Today's Message Index:
----------------------
1. 01:04 AM - Re: Re: Electronic Dead Reckoning Distance Calculator (Peter Mather)
2. 06:11 AM - Re: Re: Electronic Dead Reckoning Distance Calculator (Robert L. Nuckolls, III)
3. 06:25 AM - Re: PIC Microchip (Robert L. Nuckolls, III)
4. 06:29 AM - Re: SD-8 Z-13/Z-25 practical setup (Robert L. Nuckolls, III)
5. 06:36 AM - Re: planning (Robert L. Nuckolls, III)
6. 06:39 AM - Re: Electronic Dead Reckoning Distance Calculator (user9253)
7. 06:50 AM - Re: SD-8 Z-13/Z-25 practical setup (cccbuntin)
8. 12:14 PM - Re: Re: Electronic Dead Reckoning Distance Calculator (Robert L. Nuckolls, III)
9. 06:27 PM - fuses vs. breakers "aging"? (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: Electronic Dead Reckoning Distance Calculator |
Unless you need very fast program response look at www.picaxe.co.uk. The
chips are available worldwide.
These are pic chips pre-programmed with a basic interpreter and need nothing
more than two resistors and a serial cable to connect to a PC and program.
The software for the PC is completely free.
The support on the forum www.picaxeforum.co.uk is fantastic and the chips
have i2c, pwm, etc. capability all available in the interpreter
I can and do use PICs directly programmed in C /assembler using various
programmers but for quick prototyping and many applications the picaxe can
not be bettered
best regards
Peter
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
Sent: Tuesday, January 12, 2010 3:22 AM
Subject: Re: AeroElectric-List: Re: Electronic Dead Reckoning Distance
Calculator
> <nuckolls.bob@aeroelectric.com>
>
> At 09:47 AM 1/11/2010, you wrote:
> <fran4sew@banyanol.com>
>
> Bob,
> Thanks for your comments. I am really proud of this project, but did not
> expect many replies because GPS has made dead reckoning obsolete. You and
> another friend suggested using a PIC micro-controller. Unfortunately I
> know very little about them. I understand that a programmer is required.
> It was fun learning how to program the CD74HC4059 counter-divider.
> Learning how to program a PIC micro-controller should be fun too.
>
>
> There's a ton of pic development systems out there
> for under $100, dozens for under $50. You might
> think about subscribing to Nuts and Volts magazine
>
> http://www.nutsvolts.com/
>
> Their advertisers include a number of hobbyist PIC
> systems to get started with. The one we use here is
> only $29 and comes with an exceedingly capable editor,
> assembler package. I think it's the PicKit II. You can
> go the assembler route (I think there's only 35 instructions
> to learn how to use) or the Tiny Basic round offered in
> the Basic Stamp series systems . . . and others.
>
> http://www.parallax.com/
>
> http://www.parallax.com/Resources/GettingStarted/tabid/270/Default.aspx
>
> There are programmers listed on eBay from $15 to over $200. Does anyone
> have a suggestion on which one to buy?
>
> This one is $100 but probably your best bet to get
> up and running quickly in Tiny Basic or Assembler
>
> http://tinyurl.com/yfxgka4
>
> See also:
>
> http://www.mstracey.btinternet.co.uk/pictutorial/picmain.htm
>
> http://tutor.al-williams.com/pic-intro.html
>
> http://www.hobbyprojects.com/microcontroller_tutorials.html
>
>
> I want to build a capacitance to voltage converter for a fuel gauge like
> this:http://www.rstengineering.com/kitplanes/KP0007/KPsch.jpg
> Can a PIC micro-controller replace much of that circuit?
>
> Oh my, yes. I've been halted on a program to do just that.
> The program manager ran out of money. It might come back
> in the spring . . .
>
> The philosophy I'm using alternately charges the
> tank capacitance through a large value resistor
> and discharges it with a transistor. The time it takes
> to charge the capacitor from zero to some reference
> value is measured by the uP. Every other charge/discharge
> cycle, a 100 pf reference capacitor is switched across the
> tank line and the time to charge total capacitances is
> measured.
>
> By having a reference capacitor, calculation of tank
> + wiring capacitance is a simple ratio that wipes out
> errors in charging current or comparator trip voltages.
>
> System accuracy is dependent only on stability of
> the reference capacitor and timing accuracy of the uP
> (crystal controlled).
>
> I can't offer you anything more than that right
> now but I can assure you it's well within the capability of
> the PICs to do the timing, operating the capacitor
> switch and calculating a PWM output value that
> represents % of tank contents. What's more, the
> total parts count is VERY low.
>
> Bob . . .
>
>
>
Message 2
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| Subject: | Re: Electronic Dead Reckoning Distance Calculator |
At 03:01 AM 1/12/2010, you wrote:
>
>Unless you need very fast program response look at www.picaxe.co.uk.
>The chips are available worldwide.
>
><snip>
>
>I can and do use PICs directly programmed in C /assembler using
>various programmers but for quick prototyping and many applications
>the picaxe can not be bettered . . .
OH yeah, forgot about that offering. Yes, it's
one exceedingly versatile application of a
PIC product.
I would encourage any readers of this List
who have an interest in circuit development
for rudimentary tasks to stick their toe in
the software water.
Micro-controllers have become jelly-bean parts.
They're produced and sold for literally pennies.
Yet with creative programming, they accomplish
tasks that we could not do with a quart jar full
of resistors, capacitors and transistors 30 years
ago.
The majority of new product development for the
'Connection is uC based. One good example is the
AEC9024
http://www.aeroelectric.com/Catalog/AEC/9024/
where one set of hardware can perform 4 or more
functions . . . with a parts count that is a tiny
fraction of what it used to take for any one
function built of discrete components.
My grandson will get his feet wet with those
pesky resistors, capacitors and things . . . they're
not going away. They're just getting so small that
you assemble them under an illuminated magnifier.
We'll even build some vacuum tube stuff. While
the idea of considering programmable devices might
have been lesson 19 in the curriculum 10 years ago,
it's been moved up to lesson 10. They really do make
the designer's job SOOOooooo much easier.
Bob . . .
Message 3
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| Subject: | Re: PIC Microchip |
>
>The PIC is know as a "bit banging" chips because it has a number of special
>registers of 8 bits (larger ones in later chips) in which each bit of the 8
>bit byte must be set correctly or it simply will not work properly. If you
>find this kind of detail tedious - a different chip might be a better
>choice.
I would encourage anyone to wade into the register configuration
devices first crack out of the bag. These registers have been with
us since day-one so the concepts are not new, only the capabilities
have grown.
But they are CRITICAL to low cost versatility. For example,
the lowly PIC12F683 has but 8 pins, 2 of which are used up
for Vdd and Ground. This leaves 6 pins which can be digital
i/o, up to 4 channels of 10-bid a/d, PWM outout, edge detecting
interrupt, etc . . . all configured by what bits get put into
configuration registers at programming time. The critters
sell for under a dollar in production quantities.
I don't personally program these yet but I'm going to have
to jump in if I'm going to have anything to hand off to my
grandsons. I cut my teeth on 6500/6800 devices in killobuck
development systems 30 years ago . . . that's when a dinosaur
called the Kaypro II running two 5" floppies under CP/M was
the $low$ workhorse of choice!
Bob . . .
Message 4
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| Subject: | Re: SD-8 Z-13/Z-25 practical setup |
I am trying to figure out if that is a typo or not? I am trying to
figure out if it's worthwhile for me to do this upgrade/mod? Seems
like several people have had issues with this Z-25 setup. If it is
just for a cold startup, I'm not too worried about having that
update. Chances are the battery will have (noticed I said chances)
enough juice to excite the sd-8 without it having to be self
exciting, especially in the way I plan to have it wired.
It was developed to meet a "worry" posted by someone
here on the list . . . it's not likely to be a big
asset. I'd leave it off.
Right now, I have a three position switch setup that is labeled off
-- stby alt (for the SD-8 ) -- ess pwr. If I go to ess pwr, the SD-8
is also on. As of now, I plan on flying around with the switch in
stby pwr, and moving it to ess pwr in the event my main alt fails (to
run what's on the ess pwr and have the stby pwr).
You've combined some switch functions? Keep in mind
that the Z-figures were crafted for failure tolerance
where one goal was to eliminate single points of failure
for multiple systems. Bundling multiple functions into
one switch may make that switch critical.
>From my understanding of this (of flying around with switch in stby
pwr with Z-13 diagram), it will be "energized" and ready if the 60
amp alt fails. It will be ready because the 60 amp alt is producing
more volts than the sd-8, so the sd-8 is just sitting there, excited,
ready to help when the 60 amp alt drops off line. I will know the 60
amp alt fails from the "main volts warn" light from the LR-3, in
which case I will reach down and move the switch to ess bus, allowing
only the ess bus to be powered and allowing the sd-8 to charge the
system (battery/essential bus). Do I have this correct?
No. Leave it off until needed.
I'm working on a set of check-lists for the various Z-figures.
I'll try to that published pretty soon.
Bob . . .
Message 5
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>So, I guess the jumper is what causes the run-on, and whatever I do
>I don't want it in there. I don't already have a separate contactor,
>so the way I understand it my options are; 1) use Z-22 with a relay,
>2) just use a push button rated for 30 amps and no relay.
Yes.
>Can you explain why run-on is a problem if it only lasts a couple seconds?
The design goal for engagement solenoids with
integral contactors is to effect immediate retraction
of the pinion gear when the starter button is
released. There ARE over-run clutches in the starter
gearing that prevents the engine from back-driving
the starter. These are VERY important . . .
For a small starter to be efficient, the armature
is highly geared down to crank the engine at 150
to 300 rpm. when the engine starts, it's suddenly
running at 4x that speed. Were it not for over-run
clutches, this would immediately spin the armature
up to 4x it's operating speed and probably throw
windings, commutator bars, or strip gear teeth.
The run-on phenomenon simply exercises the over-run
mechanism and increases pinion wear for reasons that
do not add value . . . and would not happen except
for an unintended consequence of using the solenoid/
contactor in a manner contrary to original design
goals.
Bob . . .
Message 6
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| Subject: | Re: Electronic Dead Reckoning Distance Calculator |
To Peter, Bob, Ken, Ed,
I know that I can build that capacitance-to-voltage-converter fuel-gauge circuit
designed by Jim Weir using discreet parts that do not cost very much. Using
a PIC microcontroller will cost more in both time and money to purchase the
programmer and to learn how to use it. On the other hand, new technology is
exciting and it will be fun to learn a new skill that can be used for future projects.
Thanks for your suggestions and advice.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=281163#281163
Message 7
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| Subject: | Re: SD-8 Z-13/Z-25 practical setup |
Thank you for your input/reply Bob. Dave :)
--------
Building RV-8
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=281166#281166
Message 8
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| Subject: | Re: Electronic Dead Reckoning Distance Calculator |
At 08:38 AM 1/12/2010, you wrote:
>
>To Peter, Bob, Ken, Ed,
> I know that I can build that capacitance-to-voltage-converter
> fuel-gauge circuit designed by Jim Weir using discreet parts that
> do not cost very much. Using a PIC microcontroller will cost more
> in both time and money to purchase the programmer and to learn how
> to use it. On the other hand, new technology is exciting and it
> will be fun to learn a new skill that can be used for future
> projects. Thanks for your suggestions and advice.
Certainly going the discrete component route has some
educational value . . . as I mentioned, I have plans
for my grandsons to sling a little solder over some
vacuum tubes. I've looked at the schematic in Jim's
article. It's not clear to me that it even works.
There are two oscillators . . . U101A and U101C
who's frequency is set by hysteresis (resistor network
on the minus terminal) and the RC time constant of
network on the plus terminal.
The frequency of the lower oscillator is fixed.
The frequency of the upper oscillator is affected
by the 360 pF variable which I presume is tank
+ wiring capacitance. The output of both oscillators
is fed to positive peak following integrators and
then applied to a differential amplifier and finally
to a gain stage U102B. Offset and gain potentiometers
are provided in the DC gain stages.
It appears that the circuit depends on a DIFFERENCE
in relative duty cycle of the two oscillators. While
they differ from each other in frequency, their duty
cycles will be close to 50% irrespective of frequency.
The stages at U101B and U101D are not frequency
discriminators. I'd like to enlist the assistance
of other electron-herders on the list to confirm
or correct my dissection of this circuit's functionality.
If you're up to the task for conducting the experiment,
you might consider this schematic:
http://aeroelectric.com/Pictures/Schematics/Fuel_Capacitance_Meter.pdf
This circuit was crafted to generate a variable
DUTY CYCLE as tank sensor capacitance changes.
Like any analog circuit, calibration stability
is subject to the sum total of effect contributed
by every nearly every component in the system.
This circuit was never built but it was analyzed
for component effects on the system error budget.
It's possible to build a practical fuel gage but
falls short of the best we know how to do. This
is why I move off to the processor-based design
I described earlier . . . parts count and effects
of those parts on calibration and drift are a
TINY fraction of the analog.
Let's see if anyone else on the List can confirm
that the Kitplanes article fuel gage can be expected
to meet design goals.
Bob . . .
>Joe
>
>--------
>Joe Gores
>
>
>Read this topic online here:
>
>http://forums.matronics.com/viewtopic.php?p=281163#281163
>
>
Bob . . .
////
(o o)
===========o00o=(_)=o00o========
< Go ahead, make my day . . . >
< show me where I'm wrong. >
================================
Message 9
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| Subject: | fuses vs. breakers "aging"? |
>
>This seems to contradict my learning/memory but after 71 years,
>either may be suspect. When asked, I had always advised that
>fuses did 'not' suffer from memory whereas breakers did 'age'.
>Can you point me in a direction to clarify my thoughts?
Sure.
If you put a brand new breaker and brand new fuse
on the shelf for 20 years and then test them, you
wouldn't see a measurable shift in fuse performance
and you might see a tiny shift in the breaker. (This
presumes, of course, that you could "test" the fuse
before you stored it away!.)
The breaker is an electro-mechanical device and
therefore subject to some effects of age . . . but
I've never found an old breaker from my junk box
(some more than 40 years old!) that was not still
suited to task after being in service, removed and
stored. Fuses have no moving parts and as long as
they're not stored in a horribly corrosive environment,
there's nothing to "age".
However, there ARE effects of service stress that may
affect fuses and breakers differently . . .
Have you ever pulled a glass cartridge fuse and
seen a "sag" in the fusible element running down
the center? A fuse is a one-time, melting (fusing)
thing. When operated in a manner that bangs the
edge of its heating characteristics, the element
can become 'plastic' and change shape without going
all the way. Any change in shape during a transient
event ALWAYS works to reduce the I(squared)T energy
needed to trip the fuse . . . i.e. it drifts downward
with repeated service stresses over time.
This is why the fuse engineering catalogs suggest
that a fuse be operated at no more than 75% of
rating . . . less is even better if the system
whacks the fuse hard or often with transient
events. A typical 'fast' fuse is the glass cartridge
ACG series from Bussmann:
http://aeroelectric.com/Mfgr_Data/Fuses_and_Current_Limiters/Bussman/AGC_Specs.pdf
Note on page 2 of the spec sheet that a 1A fuse will
carry 1A forever at room temperature but takes 200
seconds max at 2A. Suppose you whacked it with 5A
for say 10 milliseconds every time you turned on a
devise that draws only 1/2A but has some fat capacitors
across the input. Notice on page 2 of the spec that
on average, a 5A load will open the fuse in 50 milliseconds.
Suppose your electro-whizzie hits the fuse at 5 a for
10 milliseconds. Way too small to open it for one
hit or perhaps even dozens of hits. But each hit can
cause the fuse element to change shape slightly to
the point where it may ultimately fail to carry rated load
any more.
It's hard to do this on purpose and it's very rare
accidently but it has happened. This is why you
can buy fuses with "slow blow" or current limiters
with "long blow" characteristics.
This is a phenomenon that does not plague breakers
especially those neat little double break minatures
that we're all so fond of.
So when one speaks of the aging of these components,
you have to differentiate between effects of time
under normal conditions or the effects of stress
under transient overload.
Bob . . .
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