The pagers have now been programmed to shut down when their batteries reach a certain voltage (right now, about 3v). A test was conducted to find their battery life. The average battery life was found to be about 18.5 hours. All the data from the experiment can be found in the link below.
http://spreadsheets.google.com/ccc?key=0AmGN0bxAc29ydDdhSzBBMzhyejFPOXFidWJSSUNCWGc&hl=en
Hi, can you also provide me the code you used for this? I will need to adapt the scaling you used to detect the 3v threshold in the production version. Also, I wonder if the scaling or threshold will be the same across all units, or should there be a safety margin. — Ted.
Comment by tedherman — January 15, 2010 @ 6:16 pm
Here is the current version of PuckToRadioC.nc being used for the pagers. This version has also been modified so that the radio is on for one fourth of the time, for sake of experiment. I believe this is the only file Eric modified for the battery threshold, but if you need any more code, please say so.
http://docs.google.com/Doc?docid=0AWGN0bxAc29yZDdqZG5zd18xNGZtcmQ5ZzI&hl=en
Comment by gscranton — January 18, 2010 @ 11:54 am
I have also graphed battery reading verses time for the pagers in this experiment, which can be found below.
graph:
http://docs.google.com/leaf?id=0B2GN0bxAc29yNWNiYTQ3OGItMDRhMC00YWEzLTg4ZTYtMTc4YTIyZDQyYzc2&hl=en
data (in milliseconds and battery reading from mote where 4095 corresponds to 3.9v):
http://spreadsheets.google.com/ccc?key=0AmGN0bxAc29ydGU5anhFRVBxdVNGZHZhekdYWkNWUFE&hl=en
Comment by gscranton — January 19, 2010 @ 6:33 pm
Here is the graph for the second battery experiment. In this experiment, the radio was turned on 1/4 of the time (as opposed to the first experiment in which the radio was on all the time). This time the average battery life was 89.15 hours. This is nearly five times as long as the average battery life in the first experiment (18.51 hours). When viewing the graph, it should be noted that pager 244 was started late in the experiment.
graph:
http://docs.google.com/leaf?id=0B2GN0bxAc29yNDkyZjlhOTYtODVhOC00ODc2LWFiYWYtNDY2YTE4ZTQyYTBi&hl=en
data (time in milliseconds and battery reading from mote where 4095 corresponds to 3.9v):
http://spreadsheets.google.com/ccc?key=0AmGN0bxAc29ydDJQUnladXlGeWZCODZreE1lOWotbWc&hl=en
Comment by gscranton — January 26, 2010 @ 6:53 pm
We didn’t include the PuckToRadioApp.nc code, so here it is:
http://docs.google.com/View?id=dgpd4k5z_5cv77fftw
Comment by gthomas — February 10, 2010 @ 5:39 pm