NewRPL announciator question

[Claudio L.]

I'll add a little more hard data for those who care:

Originally I had code displaying the voltage. Made no sense other than cause anxiety... I calibrated it with my unit, but other members of the team reported their unit had different calibration, so there's that: each calc reports slightly different voltage. Voltage also doesn't tell you much because what really matters is the voltage drop while under load. And that load also is different from calc to calc, especially if you have a an SD card. The critical operation is a program that calculates something and writes results to an SD card: CPU kicks in the turbo while the SD card is writing to flash. But power consumption on SD cards varies wildly too, so does the voltage drop.

So I ignored the voltage and went with crash: calc crashed at about 4.5V when under load, so the blinking indicator I calibrated slightly above around 4.7V. The solid indicator if I recall correctly is calibrated around 4.9V. Think that if you are using alkalines you should be around 6V with 4 new batteries. NiMH are 1.2V but the brands I tested typically have around 1.3V to 1.37V when charged and the voltage drop isn't that significant.

I understand people might prefer to custom-calibrate the indicator but really, it will apply to only one calc, with one type of batteries, and you'd have to sit down with your multimeter to read the voltages with the calc under load, then try several SD cards to make sure... it's a pain, not worth anybody's time I think.