Today's Message Index:
----------------------
1. 12:03 AM - Re: Expando Foam and Custom Boxes... (Jim Jewell)
2. 12:41 AM - battery bus directly from battery terminal? (Dan Checkoway)
3. 05:47 AM - Re: Need advice on small connector for avionics (CardinalNSB@aol.com)
4. 06:03 AM - Re: My Fuel Gauge Design (Eric M. Jones)
5. 06:41 AM - Re: Expando Foam and Custom Boxes... (Robert L. Nuckolls, III)
6. 06:52 AM - Re: Re: Need advice on small connector for (Robert L. Nuckolls, III)
7. 06:55 AM - Re: Odyssey PC680 terminal with larger ring (Robert L. Nuckolls, III)
8. 07:03 AM - Re: 10nF mylar cap. (Robert L. Nuckolls, III)
9. 07:05 AM - Re: Odyssey PC680 terminal with larger ring (Robert L. Nuckolls, III)
10. 07:07 AM - Re: Z-11 (Robert L. Nuckolls, III)
11. 09:26 AM - Re: battery bus directly from battery (Robert L. Nuckolls, III)
12. 10:09 AM - Re: Odyssey PC680 terminal with larger ring terminal (HCRV6@aol.com)
13. 10:18 AM - Re: Re: Need advice on small connector for avionics (DHPHKH@aol.com)
14. 10:22 AM - Re: Re: Need advice on small connector for (Larry Bowen)
15. 10:40 AM - Re: RF burns from antenna . . .fact or mythology ? (Robert L. Nuckolls, III)
16. 10:46 AM - My Fuel Gauge Design (j1j2h3@juno.com)
17. 11:50 AM - Re: Cheap blind encoder. (Robert L. Nuckolls, III)
18. 12:08 PM - Fuel gauge design (Eric M. Jones)
19. 03:35 PM - Re: Cheap blind encoder. (Gilles.Thesee)
20. 05:15 PM - PTT - Ground Wire (Duane Bentley)
21. 06:46 PM - Re: Cheap blind encoder. (Don Honabach)
22. 08:15 PM - Re: Cheap blind encoder. (Rino)
23. 08:53 PM - Re: PTT - Ground Wire (Robert L. Nuckolls, III)
24. 10:11 PM - 10nF capacitor (Rob W M Shipley)
Message 1
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| Subject: | Re: Expando Foam and Custom Boxes... |
--> AeroElectric-List message posted by: "Jim Jewell" <jjewell@telus.net>
Hello Don,
How about putting the board inside a baggy or a zip-lock bag before potting
it in the foam. Then if there even came a need to look at the board it might
more easilly reached.
Jim in Kelowna
----- Original Message -----
From: "Don Honabach" <don@pcperfect.com>
Subject: AeroElectric-List: Expando Foam and Custom Boxes...
> --> AeroElectric-List message posted by: "Don Honabach"
<don@pcperfect.com>
>
> I'm in the process of retrofitting my Garmin GPS 195 handheld unit to my
> panel (I love this unit - one of the best I've seen even though it's an
> old one by technology's standards). Because my panel is small (Zodiac
> 601) and the unit's full height will interfere with my layout I've taken
> the GPS apart and looked for ways to mount just the screen and buttons
> to the panel and save the 1.5 inches of 'wasted' built-in antenna space
> which is exactly what I need to get the unit to fit. It does look like
> I'll be able to rig something together for the panel mounting the key
> components of the GPS, but will then have to put the main circuit board
> for the GPS in a box and mount it behind of the panel where I have more
> space options.
>
> I remember seeing an article about if you needed a quick dirty way to
> keep a circuit board secure in a box, you could use the expanding
> insulation foam to secure the circuit board. Obviously, this would make
> working on the board in the future difficult if not impossible, but I
> highly doubt I'll be troubleshooting a high denisty board with 99.9%
> surface mounted components. Also, this would make sure the board was
> protected from the vibrations as well.
>
> Any way, was hoping to get some thoughts on using the expanding foam to
> secure the main PCB in a box - pros or cons...
>
> Thanks!
> Don Honabach
> Tempe, AZ - 601HDS
>
> P.S. If for some reason this doesn't work, I can always just go
> purchase a Garmin GPS Pilot III which will fit very nicely without any
> mods, but that would be the easy way and then I'd end up with a smaller
> GPS screen ;)
>
>
Message 2
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| Subject: | battery bus directly from battery terminal? |
--> AeroElectric-List message posted by: "Dan Checkoway" <dan@rvproject.com>
Bob,
In all of the Z figures the battery bus is supplied power from a wire that
comes off the "always hot" terminal of the battery contactor. In my
particular case, because of where I would like to mount the battery bus fuse
block, I'd like to power the it directly from the battery's (+) terminal in
order to satisfy the "6 inches or less" requirement and still be able to
locate the battery bus fuse block in a reasonable location.
Is this acceptable, wiring directly from the (+) terminal as opposed to from
the contactor's hot terminal?
If so, is there any advantage or disadvantage to using a separate ring
terminal vs. soldering the smaller battery bus wire right into the 2 AWG
ring terminal for the wire to the battery contactor? I figure a separate
ring terminal (and just stack 'em) makes the most sense but figured I'd ask.
Thanks in advance,
)_( Dan
RV-7 N714D
http://www.rvproject.com
Message 3
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| Subject: | Re: Need advice on small connector for avionics |
--> AeroElectric-List message posted by: CardinalNSB@aol.com
I would like to have small connectors between my audio panel and the various
avionics for easy removal of tray and upgrade, or to just pull tray and be
able to work behind the panel. I would appreciate thoughts and places to buy and
brand name or an numbers.
Also, can someone please give me a basic briefing of the pin insertion and
retraction tools, are all Mollinex the same for instance or are there different
sizes.
Thank you Skip Simpson
Message 4
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| Subject: | Re: My Fuel Gauge Design |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>--> AeroElectric-List message posted by: Jerzy Krasinski
krasinski@direcway.com>
>>> 5/29/03, Eric M. Jones" <emjones@charter.net> wrote:
>>>(snip)
>>>Put ten tiny tiny tiny 0805 size PTC thermistors on a flex circuit with a
>>>snipped
Exactly. Thermistors have been used for level sensing for a long time too.
But they only recently were available in tiny 0805 SMD. Some other changes
in technology make this scheme more attractive that previously.
>However, temperature of the liquid is not constant, it can vary between
>say 40C on a hot day in Oklahoma to say -20C on a cold day somewhere
>further North .
Yes. The thermistor I plan to use has a 70C transition. The ones I have in
the prototype are 110C,
so they get hotter than I would like, but they are tiny and as they
say...It's only a prototype....
>To make it more complicated all PTC thermistors that I
>was working with had positive coefficient within relatively narrow
>temperature range, and outside of that range they behaved like standard
>NTC thermistors. ...........
>That would require to select a PTC thermistor with positive coefficient
>temperature range somewhere above the highest possible ambient
>temperature, say above 50C.
The transition temperature is all that's important here. It must be above
any likely fuel temperature. BTW--Gasoline flash point is minus-40C, boiling
point is +40C to 200C more or less.
>runs into normal NTC range, its resistance goes up, the thermal power
>generated in the thermistor goes down, and that power might not be
>sufficient to heat it up to 50 deg even if it is above the liquid.
Yes. That could be. So a parallel resistor in close proximity to the PTC
might be required. Sounds like R&D.
>There is another possible problem. Imagine that it is very hot outside,
>the thermistor is additionally heated by the current, it gets very hot
>until it jumps over the PTC range into the normal NTC range. Now its
>resistance decreases as it gets hotter, which pumps more current into
>it, which makes it hotter and lower resistance, which pumps even more
>current, etc., until it melts.
Yes, however I surmise if it gets THAT hot out. My airplane will melt first.
>Both problems can be solved driving the thermistors from a proper
>current source. However, the second problem might still happen
>producing false reading rather than melt down.
Maybe...
>There is an additional problem of comparing (changing with ambient
>temperature) resistance of the submerged thermistors with also changing
>with the ambient resistance of the thermistors above the surface. It is
>possible that there is a trick which might make it easy, but it seems
>again that interpretation of the results would be the easiest with a
>microcontroller that would sequentially measure resistance of
>thermistors and set the liquid level between the group of thermistors
>with equal (but not constant) resistance, and the first hotter one.
We're going to see. A microprocessor would still be a good addition to any
system.
>Am I missing something? Is there an easy way?
>Jerzy
I think a PTC thermistor system could be the simplest method. It is even
possible to build ONE long monolithic flexible thermistor. How would it
change with fuel level???
BTW--I still have my amazing self-heating pitot tube that calmly maintains a
30C temp. Inside are 30C PTC thermistors. Nothing else.
Thanks for the great input.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
Message 5
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| Subject: | Re: Expando Foam and Custom Boxes... |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:42 PM 6/1/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: "Don Honabach" <don@pcperfect.com>
<snip>
>I remember seeing an article about if you needed a quick dirty way to
>keep a circuit board secure in a box, you could use the expanding
>insulation foam to secure the circuit board. Obviously, this would make
>working on the board in the future difficult if not impossible, but I
>highly doubt I'll be troubleshooting a high denisty board with 99.9%
>surface mounted components. Also, this would make sure the board was
>protected from the vibrations as well.
>
>Any way, was hoping to get some thoughts on using the expanding foam to
>secure the main PCB in a box - pros or cons...
I suggested the foamed-in-place encapsulation for securing
spider-webbed assemblies using techniques described in
http://www.aeroelectric.com/articles/cladboard/cladboard.html
If your device is assembled onto an etched circuit board, there's
no need to secure it further. If fact, an enclosure is only useful
while the assembly is being handled. Unless it's in danger of being
kicked or otherwise damaged after installation, or you need a metallic
enclosure for RFI protection, there's little value in even putting
a box around it.
A number of our products are offered sans enclosure and suggested that
they simple be installed as-is like this:
http://216.55.140.222/Catalog/AEC/9005/9005.jpg
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
Message 6
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| Subject: | Re: Need advice on small connector for |
avionics
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:43 AM 6/2/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: CardinalNSB@aol.com
>
>I would like to have small connectors between my audio panel and the various
>avionics for easy removal of tray and upgrade, or to just pull tray and be
>able to work behind the panel. I would appreciate thoughts and places to
>buy and
>brand name or an numbers.
>
>Also, can someone please give me a basic briefing of the pin insertion and
>retraction tools, are all Mollinex the same for instance or are there
>different
>sizes.
Every manufacturer of a removable pin connector uses unique tooling
unless the connector is built to some standard like the D-subs mentioned
below . . .
>Thank you Skip Simpson
The Type D Subminiature (D-sub) connectors like those on the back
of your computer are probably the most user friendly devices you can
get . . . prices and tooling are attractive too. See
http://www.aeroelectric.com/Catalog/tools/tools.html#rct-3
http://www.aeroelectric.com/Catalog/tools/tools.html#dse-1
http://www.aeroelectric.com/Catalog/connect/connect.html#S604
Shells for these connectors (as well as solder cub versions
of the connectors) are available from virtually every electronic
supply store not the least of which are Digikey and Radio Shack.
Bob . . .
Message 7
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| Subject: | Re: Odyssey PC680 terminal with larger ring |
terminal
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:09 PM 6/1/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: Jim Oke <wjoke@shaw.ca>
>
>The PC680 terminals use a female 6 mm metric thread. This is approximately
>1/4 inch for sizing ring terminals, but users will have to locate 6 mm
>bolts/cap screws or whatever to do the final connection. (Unless Odessy is
>including the bolts these days - they were not included with my PC680).
>
>Jim Oke
>Winnipeg, MB
Hawker supplies hardware with the batteries but they're packaged
separately. Many distributors don't take pains to make sure the
little bag of hardware goes out with the battery.
Bob . . .
Message 8
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| Subject: | Re: 10nF mylar cap. |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:43 PM 6/1/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: "Rob W M Shipley" <Rob@RobsGlass.com>
>
>I decided that I'd like to make the warning circuit Jim Weir put in this
>months KitPlanes. I visited my local Radio Shack and was able to get
>everything except the 10nF mylar capacitor. They told me that they have
>never stocked capacitors this small!!!! All the other local sources had
>nothing either and I'm reluctant to try Mouser or Digikey for one mylar
>capacitor.
>Does aanyone have any suggestions or better yet does anyone have one of
>these they could sell me?
>Any help gratefully received.
Yup, you got questions, they got answers.
"nano" is 10 to the minus 9th exponent. In the US
manufacturers and designers have largely ignored this multiplier
preferring to use "micro" (10 to the minus 6) and
"pico" (10 to the minus 12) multipliers.
Electronics diagrams from other parts of the world
have taken advantage of the intermediate nano multiplier
ever since I can remember . . .
1 nF is 1000 pF and .001 mF
So the 10 nF capacitor callout can also be written
as .01 mF or 10,000 pF . . . and Radio Shack has
had them since day-one.
Bob . . .
Message 9
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| Subject: | Re: Odyssey PC680 terminal with larger ring |
terminal
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 07:45 PM 6/1/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: "Dan Checkoway" <dan@rvproject.com>
>
>The cap screws on the Odyssey PC680's terminals are 3/16" (I believe). I
>was planning on using the 2 AWG 5/16" ring terminals that came with Van's
>basic wiring kit.
>
>How have others handled this...do you have to use ring terminals with a
>smaller hole, or can you use the 5/16" terminal? It looks like once
>tightened it'll be fine, but I'm curious if it's generally acceptable that
>way.
>
>Sorry if there's an obvious answer to this...
It's best to get a terminal that fits the screw . . . electrical
connection integrity is a function of PRESSURE that the threaded
fasteners are expected to place on the mated parts. If the hole
in a terminal is oversized, the ability of a fastener to provide
this pressure is compromised. B&C can supply you with terminals
with exactly the hole size you need.
Bob . . .
Message 10
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 06:55 PM 6/1/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: Bobdeva@aol.com
>
>Bob
>I'm trying to download Z11 in order to get a more legible copy than the one
>in the Aeroelectric Connection. I want to enlarge it to make it more
>compatible with a pair of 72 year old eyes. When I download it, all I get
>is a lot of
>text/garbage not the drawing. What am I doing wrong. Airplanes I know...
>computers, well that's another story.
Sounds like you were looking at or trying to print the file
contents without using the appropriate application to open
it. The drawings are in .dwg format by AutoCAD and are compatible
with a number of other cad programs not the least of which are
those supplied on the CD rom from our website.
The CD can be downloaded at
http://216.55.140.222/CD/AEC8_0.zip
or purchased at
http://www.aeroelectric.com/Catalog/AECcatalog.html
Bob . . .
Message 11
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| Subject: | Re: battery bus directly from battery |
terminal?
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 12:37 AM 6/2/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: "Dan Checkoway" <dan@rvproject.com>
>
>Bob,
>
>In all of the Z figures the battery bus is supplied power from a wire that
>comes off the "always hot" terminal of the battery contactor. In my
>particular case, because of where I would like to mount the battery bus fuse
>block, I'd like to power the it directly from the battery's (+) terminal in
>order to satisfy the "6 inches or less" requirement and still be able to
>locate the battery bus fuse block in a reasonable location.
>
>Is this acceptable, wiring directly from the (+) terminal as opposed to from
>the contactor's hot terminal?
>
>If so, is there any advantage or disadvantage to using a separate ring
>terminal vs. soldering the smaller battery bus wire right into the 2 AWG
>ring terminal for the wire to the battery contactor? I figure a separate
>ring terminal (and just stack 'em) makes the most sense but figured I'd ask.
Stacking terminals is fine. But I wouldn't loose any sleep over
the 6" rule-of-thumb either. I think there is value in having the
battery bus feed come from a relatively permanent connection like
the battery contactor as opposed to using a termination subject
to routine maintenance . . .
Bob . . .
Message 12
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| Subject: | Re: Odyssey PC680 terminal with larger ring terminal |
--> AeroElectric-List message posted by: HCRV6@aol.com
In a message dated 6/1/03 7:50:40 PM Pacific Daylight Time, dan@rvproject.com
writes:
<< The cap screws on the Odyssey PC680's terminals are 3/16" (I believe). I
was planning on using the 2 AWG 5/16" ring terminals that came with Van's
basic wiring kit. >>
I have what is supposed to be a clone of the PC 680 from Battery Web .com.
The terminal cap screws on my battery are metric size 10, or 0.224 in. I used
a "D" drill to open the holes in some 3/16" terminals. Worked for me.
Harry Crosby
Pleasanton, California
RV-6, firewall forward
Message 13
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| Subject: | Re: Need advice on small connector for avionics |
--> AeroElectric-List message posted by: DHPHKH@aol.com
Skip,
Unsolicited testimonial: The RCT-3 crimp tool found on Bob's website works
great.
With this tool and a bag of machined male and female pins, building up d-subs
is very fast. Strip the wire, drop a pin in the tool, crimp, plug it into
the d-sub connector body. When all the wires are in there, add the shell and
you're done.
Dan
Message 14
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| Subject: | Re: Need advice on small connector for |
avionics
--> AeroElectric-List message posted by: "Larry Bowen" <Larry@bowenaero.com>
Ditto. I used it for my AP wiring. Worked very well. Those pins are
expensive, but the end result is very nice.
-
Larry Bowen
Larry@BowenAero.com
http://BowenAero.com
do not archive
DHPHKH@aol.com said:
> --> AeroElectric-List message posted by: DHPHKH@aol.com
>
> Skip,
> Unsolicited testimonial: The RCT-3 crimp tool found on Bob's website
> works great.
> With this tool and a bag of machined male and female pins, building
> up d-subs is very fast. Strip the wire, drop a pin in the tool,
> crimp, plug it into the d-sub connector body. When all the wires are
> in there, add the shell and you're done.
>
> Dan
Message 15
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| Subject: | RE: RF burns from antenna . . .fact or mythology ? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 10:12 PM 5/31/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "James E. Clark"
><james@nextupventures.com>
>
>I have been burned by the RF from a ham radio.
>
>Touching one of those antennas during a transmission is NOT a "cool" thing
>to do.
>
>What happens is that you do NOT kow you are being burned until it is way too
>late. It is like the RF is boiling the blood inside your finger and you
>don't notice until it reaches the boiling point. Once I let go of the
>antenna (it was on a roof and someone transmitted when I did not expect such
>to occur) that is when it really burned for a while.
>
>I don't know how much energy was transmitted into my fingers but I do know
>it was enough. It is probably kinda like you don't want to be inside a
>microwave oven while it is on. It won't get hot but your insides REALLY
>will.
Don't know about the blood boiling bit . . . but consider
the following:
The dielectric strength of air is about 1,000 volts per
.001" of airspace. This is means that if you put your finger
within .001" of a conductor carrying 1,000 volts more potential
than your body, you can get a arc. Once the arc starts, air
in intervening space is ionized and it now takes much less
than 1,000 volts to sustain the arc.
An arc is HOT . . . energy is released in a relatively small
volume which elevates temperatures in the arc to well over
1,000 degrees. Boil blood? Probably. Cook meat? Probably.
Get your attention via the nervous system? One certainly
hopes so.
How does that voltage get there? Take a peek at Figure 13-5
in the 'Connection. Hmmm . . . just noticed an error in
that figure . . . the bottom label on the y-axis is zero.
It should be minimum . . . I've fixed the figure and uploaded
to http://216.55.140.222/temp/DIPOLE.pdf
Anywho, this figure illustrates the distribution of voltage
across the antenna's length. A 1/2-wave dipole is shown,
a 1/4-wave vertical monopole is similar . . just half the
structure.
If we're conducting 5-watts of power into the low impedance
point on the antenna (center or base) then voltage at the
base will be on the order of E(squared)/R=watts or
E(squared)= 5-Watts * 50-Ohms = 16 volts.
Now, as you move toward the end of the antenna the current
in antenna rod goes down while the voltage goes up. How high?
Saw the reasoning behind that calculation once but don't recall
now what it was . . . but trust me, at the FREE END of an
antenna, the voltage can become high enough to get your
attention.
Recall that a laser rated in a few hundred milliwatts is
capable of concentrating that power into a very small area
so that POWER DENSITY (watts/cc) can be a spectacular
number. Same thing happens with the itty-bitty transmitter
arcing off the top of an antenna to your finger. It may
not excite a LOT of nerves but the few it does hammer
on get really irritated.
Frequency of the energy has an effect too. 130 Mhz RF
is more penetrating and will propagate across smaller
gaps that DC. I've held my hand in front of an operating
radar antenna on the B-52 and felt a slight warming.
In years past, doctors hooked patients up to diathermy machines
operating at 27 MHz for the therapeutic value of
deep penetration heating effects. Got one of those
treatments for a kidney disorder when I was a teenager.
I've not seen such a machine in a doctor's office
in about 45 years but the machines are still out there.
See
http://www.mettlerelec.com/diatherm.html
http://www.fda.gov/cdrh/safety/121902.pdf
http://www.orthoteers.co.uk/Nrujp~ij33lm/Orthdiathermy.htm
https://www.dmc.org/health_info/topics/spor3327.html
Here are links where higher energy densities are
used for surgical effects.
http://www.mbnsclinic.co.uk/diathermy.htm
http://www.cochrane.org/cochrane/revabstr/ab002211.htm
While radio frequency energy has qualities different than
DC or ordinary line frequency AC . . . it's not particularly
"magic" . . . just simple-idea based physics.
Bob . . .
Message 16
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| Subject: | My Fuel Gauge Design |
--> AeroElectric-List message posted by: j1j2h3@juno.com
Let me see if I have this straight. I fill up my tank, measuring the
amount I put in, to determine its exact capacity. Then I calculate each
of the percentages. Now I dump out the tank contents and put in 4.4% of
the total. Now I adjust the location of the lowest thermistor. Now I
add enough more to bring the total up to 6.2%, then adjust the location
of the second thermistor. I then repeat this step for the remaining 8
thermistors. Boy, some people thought it was a lot of work to adjust
some screws for one of the other guages. ;)
Jim Hasper - RV-7 just starting empennage (on hold pending move to
Tennessee)
Do not archive
On 6/1/03, Eric M. Jones" <emjones@charter.net> wrote:
(snip)
Eric says--I don't know. Adjustments can be made. (Just to be sure we're
clear--the
4.4% is close to the bottom) I just bought 4000 PTC thermistors 0805
chips
on eBay for $4. They are not quite what I wanted but.....cheap!
The best thing to hit the internet in years - Juno SpeedBand!
Surf the web up to FIVE TIMES FASTER!
Message 17
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| Subject: | Re: Cheap blind encoder. |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
>
>Hi Bob and all,
>
>What could be a simple way to make the above etched circuit board ? I'm not
>equipped for etching circuits, nor designing them.
>Any suggestions ?
>
>Thanks,
>Gilles
There's free diy software for crafting and ordering
boards available from
http://www.expresspcb.com/
I'm not sure they can or will ship internationally.
I could do the layout, order the boards and then
forward them to you. How many radios are you tying
to the encoder and how many of them do not already
have isolation diodes?
Bob . . .
Message 18
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| Subject: | Fuel gauge design |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>--> AeroElectric-List message posted by: j1j2h3@juno.com
>Let me see if I have this straight. I fill up my tank, measuring the
>amount I put in, to determine its exact capacity. Then I calculate each
>of the percentages. Now I dump out the tank contents and put in 4.4% of
>the total. Now I adjust the location of the lowest thermistor. Now I
>add enough more to bring the total up to 6.2%, then adjust the location
>of the second thermistor. I then repeat this step for the remaining 8
>thermistors. Boy, some people thought it was a lot of work to adjust
>some screws for one of the other guages. ;)
>Jim Hasper - RV-7 just starting empennage (on hold pending move to
>Tennessee)
>Do not archive
Negatory Jim---I don't propose any such thing. But if I sold fuel senders in
convenient sizes, just like the capacitive sender people do, then this would
be how they would be arranged arranged. Forgive the decimal points, that's
just for calculation. You could have a conventional unit gauge arrangement
if you wanted it too..
I was only trying to make a couple of points--
1) that PTC thermistor chips might be easy to apply to this task and I
intend to build one for test.
2) logarithmic readings would make up for the bar graph steps. National
Semiconductor makes a log bar graph driver. so it's easy. Non-linearity in
this case might be a great thing.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
Message 19
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| Subject: | Re: Cheap blind encoder. |
--> AeroElectric-List message posted by: "Gilles.Thesee" <Gilles.Thesee@ac-grenoble.fr>
----- Message d'origine -----
De : "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
: <aeroelectric-list@matronics.com>
Envoy : lundi 2 juin 2003 20:49
Objet : Re: AeroElectric-List: Cheap blind encoder.
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
>
>
> >
> >Hi Bob and all,
> >
> >What could be a simple way to make the above etched circuit board ? I'm
not
> >equipped for etching circuits, nor designing them.
> >Any suggestions ?
> >
> >Thanks,
> >Gilles
>
> There's free diy software for crafting and ordering
> boards available from
> http://www.expresspcb.com/
>
> I'm not sure they can or will ship internationally.
> I could do the layout, order the boards and then
> forward them to you. How many radios are you tying
> to the encoder and how many of them do not already
> have isolation diodes?
>
> Bob . . .
>
Bob,
Thanks for your offer.
I downloaded the software and I'll try to produce an acceptable setup.
My intention is to connect a Garmin GPS 400 and a Becker ATC-4401
transponder to an Ameri-King 350 encoder.
The GPs already has the diodes built in. I don't know yet for the Becker. I
asked them but no response to date. As soon as the radios arrive I'll
perform the test you described.
Or maybe someone around knows for the Becker ?
Cheers,
Gilles
Message 20
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| Subject: | PTT - Ground Wire |
--> AeroElectric-List message posted by: "Duane Bentley" <dbentley@fuse.net>
I had an avionics shop build the wire harnesses for my nav / com radios.
It all looks good except for a question on the PTT wiring. The UPS SL15
manual shows the PTT switch wired between the Mic PTT (tip) and Mic Lo
(ring) on the Mic jack, that is, two wires in a closed circuit with the
switch in between. The Mic Lo then goes to on to ground in the system.
My avionics guy ran just one wire from the Mic PTT (tip) to the actual
PTT switch and told me to take the other side of the PTT switch to
ground. It all looks good, logically, but is different that the closed
circuit diagram as well as the ones that Bob has printed as examples.
Is this proposal going to cause me problems, with not running another
wire back to the mic jack?
Duane
Message 21
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| Subject: | Cheap blind encoder. |
--> AeroElectric-List message posted by: "Don Honabach" <don@pcperfect.com>
>> What could be a simple way to make the above etched circuit board ?
You may also want to try a do it yourself home project for the PCB. A
lot of electronic stores have kits that you buy to make your own PCBs at
home.
I got into this about a year or so ago to make a USB based ISO7816 data
logger for my business to help better understand how these devices work.
After a few attempts I was able to make some really nice boards that
used surface mounted uControllers with a 100+ pin count by using just my
laser printer, some paper, UV light, and required chemicals. If you've
ever developed pictures the 'old fashion way' it's pretty much the same.
Only hard part is getting a good starting image when dealing with super
small surface mount ICs and traces, but for the diode project any old
laser printer or even an inkjet would work fine.
Good Luck,
Don
-----Original Message-----
From: Robert L. Nuckolls, III [mailto:bob.nuckolls@cox.net]
Subject: Re: AeroElectric-List: Cheap blind encoder.
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
--> <bob.nuckolls@cox.net>
>
>Hi Bob and all,
>
>What could be a simple way to make the above etched circuit board ? I'm
>not equipped for etching circuits, nor designing them. Any suggestions
>?
>
>Thanks,
>Gilles
There's free diy software for crafting and ordering
boards available from
http://www.expresspcb.com/
I'm not sure they can or will ship internationally.
I could do the layout, order the boards and then
forward them to you. How many radios are you tying
to the encoder and how many of them do not already
have isolation diodes?
Bob . . .
direct advertising on the Matronics Forums.
Message 22
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| Subject: | Re: Cheap blind encoder. |
--> AeroElectric-List message posted by: Rino <lacombr@nbnet.nb.ca>
You may want to check these people on yet a different technique of
making PCBs
This is the method I prefer.
Rino
http://www.mnsi.net/~boucher/makepcbs.htm
Don Honabach wrote:
>
> --> AeroElectric-List message posted by: "Don Honabach" <don@pcperfect.com>
>
> >> What could be a simple way to make the above etched circuit board ?
>
> You may also want to try a do it yourself home project for the PCB. A
> lot of electronic stores have kits that you buy to make your own PCBs at
> home.
>
> I got into this about a year or so ago to make a USB based ISO7816 data
> logger for my business to help better understand how these devices work.
> After a few attempts I was able to make some really nice boards that
> used surface mounted uControllers with a 100+ pin count by using just my
> laser printer, some paper, UV light, and required chemicals. If you've
> ever developed pictures the 'old fashion way' it's pretty much the same.
> Only hard part is getting a good starting image when dealing with super
> small surface mount ICs and traces, but for the diode project any old
> laser printer or even an inkjet would work fine.
>
> Good Luck,
> Don
>
> -----Original Message-----
> From: Robert L. Nuckolls, III [mailto:bob.nuckolls@cox.net]
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List: Cheap blind encoder.
>
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> --> <bob.nuckolls@cox.net>
>
> >
> >Hi Bob and all,
> >
> >What could be a simple way to make the above etched circuit board ? I'm
>
> >not equipped for etching circuits, nor designing them. Any suggestions
> >?
> >
> >Thanks,
> >Gilles
>
> There's free diy software for crafting and ordering
> boards available from
> http://www.expresspcb.com/
>
> I'm not sure they can or will ship internationally.
> I could do the layout, order the boards and then
> forward them to you. How many radios are you tying
> to the encoder and how many of them do not already
> have isolation diodes?
>
> Bob . . .
>
> direct advertising on the Matronics Forums.
>
--
Message 23
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| Subject: | Re: PTT - Ground Wire |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 07:00 PM 6/2/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: "Duane Bentley" <dbentley@fuse.net>
>
>I had an avionics shop build the wire harnesses for my nav / com radios.
>It all looks good except for a question on the PTT wiring. The UPS SL15
>manual shows the PTT switch wired between the Mic PTT (tip) and Mic Lo
>(ring) on the Mic jack, that is, two wires in a closed circuit with the
>switch in between. The Mic Lo then goes to on to ground in the system.
>
>
>My avionics guy ran just one wire from the Mic PTT (tip) to the actual
>PTT switch and told me to take the other side of the PTT switch to
>ground. It all looks good, logically, but is different that the closed
>circuit diagram as well as the ones that Bob has printed as examples.
>Is this proposal going to cause me problems, with not running another
>wire back to the mic jack?
The "ring" terminal is microphone HI . . . are you sure their
diagram doesn't show connection to the "barrel" or "sleeve"
connection which then goes to ground? The barrel or sleeve
connection is usually MIC LO and PTT return to ground.
The tech's suggestion is how tens of thousands of external
PTT switches have been wired and will probably be okay.
Bob . . .
Message 24
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--> AeroElectric-List message posted by: "Rob W M Shipley" <Rob@RobsGlass.com>
Many thanks to James Jula and John Loram for lightening my darkness and kindly
explaining how these units work.
Fly safe everyone.Rob
Rob W M Shipley
RV9A N919RV Fuselage - now a canoe!!!
Do not archive
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