Jeremy

"I'll see you on the Dark Side Of The Moon" - Pink Floyd

Covert Ops
68k Hacks General
Macs Liberated:18
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If you are using system 7.1, you might try using a little 14k Desk Accessory called Battery that has a thermometer style readout of battery level, but I don't think it gives time remaining.

If you are using something earlier than 7.1, I throw up my hands (although you could always try that System 7.1 Desk Accessory if you are feeling a bit adventurous).

May your battery charge never dwindle,

g4from128k

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If you are using System 7.5, you might try using the Battery Monitor control strip (it is 26k and the Control Strip control panel is 43k). Uhh, wait a minute, you said you were booting from a floppy, so 7.5 is probably too fat. Let me start again

If you are using system 7.1, you might try using a little 14k Desk Accessory called Battery that has a thermometer style readout of battery level, but I don't think it gives time remaining.

If you are using something earlier than 7.1, I throw up my hands (although you could always try that System 7.1 Desk Accessory if you are feeling a bit adventurous).

May your battery charge never dwindle,

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software! software! we don' need no steenkeeng software!

be a man and hack an analog test meter into the that laptop' palmrest sonny! Galvanometers ROCK!

jt ?. .

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Edited by - g4from128k on 29 May 2002 06:00:32

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Yehhh!!! And if you use a zener diode in the meter circuit you can create a nice offset voltage and much expanded sensitivity for a little battery meter. That way the little galvanometer will read out say between 10V and 14V as the needle moves from 0 to full-scale.

You can sometimes find little galvanometers in old audio equipment at garage sales (used as signal strength meters before LED bar graphs appeared). I've seen little ones as small as 3/4" in diameter. Note that galvanometers do draw current from the battery (typically between 50 microamps and 1 milliamp) so the little meter will drain the battery if left plugged in several weeks or months straight. But if you recharge your PB every month or so, it should be OK.

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WOWSERS! sounds like rex and i have been joined by another crazy old coot! or have you been blessed with an early onset of seni . . . err . . . eccentricity!?!

how would you hook up a relay and switch circuit to make sure the galvanometer only drew power when the laptop screen was enabled or the button switch was pressed?

or would the circuitry draw more than the galvanometer overall?

i used to help out on electronics projects (heathkits . RC Planes etc.) because i was much better with my hands and tools than the electron pushers, but i never really learned much more than rule of thumb level stuff on the theoretical/design end.

are you another fan of the tinaja questing guru?

jt ™. .

RE relays and circuits. Yah, I suspect that a relay would draw more power than the galvanometer (the mechnical forces in a good galvanometer are very small compared to those in a switching relay, so the electrical power required to actuate a relay is higher than that required by the galvanometer) But, I can think of multiple schemes (some of dubious practicality) that do not draw much power:

1) reed switch'n magnet design: if you install a normally-closed reed switch on the PB's base and a magnet on the lid, then opening the lid pulls the magnet away from the switch and closes the circuit. The advantage of the reed switch is that it draws no power, being activated by the proximity of the magnet.

2) phototransistor-on-screen: glueing a phototransistor to the corner of the screen would provide a natural on-off switch tied to the backlight being on or not (of course it might be a challenge to tweak so that ambient light doesn't leak in a trigger the device.) You could also just leave the phototransistor exposed to ambient light (triggered by opening the lid). Either way, you would also have to factor in the forward voltage drop of the transistor in selecting zener diodes or calibrating the meter.

3) locking relay design: I belive that some specially designed relays have bistable properties (one short pulse of power closes the contact, a second short pulse of power opens the contact). But I suspect that these relays are really big and clucky. Another disadvantage is that you have to remember to turn-off the circuit each time.

4) microswitch: a normally-closed microswitch embedded in the base of the PB. Opening the lid would unclick the switch, closing the circuit and turning on the galvanometer.

5) don't worry be happy: if you find a nice galvanometer (say, one that draws less than 500 microamps) then you could just leave it plugged all the time. It might take the circuit more than 2000 hours (12 weeks) to drain a fully charged battery. Moreover, if you use a zener or other fixed voltage drop, you are assured to not draining the battery to 0-volts (this can sometimes destroy a battery pack when the stronger cells in the pack force current through the weaker ones. The result is that the weaker cells actually get forced into a reverse polarity condition that is hard to recover from).

I am sure that other creative members of the 68kMLA can arive at some rube goldberg inventions for this project

g4from128k

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LOL, you got me pegged!! I'm both a crazy old coot and blessed with accelerating dementia (wish I had a PDS slot so I could upgrade me brain to an '040).

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HAR!™ with three of us old codgers hanging with the webkiddes we need to have a Grizzled Veterans of Antiquated OS Wars lodge hall with a PDP 8 on the lawn and 8" disk drives half buried in the dirt around it or some crap like that! (and a cash bar with a round CRT TV and a crappy pool table!)

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I am sure that other creative members of the 68kMLA can arive at some rube goldberg inventions for this project

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i'd actually suggested this seriously to somebody who wanted to hack a multiple led guage readout into their PB over at fritter. with a big@$$ (but low profile) upgraded IDE drive in a 190, you could cut away the plastic support and palmrest over the drive and have all kinds of room for a BIG plexi window for the analog needle readout and some custom circuitry. i like your idea of refining the readout scale/sensitivity, if you designed a really snappy lookin' PCB for the bottom of the well and printed just a narrow arc for the readout scale leaving the balance of the PCB/components exposed under the glazing it'd be a VERY retro-cool hack! (to the old farts around here like rex anyway! )

it'd probably work on a SCSI PB too, but availability of decent drives is a problem, are there low profile 2.5" SCSI drives afailable at all?

jt ™. .

p.s. try to come up with a snappy acronym for our sigs, guys! smart@$$ suggestions from the webkidde brigade would probably be considered!

Edited by - Trash80toG-4 on 29 May 2002 11:07:17

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