for many applications, all you really need is a comparator that signals to powerd to do a graceful shutdown appropriately. wearcomp5 had full battery monitoring (battery level), but i found that i seldom actually used it. all i really wanted in the end was to save myself from fsck. steve Prof. Steve Mann University of Toronto > In line with my previous message: > > It would be fairly simple to put together a small A/D converter which could > monitor battery voltage. It could be connected to the normally unused printer > port available on most PC/104 CPU modules. Modern A/D converter chips are > small and need only a few passive components. A software driver would be > quite simple and could be made to run periodically to monitor the battery and > alert the user when it crosses a specific threshold. > > I would think that an 8-bit device (small and low power) would be sufficient. > That would provide 256 scaled voltages (e.g., from 12 v to 10 v). > > The ADC0844CCN 8-bit A/D converter is a CMOS device (low power) which contains > full microprocessor interface circuitry on a 20-pin DIP. It even contains a > multiplexer for measuring four different voltages. Cost of this chip is about > $6.00 US. > > Such a device would also be useful in tracking long-term battery performance. > The driver would only have to keep a history of the voltages. > > I will look into this and come up with a simple design if there is interest. > > Regards, > Arne
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