXXXXXX

 

 

Ideas welcome!

 

31/07/2017

Posted by:
andrew

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Location:
United Kingdom

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Hi

Have you gone through all of the steps in our OWFS tutorial?  There is a python script at the end of the tutorial which will show a list of the devices that are connected to the 1 Wire Pi.

It may be worth trying to connect the DS18B20 to the solder pads instead of the RJ12 just to make sure there isn't a problem with the connector or wiring.  We have a tutorial for connecting a DS18S20https://www.abelectronics.co.uk/kb/article/9/1-wire-with-ds18s20-digital-thermometer which is the same pinout as the DS18B20.

AB Electronics UK Tech Support

01/08/2017

Posted by:
srgimee

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Thanks Andrew. You are right, it was a problem of wiring. I contacted the seller of the DS18B20 (https://store.brewpi.com/featured/triclamp-onewire-temperature-sensor) and asked for a wiring diagram of the sensor, and it turned out the pinout of their RJ plug did not match yours.

I fixed the cabling and it is now working great. Thanks for the help!

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