1-Wire Temperature Sensor - DS18B20 - on Omega2

[Lazar Demin]

As @Robert-Wenzel mentioned, b151 fixes the one-wire issue

Here's a new article on using One-Wire with the Omega2: https://docs.onion.io/omega2-docs/communicating-with-1w-devices.html

Happy hacking!

[Vaclav VESELY]

@Lazar-Demin perfect. All works correctly now. I appreciate the speed of Onion team and the power of the community.

[Joris Mulliez]

Thanks @Lazar-Demin for the correction.

But it seems not to work on my omega 2+.

I just upgrade my firmware, and try to follow the tutorial you mentioned.
But I can't see my DS18B20... I see only slaves like : "00-800000000000" it seems "fake".

First question : the sensor must be plugged into the board before or after omega started ?

And here is my output when I just install the "master" one-wire, without plug any sensor :

# insmod w1-gpio-custom bus0=0,19,0
[  100.959174] Custom GPIO-based W1 driver version 0.1.1
root@Omega-0000:/# [  102.882550] w1_master_driver w1_bus_master1: w1_search: max_slave_count 64 reached, will continue next search.
[  150.298561] w1_master_driver w1_bus_master1: Family 0 for 00.800000000000.8c is not registered
[  209.629280] w1_master_driver w1_bus_master1: Family 0 for 00.400000000000.46 is not registered.
root@Omega-0000:/# cat /sys/devices/w1_bus_master1/w1_master_slaves
00-800000000000
00-400000000000
[  257.010981] w1_master_driver w1_bus_master1: Family 0 for 00.c00000000000.ca is not registered.
root@Omega-0000:/# cat /sys/devices/w1_bus_master1/w1_master_slaves
00-400000000000
00-c00000000000

So there is "ghost" sensors appearing automatically, and If I try to plug my real sensor, I can't see him...

Am I doing something wrong ?

Thanks for your help,

[Costas Costas]

@Joris-Mulliez the ghost ID means you didn't wire the sensor correctly.

[Joris Mulliez]

@Costas-Costas Even if I don't plug anything ?

[Costas Costas]

Yes the 1-Wire just makes up the ghost ID.

[Lazar Demin]

@Joris-Mulliez did you add a pull-up resistor to the data line of your sensor?

[Don DeGregori]

I have the Power Dock. Where is GPIO19? I don't think it is brought out. What other pin could I use for testing the 1-wire DS18B20?

[Kit Bishop]

@Don-DeGregori This is really strange. For the Expansion Dock (see https://docs.onion.io/omega2-docs/expansion-dock.html) GPIO 19 (and GPIO 18) are shown as exposed next to I2C SCL/GPIO 4 but for the Power Dock (see https://docs.onion.io/omega2-docs/power-dock.html) these two same pins are shown as GND

To Onion devs: what gives? I understood that the expansion header on the Expansion Dock and on the Power Dock were supposed to be the same thing for connecting expansion boards. It is more than concerning that the documentation shows that they are different

[Don DeGregori]

This is true. In the docs under 1-wire communication, I see this:
Note that making these connections is very easy if you have a Expansion, Power, or Arduino Dock since they all expose the Omega’s GPIOs.
Maybe we'll see clarification next week.
Also, I can't upgrade to b151 or b152. Still shows b150

This problem of upgrade is cleared

Still Power Dock doesn't expose GPIO19 to use with DS18B20 sensor. What pin should I use instead?

[Costas Costas]

@Don-DeGregori you have to wget the b152 to /tmp and then sysupgrade.

[Akshat Mehra]

This post is deleted!

[Don DeGregori]

@Costas-Costas
OK, I did the wget and I saw the download complete. Now I follow this with sysupgrade command by itself?

[Costas Costas]

@Don-DeGregori the full command (for a 2+) is:

sysupgrade -n /tmp/omega2p-v0.1.9-b152.bin

[Don DeGregori]

@Costas-Costas
Did it before I saw latest post. Left out -n. Any problem?

[Chris Stratton]

-n tells it not to try to backup and restore your customizations

I'm not sure if the current system configuration supports doing that cleanly; if there's any question, doing a factory reset now or otherwise wiping the overlay would have the same effect at this point as having used the -n option in the upgrade.

[Don DeGregori]

@Costas-Costas
I guess what I did before was this only with the latest firmware.
Forgot I should have used sysupdate instead or also.

wget http://repo.onion.io/omega2/images/omega2p-v0.1.5-b135.bin

OK now. See (b152) in on terminal splash.
Thanks all

[Don DeGregori]

@Lazar-Demin
The Power Dock does not expose GPIO19. Which pin would be a substitute?

[Lazar Demin]

@Don-DeGregori they should all work, I've personally tested with 18 & 19 and had no issues!

[Gabriel Ongpauco]

@Don-DeGregori

On the Power Dock, pin 0 works. The other numbered GPIOs on the bottom row should work as well.

Gabe