Bug Filed on 12-13-2015: Adding and Removing GPIO OP / DS18B20


1. Is this related to iOS or the online dashboard?


2. Please describe the issue you are experiencing in as much detail so we can quickly resolve.

  • Removing digital generic output takes time and needed reboot and a few dashboard resets.

  • In general adding basic GPIO button takes time and several sessions or resets to complete

  • Removing any of the DS18B20 temperature sensors is locked out as an option on all three Pi. On Raspberry Pi B C0 there is a ? half constructed DS18B20 giving a huge fixed negative junk reading.
    I will try a re flash of Pi etc in a day or so.

  • Have seen several double or multiple simultaneous ‘session timeout’ messages (Chrome) Is there a timeout per Pi ?

~ Andrew



I’m playing with two DS18B20 sensors. One is working and another one it is showing huge negative values.
Overall about dashboard:

  • the removal of one graph/sensor/widget take a lot of time in most of the cases it remains in the dashboard
  • I have a graph widget and I cannot remove it(the remove button is not available). the graph show an abnormal negative values
    About graph (I’m talking about graphs which are working).
  • we should can select Celsius
    -we should can select graph resolution and time
    Wright know, the graphs are running on default values, values not available to user config.

Thank you


We’ll take a look at the slowness/reboot/dashboard reset that’s needed to remove a digital generic output. @svazir

Will also look at adding GPIO buttons. @svazir

A negative reading generally means the one-wire sensor is not configured properly, no? (We have a task to create a ‘sensor disconnected’ error when a large negative reading appears - good idea?)

The dashboard will automatically add a one-wire sensor if it’s connected, that may be why there is initially no option to remove it…as a user, you should have the option to remove any of your sensors, we’ll re-evaluate this.

The session time-out is set for one hour. I assume you saw the time-out within one hour? Did you see the time-out while you were still moving around in the dashboard? In which case that’s a bug and we’ll need to fix.



Hey Bogdan,

For the DS18B20, a negative number generally means it’s not configured properly, did you check the wiring? The dashboard also automatically detects the DS18B20 one-wire sensor, so you should not need to go through the add process for it.

Yes, we will change the ability to remove the one-wire sensors…

Yes, we’ll add the ability to select the type of measurement (Fahrenheit / Celsius)…

We’re working on a ‘History Graph’ that will enable you to select graph resolution and time.

What values were you looking to configure, can you give example??

Thanks for this!


  • The big negative number was on an old Pi so not to worry
  • The method of adding a DS18B20 is not clear and that is probably my problem
  • I know that with WebIOPi there is a simple single DS18B20 but I have yet to test a more advanced level when you place more than one in parallel to see if it ‘auto detects’ more than one DS18B20. This is possible with WebIOPi but you have to find the unique device serial number and add this into the system first. Do you know if the intention is to have multi DS18B20 on ONE ‘one wire buss’ or if this is possible. Again a short video would show me where I am banging head against my Pi… If just one DS18B20 was always the intention then that is fine…

Temperature scale:

  • I see that the word Farenheight comes up some times. Initially the DS18B20 seemed to toggle over time between Deg C and Deg F so I thought it would be easy and simpler for you to just have one OR the other in the setup process (recommend this)
  • The graph auto ranges reliably. But I can not make both the minimum and the maximum woras expected. E.g. say temerature averages 92 to 97 Deg F then setting minimum to 90 and maxina to 100 should give me a nicre detailed resolution. I get some times the 90 degreee with a maxima about 190.

More soon
~ Andrew


@svazir @akaranfilian Need to test:

  1. auto-range of graphs.
  2. Farenheight mispelling.
  3. adding multiple one-wire sensor


Simple video would be a great start.
Only speaking for me but I am focused almost entirely on the GPIO header so showing how this (switchboard and control room) works behind the scenes would be great too…
~ Andrew


FYI guys we tested adding multiple DS18B20 and we were able to get correct temp. reading from both which were automatically discovered and connected to GPIO Pin 4. Videos coming


Thanks will give this a spin.
Next nag… ‘Deg_C’ and or a ‘Deg_F’ option some place in the setup of the DS18B20 ?
~ Andrew


Yep, in our roadmap to allow for the dashboard to toggle between metric or U.S. Standard, depending on user preference.



We’re still working on allowing the removed of a 1-wire sensor. Resolving this for the other bugs reported.

Work around for deleting DS18B20 1-wire temp sensor