ShaunTheQuietGamer
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Waterproof DS18B20 isn't showing up in /sys/bus/w1/devices

Thu Jun 13, 2019 1:44 am

using this tutorial -- https://www.jeremymorgan.com/tutorials/ ... pberry-pi/ -- i have setup the tempurature sensor as it says to do, i have already enabled 1-wire and rebooted,

Code: Select all

pi@raspberrypi:~ $ sudo modprobe w1-gpio
pi@raspberrypi:~ $ sudo modprobe w1-therm
pi@raspberrypi:~ $ cd /sys/bus/w1/devices
pi@raspberrypi:/sys/bus/w1/devices $ ls -la
total 0
drwxr-xr-x 2 root root 0 Jun 12 18:30 .
drwxr-xr-x 4 root root 0 Jun 12 18:30 ..
lrwxrwxrwx 1 root root 0 Jun 12 18:30 w1_bus_master1 -> ../../../devices/w1_bus_master1
pi@raspberrypi:/sys/bus/w1/devices $ 
and loaded the kernel modules, but the folder that should show there doesn't.

pcmanbob
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Re: Waterproof DS18B20 isn't showing up in /sys/bus/w1/devices

Thu Jun 13, 2019 10:55 am

I might help if you post a picture of you pi and the wiring to the sensor just so we can check you have it connected correctly, as a non functioning sensor is often down to incorrect wiring.

just upload your picture to imgur.com and post a link here.

If everything is connected correctly then it would suggest you have a faulty sensor, but I would not worry about that until we have had a chance to check your wiring.
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rpdom
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Re: Waterproof DS18B20 isn't showing up in /sys/bus/w1/devices

Thu Jun 13, 2019 11:32 am

Further to the good advice that pcmanbob has provided, you should note that the "sudo modprobe" commands are not required if the correct entry is set in config.txt as mentioned in the (somewhat out of date) instructions. The w1-gpio module should be loaded at boot time and the w1-therm module will be loaded on detection of the probes.
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ShaunTheQuietGamer
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Re: Waterproof DS18B20 isn't showing up in /sys/bus/w1/devices

Thu Jun 13, 2019 8:10 pm

I should also clarify, I have more than one, and I switched it out, and that one started heating up so much that it burned me, with the red wire in power, black wire as ground, and yellow as data. Swapping red and black, it still heated up, but not as much, but it didn't show any data.

pcmanbob
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Re: Waterproof DS18B20 isn't showing up in /sys/bus/w1/devices

Thu Jun 13, 2019 8:13 pm

A sensor heating up is an indication of incorrect connection to the pi, which is why I asked to to post a picture.

Were did you get your sensors from , there have been a number being sold on some cheap on line sites that are rejects or have incorrect wiring.
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PhatFil
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Re: Waterproof DS18B20 isn't showing up in /sys/bus/w1/devices

Thu Jun 13, 2019 8:35 pm

pcmanbob wrote:
Thu Jun 13, 2019 8:13 pm
A sensor heating up is an indication of incorrect connection to the pi, which is why I asked to to post a picture.

Were did you get your sensors from , there have been a number being sold on some cheap on line sites that are rejects or have incorrect wiring.
indeed i bought a set of 10x with ss caps and 1m leads and spent an afternoon soldering 1 after another to a 2.5mm 4 pole jack and resistor without a single successful connection. thankfully a spare transistor style packaged ds18b20 was at hand that i could use to validate my circuits.. Very Frustrating... Whats worse i didnt chuck the 3-4x i didnt test and have bought more (working) since at closer to $2 each rather than the $1 'bargains' and pf course they have gotten mixed up ;)

pcmanbob
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Re: Waterproof DS18B20 isn't showing up in /sys/bus/w1/devices

Thu Jun 13, 2019 8:44 pm

The ones I got worked for about 3 months or so then just kept going off line , very frustrating when your projects are already installed.

I ended up dismantling the waterproof ones and installing my own DS18B20 sensors in the the casings reusing the wiring as well so far so good.
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ShaunTheQuietGamer
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Re: Waterproof DS18B20 isn't showing up in /sys/bus/w1/devices

Fri Jun 14, 2019 2:59 am

pcmanbob wrote: A sensor heating up is an indication of incorrect connection to the pi, which is why I asked to to post a picture.

Were did you get your sensors from , there have been a number being sold on some cheap on line sites that are rejects or have incorrect wiring.
I wasn't the one that purchased them, it is actually a project for class, my teacher got them.
https://drive.google.com/file/d/10640Fl ... sp=sharing
https://drive.google.com/file/d/107dWuc ... sp=sharing
https://drive.google.com/file/d/105NJi7 ... sp=sharing

pcmanbob
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Re: Waterproof DS18B20 isn't showing up in /sys/bus/w1/devices

Fri Jun 14, 2019 7:39 am

So the wiring on your bread board looks ok , but are you sure you have the ribbon cable the right way round between the pi and the breadboard ?

if you put a meter on the 3.3v rail and the ground do you get 3.3v ?
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ShaunTheQuietGamer
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Re: Waterproof DS18B20 isn't showing up in /sys/bus/w1/devices

Fri Jun 14, 2019 6:23 pm

pcmanbob wrote:
Fri Jun 14, 2019 7:39 am
So the wiring on your bread board looks ok , but are you sure you have the ribbon cable the right way round between the pi and the breadboard ?

if you put a meter on the 3.3v rail and the ground do you get 3.3v ?
I don't have one.

pcmanbob
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Re: Waterproof DS18B20 isn't showing up in /sys/bus/w1/devices

Fri Jun 14, 2019 10:31 pm

You can do the same test with a red LED and a 470 ohm resistor connected in series connected between 3.3v and ground, now you want the connected the right way round for the test , so look for the flat edge on the LED the leg on that side goes to ground.

If you are still unsure try the LED both ways round.
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