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Re: IBM Wearable PC!

hurley bryan wrote:

> Right, so I just want to know what exactly I need to do to put a switch in
> there, possibly with diodes so I can have one battery, then plug in
> another one, then switch, for a millisecond or two they will both be
> plugged in, and in that small time, I don't want to overload anything,
> backwards, or however. I look to do it with relays maybe in the future off
> the parallel port or something nice that monitors the battery status then
> changes as needed, with multiples hooked up at once, with many switches.

Well, you can just use a good sized capacitor (in parallel with your battery
connection) to give you a few seconds to change batteries.  And since the battery
your replacing with is higher voltage then the one that was there you don't have the
problem of putting reverse current through your new battery.  This is infact
something Steve Mann uses in one of his WearComp specs
(http://www.wearcam.org/wearhow/)

Also, if you use a good DC-DC converter between your power supply and your
motherboard they generally have builtin capacitances inside (like the isolated Datel
models) and can have the power temporarilly removed (<1s) without further
modification.

-Paul