Today's Message Index:
----------------------
1. 06:06 AM - Re: Re: Failed brownout battery experiment (Robert L. Nuckolls, III)
2. 06:09 AM - Re: Re: Failed brownout battery experiment (Robert L. Nuckolls, III)
3. 06:17 AM - Re: Re: failed (?) brownout experiment (Robert L. Nuckolls, III)
4. 08:04 AM - Re: De-Slumpifier, Voltage Buffer to Prevent Brownout (Eric M. Jones)
5. 09:21 AM - Multiplexing 7-segment LED displays (James Kilford)
6. 11:38 AM - Re: Multiplexing 7-segment LED displays (Robert L. Nuckolls, III)
7. 12:21 PM - Re: Multiplexing 7-segment LED displays (James Kilford)
8. 09:31 PM - Re: Matronics Email List Wiki! (mahjabeen)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Failed brownout battery experiment |
At 06:55 PM 9/25/2013, you wrote:
>
>http://www.ebay.com/itm/Auto-DC-Boost-Buck-Adjustable-Converter-Solar-Volt-Regulator-4-5-32V-to-1-25-32V-/350854774856?ssPageName=ADME:L:OU:US:3160
>Above is a link to the voltage booster that I ordered. It only cost
>$3.25. They say you get what you pay for. It cost a little more
>than some others, but still cheap. The copper coils looked
>impressive compared to some other units without them. I can not
>find any more like mine for sale on eBay. People must not be
>satisfied with them or else they would still be for sale. I bench
>tested it before giving the seller positive feedback. But I
>neglected to check the AC component of the output until it failed to
>power the Dynon D-180. Do you still want me to send the unit to you
>Bob, or should we just consider it a poor design and toss it?
No, go ahead and send it to me. This part my be performing
exactly as it was predicted. It's probably too small for the
application. I'm not sure about the "AC component"
I'll look at that when it gets here.
Bob . . .
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Failed brownout battery experiment |
At 10:34 AM 9/26/2013, you wrote:
>
>The 28 volts AC that I measured using a cheap digital meter in the
>hangar was completely wrong. Testing the DC -DC voltage booster in
>my home workshop, my Fluke 76 true RMS meter displayed 1.6mv AC. My
>oscilloscope showed 12mv peak to peak ripple at a frequency of
>400KHz. I connected a 1141 automotive lamp (1.4 amp) to the ouput
>of the voltage booster to simulate the Dynon D-180 load. Even
>though the voltage booster was set at 13 volts with no load, under
>load the voltage dropped over time to less than 10 volts. So that
>is why the Dynon continuously booted up and shut off. The Dynon
>would see 13 volts and turn on. As the voltage from the booster
>dropped off, the Dynon would shut off.
> Next I adjusted the pot on the voltage booster to give 25 volts
> output with no load. Then I connected the lamp. The voltage
> immediately dropped to 13 volts, then slowly dropped to less than
> 10 volts over a period of about 3 minutes.
> I noticed that negative input and negative output are connected
> together on the circuit board. It seems that the output voltage
> drops off as the IC heats up. It does not get hot enough to burn,
> but it is too hot to hold a finger on.
> I have concluded that if this voltage booster gets its power from
> the starter circuit, it should prevent a brownout during engine
> start. However, it is incapable of supplying power for longer than
> a few seconds.
> To Henador, no I never reversed the input polarity.
>To Bob, since I have bench tested the voltage booster, I will not
>send it to you unless you still want it. Do you?
>I will test Eric's DeSlumpifier when it arrives.
This confirms my suspicion that the part was
too small for the task.
Bob . . .
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: failed (?) brownout experiment |
At 11:47 PM 9/26/2013, you wrote:
>
>I'm not so sure...
>
>The description and photos of the board Joe bought show a buck/boost
>unit, but the LM2577 is a boost/flyback IC. With the part number
>obliterated in the eBay photos, we can't really know for sure. That
>was probably done because the IC is a black market knockoff, which I
>believe is common on these kinds of inexpensive boards from
>China. How else do they deliver them halfway around the world for
>the price of the IC alone?
The power requirements are simply too
great for any of the LM2577 class devices
irrespective of their pedigree.
I would have tride a converter more along
these lines . . .
http://tinyurl.com/n7rsteo
Given the very short and widely spaced
loading in this application, the heat sink
would not be necessary . . . but the ability
to grunt a 50W+ load is critical to preventing
it from falling out of bed.
Bob . . .
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: De-Slumpifier, Voltage Buffer to Prevent Brownout |
> OK, I'll bite. What is a De-Slumpifier?
De-Slumpifier: A Supercapacitor device to prevent voltage slumps. Particularly
to prevent microprocessors from rebooting when the battery voltage is pulled down
trying to start the aircraft.
This particular design is for 12V and has 250,000 uF. It can be modified if you
understand what it does, to support many similar applications. I have posted
schematics and parts list and my giant giant enormous hand holding a prototype
(elsewhere here).
> I'll take a stab that this is a replacement for the typical filter Capacitor
for Alternator, and if so does your device save weight?
A typical filter caps is a pretty small and simple part. You wouldn't save much,
I think.
> SeaRey Amphibian, framework and hull assembled and covered. Working on VFR avionics
and wiring (Dynon Skyview full suite)and Paint. Top Priority is keep it
light, and place weight forward!
If you aren't using my special Super-8-CCA battery cable, then you haven't yet
heard about it. See may website. Buy 50'. Save pounds.
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=409348#409348
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Multiplexing 7-segment LED displays |
I'm wondering if anyone can answer this question:
I'd like to build a new fuel gauge based around 7-segment LED displays,
driven by a PIC / Arduino, etc. Instead of running dozens of IO lines, I'd
like to multiplex the displays so that the total number of lines is 7 +
(no. of digits).
The idea would be to switch on a common line for each digit in turn, and
set the state for the seven segment lines for the digit that's currently
lit.
I hope that makes sense.
Anyway, I'm sure the software will be straightforward enough (he says!) but
it's the circuitry with which I need some help. Can anyone recommend a few
components to drive the LED displays from the PIC, along with a circuit
diagram? I have a bunch of resistors and general purpose transistors in my
electronics kit. I'd probably test this on a PIC18F4680, because I have a
neat little prototype board with this particular chip, along with HDSP-315E
7-segment digits, which is a common anode type.
Happy to share my findings with anyone who's interested!
Many thanks,
James
Message 6
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Multiplexing 7-segment LED displays |
At 11:20 AM 9/27/2013, you wrote:
I'm wondering if anyone can answer this question:=C2
I'd like to build a new fuel gauge based around
7-segment LED displays, driven by a PIC /
Arduino, etc. =C2 Instead of running dozens of IO
lines, I'd like to multiplex the displays so that
the total number of lines is 7 + (no. of digits). =C2
The idea would be to switch on a common line for
each digit in turn, and set the state for the
seven segment lines for the digit that's currently lit. =C2
I hope that makes sense.
That's the way it's usually done. I don't think anybody runs
multiple 7-segment displays statically.
Anyway, I'm sure the software will be
straightforward enough (he says!) but it's the
circuitry with which I need some help. =C2 Can
anyone recommend a few components to drive the
LED displays from the PIC, along with a circuit
diagram? =C2 I have a bunch of resistors and
general purpose transistors in my electronics
kit. =C2 I'd probably test this on a PIC18F4680,
because I have a neat little prototype board with
this particular chip, along with HDSP-315E
7-segment digits, which is a=C2 common anode type.=C2
The pull down capability of a PIC port is on the order
of 30mA Your common anode displays would be switched
on, in turn, by pulling down on the base of a PNP transistor.
The collector of said transistor would drive the anode
of one display . . . possible fitted with a resistor to
limit current.
This image shows the general arrangement . . . in this
case segment current limits are in the cathodes . . . it
can be on the anode side if you light only one segment at
a time, if it's one full digit at a time, you'll want to
use cathode positioned current limits.
See http://tinyurl.com/ks5aos5
http://embedded-lab.com/blog/wp-content/uploads/2011/03/Lab11_C
There are a host of approaches for both schematic and source
codes published on the net.
See:
http://tinyurl.com/m5wffq5
How do you plan to sense liquid level?
Bob . . .
Message 7
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Multiplexing 7-segment LED displays |
> This image shows the general arrangement
Thanks Bob, that's a great help, thanks. I'll breadboard it and see how I
get on. Presumably with your circuit, if I assemble the transistor / LED
arrays, I can test them by putting 5V into the resistors, just like the PIC
outputs would.
> How do you plan to sense liquid level?
I have three of the excellent Princeton capacitive sensors. After
calibration, they will linearise a fuel tank's output and give a 0 - 5V
output from empty to full.
I've produced a version using a colour LCD, and the software works well,
but it's not very clear in direct sunlight. The great thing about the LCD
though is the ability to show fuel quantities in red or green according to
the level in a particular tank, e.g. <10% = red.
The ideal thing would be to find a nice bright OLED display. That would be
the best of both worlds. I have ideas about an all-in-one OLED instrument
that would show fuel, temperatures, pressures, etc. -- a complete engine
management system in one drop-in 2-1/4" or 3-1/8" package. I have
thermocouple chips ready to do some prototyping... but I'm short on time
and have to stick to paying projects at the moment.
James
On 27 September 2013 19:37, Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 11:20 AM 9/27/2013, you wrote:
> I'm wondering if anyone can answer this question:=C3=82
>
> I'd like to build a new fuel gauge based around 7-segment LED displays,
> driven by a PIC / Arduino, etc. =C3=82 Instead of running dozens of IO li
nes,
> I'd like to multiplex the displays so that the total number of lines is 7
> (no. of digits). =C3=82
>
> The idea would be to switch on a common line for each digit in turn, and
> set the state for the seven segment lines for the digit that's currently
> lit. =C3=82
>
> I hope that makes sense.
>
> That's the way it's usually done. I don't think anybody runs
> multiple 7-segment displays statically.
>
> Anyway, I'm sure the software will be straightforward enough (he says!)
> but it's the circuitry with which I need some help. =C3=82 Can anyone rec
ommend
> a few components to drive the LED displays from the PIC, along with a
> circuit diagram? =C3=82 I have a bunch of resistors and general purpose
> transistors in my electronics kit. =C3=82 I'd probably test this on a
> PIC18F4680, because I have a neat little prototype board with this
> particular chip, along with HDSP-315E 7-segment digits, which is a=C3=82
common
> anode type.=C3=82
>
> The pull down capability of a PIC port is on the order
> of 30mA Your common anode displays would be switched
> on, in turn, by pulling down on the base of a PNP transistor.
> The collector of said transistor would drive the anode
> of one display . . . possible fitted with a resistor to
> limit current.
>
> This image shows the general arrangement . . . in this
> case segment current limits are in the cathodes . . . it
> can be on the anode side if you light only one segment at
> a time, if it's one full digit at a time, you'll want to
> use cathode positioned current limits.
>
> See http://tinyurl.com/ks5aos5
> [image: http://embedded-lab.com/blog/wp-content/uploads/2011/03/Lab11_C]
>
> There are a host of approaches for both schematic and source
> codes published on the net.
>
> See:
>
> http://tinyurl.com/m5wffq5
>
> How do you plan to sense liquid level?
>
> **
>
> ** Bob . . .
>
> *
>
===========
===========
===========
===========
> *
>
>
Message 8
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Matronics Email List Wiki! |
i would like to appreciate you for sharing such a great info with us
:o
--------
andy
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=409400#409400
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|