Subject:
|
Re: Battery Status
|
Newsgroups:
|
lugnet.robotics.handyboard
|
Date:
|
Tue, 4 May 1999 03:06:59 GMT
|
Original-From:
|
Duncan Orthner <ORTHNER@IDIRECT.COMspamless>
|
Viewed:
|
1000 times
|
| |
|
|
At 08:48 PM 5/3/99 -0400, Richard Drushel wrote:
> [Duncan Orthner] spake unto the ether:
>
> > At 01:40 PM 5/3/99 -0700, Andre Philippi wrote:
>
> > > 2) Could I use one of the analog ports on the Handy Board to measure • battery
> > > voltage (and therefore calculate capacity left (assuming voltage is
> > > information enough for the calculation)) ?
> >
> > Yes. You could use a voltage divider. You may have to play with the cutoff
> > point a bit, and be aware that nicads experience a rather sharp voltage • drop.
>
> But isn't the supply voltage also the reference for the D/A
> converter? If the reference drifts, the signal through the divider
> leg will also drift?
Umm, yes. But only if the battery is 5volts. Presumably, the voltage
regulator on the HB is being supplied with well over ~6.5 volts (usually a
9.6v battery). Thus the output of your divider could be read via an analog
input until the battery voltage dropped below the cutoff for the regulator.
Actually, a voltage just above the cutout on the regulator would make a
good 'low battery warning' point ie ~6.5 to 7v. The point is that the 'low
battery' point would be reached well before the 5v AD reference began to
drift...or (more likely) the regulator cut out.
Sweet Dreams, Duncan
|
|
Message is in Reply To:
 | | Re: Battery Status
|
| (...) This is usually how it's done. The voltage will drop predictably as the battery discharges. (...) Yes. You could use a voltage divider. You may have to play with the cutoff point a bit, and be aware that nicads experience a rather sharp (...) (25 years ago, 3-May-99, to lugnet.robotics.handyboard)
|
5 Messages in This Thread:
 
 
- Entire Thread on One Page:
- Nested:
All | Brief | Compact | Dots
Linear:
All | Brief | Compact
|
|
|
|
