[arm-allstar] [1.2.1]pcsensor possible issue

David McGough kb4fxc at inttek.net
Sun Nov 9 12:26:22 EST 2014

Hi Joel,

I confirmed the overflow issue that you reported is present in results
from the "Temper1" device as well. I've hacked the changed calculation
into the pcsensor.c code version included with the BBB 1.2.1 release and
confirmed that the overflow is resolved with the "Temper1" sensors.

Also, I changed the correction-factor code ("-a" option) to directly use a 
signed floating-point number (in Celsius), making correction easier.

I didn't add any other changes, for now. Please try this code 
on the "Temper1F" device when you have chance--I'm interested to hear if 
it works properly.

Here is a link to the code: 

On a side note, I noticed that the "Temper1" devices seem to be available 
on ebay, again. The original manufacturer (http://www.pcsensor.com ) told 
me that these were discontinued. So, I'm guessing they are illegal clones.


73, David KB4FXC

On Sat, 8 Nov 2014, David McGough wrote:

> Hi Joel,
> Thanks for finding this info. I've been using the older "Temper1" units.  
> I haven't yet used the "Temper1F" version.  However, I understand from the
> manufacturer that the older sensors are no longer available for sale and
> the Temper1F is the replacement model.
> I've looked over the updated source code, listed below, and noticed that
> it seems to loose some functionality included in the original version--in
> particular the "-n" (allows querying multiple units) and "-a"  
> (correction factor) options seem to be missing. So, a little hacking may 
> be in order, since I'm using these options. I've got several sensors in 
> cabinets monitoring heatsink temps, etc., at different spots.
> We'll plan to include an update in the next release to support the 
> "Temper1F" (and perhaps a few other models now available) correctly.
> Thanks again-
> 73, David KB4FXC
> On Sat, 8 Nov 2014, Joel Jameson wrote:
> > I just hooked up a TEMPer1F device to play around with, and noticed the
> > sensor temp readouts were a tad high.
> > 
> > [root at bbb41187]# pcsensor
> > 2014/11/08 16:03:59 Temperature 492.79F 256.00C
> > 
> > I dug this up on google about this behavior:
> > http://lee.smallbone.com/2014/10/using-temper1f-usb-temperature-probe-on-raspberry-pi/
> > 
> > As my temp outside is close to 0C, that page pointed me to this patch:
> > https://github.com/petechap/usb-thermometer
> > 
> > after making/installing the file, the temp is now correct and lists as:
> > 
> > [root at bbb41187]# pcsensor
> > 2014/11/08 16:05:53 Temperature 31.99F -0.00C
> > 
> > I'm not sure if it's just the unit I have, or if this should be included
> > for the release :) It could be I should move the whole rig and
> > myself south as a workaround...
> > 
> > Cheers,
> > Joel
> > W0KGW
> > 
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