• Registered: 2008-03-05
  • Posts: 6

Topic: Indoor Thermometer

I don't know if this has been suggested before, but it would be nice to have the Chumby be able to give you the room temperture.  Just an added little extra that would enhance the unit further.

  • Duane
  • Duane
  • Blue Octy
  • Offline
  • From: San Diego, CA
  • Registered: 2006-08-24
  • Posts: 8,209

Re: Indoor Thermometer

Two issues: first, the chumby does not have an ambient temperature sensor; and two, if it did, like most sophisticated electronic devices, it produces its own heat, in which case it would be devilishly trick to be measure the ambient temperature accurately.

The way this probably would have to be done is to communicate with some other device that's actually taking the temperature reading.

Duane's Website

3 Reply by wayn3w (edited by wayn3w 2009-03-02 08:00:03)

  • Registered: 2007-11-09
  • Posts: 340

Re: Indoor Thermometer

I had worked on this for a while and stopped due to other life concerns.  I'd be happy to share what I have so that others who may consider it a worthy project can pick up from it

The problem has been to find a USB-based thermometer that is cheap and readily usable in Linux.  The one I found that seemed the most useful and cheapest was this device:

http://www.lascarelectronics.com/temper … logger=365

I wrote a libusb-based application to read the raw values and it seemed to work on Linux.  So the next steps were:

* write a Chumby daemon to get the raw values and store running averages and such; this would also listen for requests from local widgets in order to return the current temp/humdity et al.  I got stuck here because I couldn't quite get libusb and libhid compiling under the chumby tool stream (if anyone would like to do this and get it package up, I'd appreciate it! I know it's doable).

* Work with Lascar to see if they'll provide information, perhaps in exchange for providing official linux support.  A daemon is a daemon is a daemon ... it should be able to work both on the Chumby as well as regular Linux, so it wouldn't be difficult to set up a source forge effort for long-term support.  Without Lascar's support I'm guessing as to how to map raw values to real temperatures. 

It's been educational to pursue this -- if others would like to get involved, please feel free!  In fact, I'll start the ball rolling by writing to Lascar now.   If there are OTHER USB-based temperature readers that would be a better fit (supported under Linux, USB, small form factor) please let me know.

wayn3w

  • Registered: 2008-03-14
  • Posts: 45

Re: Indoor Thermometer

Maybe an answer is the 1-wire weather devices.

There are usb adapters for them and open source drivers.

http://sourceforge.net/projects/oww/

http://www.maxim-ic.com/products/ibutto … irekit.cfm

  • Registered: 2008-10-17
  • Posts: 203

Re: Indoor Thermometer

I have always wanted to control the heat from my chumby, and reading this, there might be a way to do it.

  • Registered: 2007-11-09
  • Posts: 340

Re: Indoor Thermometer

If someone recommend a specific set of hardware, i.e. one specific AAG kit, one specific USB adapter, then I could see working on such project.  It appears to me the hardware alone is over $100 -- is that not so?

wayn3w

7 Reply by gregf (edited by gregf 2009-03-05 08:25:43)

  • Registered: 2008-03-14
  • Posts: 45

Re: Indoor Thermometer

Maxim's DS1921K Thermochron iButton Starter Kit  is $60

http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2820

Or from Hobby Boards the same usb adaptor DS9490R with a sensor board.
Hardware wise a little more diy.
http://www.hobby-boards.com
USB Adapter   $28
1 wire temperature sensor $21.50

Hobby Boards has a lot of info on 1-wire networks.

  • Registered: 2007-11-09
  • Posts: 340

Re: Indoor Thermometer

Two years, several major crises and a job change later, I finished the first version of my Chumby indoor thermometer using the Lascar EL-USB-RT USB Temperature/Humidity Monitor:

Chumby, Front View

Chumby, Rear View

I wrote a daemon using the chumbyhttpd and libhid libraries, which publishes upon demand the temperature and humidity so a widget could could request the values and display them any way it wishes.  All necessary files, including the widget are on the USB drive, so it's easy to install (I wish someone made a USB drive that can you can plug in other USB devices so they could virtually share a port, making this setup then work for a Chumby One).

The El-USB-RT device is fairly accurate and precise, so I recommend it for applications like this.  I cannot recommend any others because, well, each USB thermometer is different so code has to be written to support them; and I personally haven't used any others USB thermometers. 

I mention this now so that if anyone is interested, I can make my code available.  It's open source from widget to daemon, using the open source tools scratchbox, mtasc, swfmill and gcc.

  • Duane
  • Duane
  • Blue Octy
  • Offline
  • From: San Diego, CA
  • Registered: 2006-08-24
  • Posts: 8,209

Re: Indoor Thermometer

Nice work!

I love it when people do stuff like this with their chumbys.

Duane's Website

  • Registered: 2010-08-11
  • Posts: 10

Re: Indoor Thermometer

Can you share your source code, I was thinking about doing the same thing reading a one wire ds1820 connected to an arduino

  • Registered: 2007-11-09
  • Posts: 340

Re: Indoor Thermometer

Sure.  I'll send you e-mail via the forum when the tarball is ready (should be tonight).

  • Registered: 2010-09-29
  • Posts: 1

Re: Indoor Thermometer

wayn3w - nice project! I would also very much like to share your source. I'm working on an EL-USB-RT project too! Thanks in advance!

  • Registered: 2010-10-01
  • Posts: 1

Re: Indoor Thermometer

allen80602 wrote:

wayn3w - nice project! I would also very much like to share your source. I'm working on an EL-USB-RT project too! Thanks in advance!


Please check this.

  • Registered: 2007-11-09
  • Posts: 340

Re: Indoor Thermometer

randolf_carter wrote:
allen80602 wrote:

wayn3w - nice project! I would also very much like to share your source. I'm working on an EL-USB-RT project too! Thanks in advance!


Please check this.

You mean I did all that work for nothing? :-)  At least I can say I wrote mine first

http://www.connact.com/~wayne/temperature.tgz is the tar ball containing everything.  There's a small bug in the debugchumby script, but I'll correct that over the weekend.  It shouldn't stop you from proceeding.

  • From: Colorado
  • Registered: 2007-08-06
  • Posts: 17

Re: Indoor Thermometer

La Crosse Technology's new Weather Direct line of thermometers and hydrometers may be a good solution to getting multiple indoor/outdoor temps to Chumby.  The sensors feed data to La Crosse's website that you can then access via the web, I Also read in one of the reviews on Amazon that the data can be fed to an FTP site.  I just ordered a set of their hardware to start playing with it.

http://www.weatherdirect.com/products.aspx

  • Registered: 2011-07-11
  • Posts: 4

Re: Indoor Thermometer

I would have to agree that this would rather be just an auxiliary addition that would entail much update in terms of hardware.  The reading for heat is not that accurate either as gadgets produce their own heat. And as far as I have experienced, readings are always tad higher, which could be traced to the reading with the gadget's own temperature at work.