I believe there are at least 3 ezChronos owners around and since now I am looking into a 'HEQ firmware' for those models (and not necessarily just for my own watch) there might be a few questions involved:



- who has one (or more) ?



- have you tried programming a different firmware inside (for instance the supplied data-logger) ?



- do you have other temperature-related 'hardware' (similar to the mini-fridge that we have discussed in other threads) ?



- are you willing to do watch accuracy-measurements (or have you done so already - not necessary on the ezChronos but on any quartz watch - for instance with the video method) ?



There are still a number of problems to be solved but it seems that in the absence of a special (dedicated) hardware device to 'calibrate' each watch, the simplest approach would be to assume that the raw quartz from inside has a temperature response that can be well described with something like a*t^2 + b*t + c = 0 , but until we see otherwise we should assume that the a/b/c coefficients above are specific to each quartz and we should each try to measure those with decent accuracy - which IMHO would be feasible by having 3 timing measurements of around 2 weeks each at 3 'temperature points' - and since it is very unlikely that all of us will be able to keep the watch within 0.1 C for a full 2 weeks it is acceptable to keep it in a range of plus or minus 1-2C but with temperature-logging in effect for the interval (which will also help us in calibrating the results against the actual temperature that is seen by the watch). The 3 'target temperatures' should be something like 'fridge temperature', 'room temperature' and 'warm temperature'.



We should also discuss if it might be OK for this thread to become the 'home' for the 'ezChronos HEQ' or if we will just use some other approach.