Hi all
Although a similar subject to a current thread, this is a different issue, so I thought I’d start a new one.
I’ve currently got a TMP36 connected to an Imp, uploading data to Xively. It only took an hour to get going from scratch, such was the excellent guidance/tutorials by forum members here
My current regime is to take the temperature every minute. and store the last 10 minutes of readings, ie 10 readings stored in an array at any one time. New reading comes in and pushes the oldest one out. Every 5 minutes, the 10 current readings are averaged and sent to Xively. This helps with a bit of graph smoothing. It’s not a super-accurate sensor, so you lose nothing there.
I’ve been seeing some spurious readings, eg…
Note the drop at 2pm.
I added code to the functions so that if the Imp is reporting a drop of 2 degrees or more in a 5 minute period, the raw values are logged to my own server. This is what we see for the 2pm reading…
[2013-12-05 13:57:39] log.INFO: a:1:{s:9:"logstring";s:86:",9.067677,9.067677,9.067677,9.067677,9.067677,9.14824,8.98711,-49.9987,9.14824,8.98711";} [] []
Now, clearly the -49 degree reading is completely wrong! Has anyone noticed such issues with the TMP36 module, or, perhaps more pertinently, any issues with the ADC on the Imp producing random readings like this?
Any thoughts/speculation would be appreciated!
Cheers