Jamie put the logger components in a new box (orange, on top) that is even smaller than the old box (silver, on bottom). Right now he is running a program on the Android phone to record the temperature to make sure that the electronics will not overheat in their new closer quarters.
The graph shows the temperature recorded by a Nexus S phone, using software that we wrote to log its battery temperature. (The PC either has no non-CPU temperature sensors or they are not visible to the OS.) The phone battery temperature is typically a few degrees higher than the ambient temperature. While the temperature did not fully stabilize during the 2.5 hour test, it appeared to be leveling off with a likely asymptote at around low-to-mid 40 degrees Celsius. This is good news, since the most sensitive component in the box, the lithium polymer battery, should be kept under 60C. The logger PC itself uses a solid state disk, and should thus be able to exceed 70C. It was a chilly day in the shop, so during actual use the external temperature will usually be higher and the sun will be shining on the box, so we will repeat the test outdoors on a warmer and sunnier day.
This was also the first test in which we used a single small battery to power the PC, the radio link, and the N2K network for an extended time period. Extrapolating from the amount of charge used, we expect to be able to run these devices for at least 6 hours on a battery charge.Return to News