LED Display
Archiver
Posts: 46,084
Hi Chris,
I've seen some Boards with many displays where each display has
the driver IC bulit in and there was four lines for BCD and Select
line for each display.
Your board sounds like each display on the board has common
pin to all the digits and you either need to ground that pin or supply
it with 5 volts (don't forget a current limiting resistor) and then you'd
use just one display driver chip for all the displays and select the
display you want with the common pin(as I talked about above).
I hope this helps I'm getting ready to leave and in hurry.
Michael Fowler
C Programmer
I've seen some Boards with many displays where each display has
the driver IC bulit in and there was four lines for BCD and Select
line for each display.
Your board sounds like each display on the board has common
pin to all the digits and you either need to ground that pin or supply
it with 5 volts (don't forget a current limiting resistor) and then you'd
use just one display driver chip for all the displays and select the
display you want with the common pin(as I talked about above).
I hope this helps I'm getting ready to leave and in hurry.
Michael Fowler
C Programmer
Comments
I am looking for an outdoor led display that I can connect to a·basic stamp.
It needs to be a Single Line, 6 digit display (ie to display: 145.58· )
Readable from 75 -·400 feet (8 - 10" letters), in direct sunlight outdoors.
Thanks for your help
side, "APLUS BT-M405RE". I am trying to interface to the stamp, but
can't find it pin out data. Did a google search with no results. Any
ideas on how I might find the pin out on this thing?
Thanks so much for your help..
Leroy
I found the specifications with the following in google search;
1) search for LED or LED's.
2) then search within results for displays.
3) then search within results for APLUS.
4) this will give you the APLUS home page at the top of the list,
bookmark this site.
5) then use their search to find your part.
Here is the destination that will have your information;
http://www.aplusproducts.com/Leds/LED_Displays/PDF/d-three-type2.pdf
You need to learn on how to do better searches using Google Search.
Have Fun !!
Dale Fleischmann
Leroy Hall wrote:
> I have a seven segment LED display, red digits, 3 characters. On it's
> side, "APLUS BT-M405RE". I am trying to interface to the stamp, but
> can't find it pin out data. Did a google search with no results. Any
> ideas on how I might find the pin out on this thing?
>
> Thanks so much for your help..
>
> Leroy
>
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[noparse][[/noparse]Non-text portions of this message have been removed]
This is a little off topic, but I'm working on a project that needs a
four digit LED Display. I have looked in digikey, mouser, and jameco,
but haven't found the size I need with four digits. Does it matter if I
get four single digit displays and put them right next to each other?
I'm using the max7219 to control it.
-Mike
[noparse][[/noparse]Non-text portions of this message have been removed]
Note the 7219 chip comes in two flavors,
common anode and common cathode. Your
LED displays MUST be the same kind as
the 7219 you have for it to work.
The 'common anode' means all the anodes
of all the LED's are tied together. To
light one LED, you drive its cathode,
which does have its own pin. This cuts
down on the number of wires.
--- In basicstamps@yahoogroups.com, "Mike Dillon" <laxboy687@e...>
wrote:
> Hey,
>
> This is a little off topic, but I'm working on a project that needs
a
> four digit LED Display. I have looked in digikey, mouser, and
jameco,
> but haven't found the size I need with four digits. Does it matter
if I
> get four single digit displays and put them right next to each
other?
> I'm using the max7219 to control it.
>
> -Mike
>
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
placing them right next to each other. In my experience, using displays from
the same "family" look good right next to each other. I bought these from
Digikey. To interface to them, I have a Maxim ICM7218A (8 digit driver),
using two of the digits of the driver to drive three other dots on the
displays (a ":" and a degree symbol [noparse][[/noparse]that's what I use them for, anyway]).
Using a 74F675 (serial to parallel shift register), I can interface with the
display using only 4 pins of my BS2. I used to be able to use three pins,
combining the functions of loading the output of the shift register with the
loading of the registers in the driver chip (through an inverter), but when
I put an ADC on my breadboard this stopped working (some sort of noise I
guess!).
To send updates to the display driver only required a very short segment of
PBASIC code. I can share it if you want.
Steve
Original Message
From: "Mike Dillon" <laxboy687@e...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, July 15, 2003 7:48 PM
Subject: [noparse][[/noparse]basicstamps] Led Display
> Hey,
>
> This is a little off topic, but I'm working on a project that needs a
> four digit LED Display. I have looked in digikey, mouser, and jameco,
> but haven't found the size I need with four digits. Does it matter if I
> get four single digit displays and put them right next to each other?
> I'm using the max7219 to control it.
>
> -Mike
>
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
I want to blank single digits from my 6 (well, 8) digit display. These are
common-anode displays. I tried putting a transistor to the anode side of one
digit (again, confusion - "anode" to me means "negative", but the rest of
the world is backwards [noparse]:)[/noparse]... Anyway, the base of the NPN went to a stamp pin
for this test via a 10K resistor, the emitter going to the anode of the LED,
and the collector to the "DIGIT 8" pin of the driver. I noticed that this
digit was much dimmer than the rest, due to the Vce of the transistor I
assume. However, I accomplished blanking of that single digit. The driver IC
only alllows blanking of all or none.
How can I achieve this without too much loss of driver current? If I
remember right, a FET may be able to do a better job. Ideas?
Thanks!
Steve
Original Message
From: "Steve Ziuchkovski" <zman97211@y...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, July 15, 2003 8:25 PM
Subject: Re: [noparse][[/noparse]basicstamps] Led Display
> I currently use two LTC4624JF 3 digit 7 segment displays to get 6 digits,
> placing them right next to each other. In my experience, using displays
from
> the same "family" look good right next to each other. I bought these from
> Digikey. To interface to them, I have a Maxim ICM7218A (8 digit driver),
> using two of the digits of the driver to drive three other dots on the
> displays (a ":" and a degree symbol [noparse][[/noparse]that's what I use them for, anyway]).
> Using a 74F675 (serial to parallel shift register), I can interface with
the
> display using only 4 pins of my BS2. I used to be able to use three pins,
> combining the functions of loading the output of the shift register with
the
> loading of the registers in the driver chip (through an inverter), but
when
> I put an ADC on my breadboard this stopped working (some sort of noise I
> guess!).
>
> To send updates to the display driver only required a very short segment
of
> PBASIC code. I can share it if you want.
>
> Steve
>
>
Original Message
> From: "Mike Dillon" <laxboy687@e...>
> To: <basicstamps@yahoogroups.com>
> Sent: Tuesday, July 15, 2003 7:48 PM
> Subject: [noparse][[/noparse]basicstamps] Led Display
>
>
> > Hey,
> >
> > This is a little off topic, but I'm working on a project that needs a
> > four digit LED Display. I have looked in digikey, mouser, and jameco,
> > but haven't found the size I need with four digits. Does it matter if I
> > get four single digit displays and put them right next to each other?
> > I'm using the max7219 to control it.
> >
> > -Mike
> >
> >
> >
> > [noparse][[/noparse]Non-text portions of this message have been removed]
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject
and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
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>
2N2906
e c
anode 8 driver -->\___/--- anodes
|b
stamp pin --/\/\----'
1k
The display will be blanked when the Stamp pin is high. And it will
follow the driver when the Stamp pin is low. In this circuit you
will be using the PNP in the common emitter configuration with the
load on the collector, so the voltage drop across the transistor will
be only 0.1 or 0.2 volt. In your other configuration, you had the
NPN transistor connected in common collector (emitter follower)
configuration, and that automatically drops at least 0.7 volt.
You can do the above circuit alternatively with a P-channel logic
level mosfet, with the source connected to the anode driver.
p-ch mosfet
s d
anode 8 driver ---|===|--- anodes
|g
stamp pin --/\/\----'
1k
To add more confusion to the souce/sink question, observe that
p-channel mosfets usually have their source connected to the most
positive supply and referenced to flow of (+) charge carriers, while
n-channel mosfets have their source terminal connected to the most
negative supply, referenced to (-) charge carriers.
-- best regards
Tracy Allen
electronically monitored ecosystems
http://www.emesystems.com
mailto:tracy@e...
>Well - I've tried something new today!
>
>I want to blank single digits from my 6 (well, 8) digit display. These are
>common-anode displays. I tried putting a transistor to the anode side of one
>digit (again, confusion - "anode" to me means "negative", but the rest of
>the world is backwards [noparse]:)[/noparse]... Anyway, the base of the NPN went to a stamp pin
>for this test via a 10K resistor, the emitter going to the anode of the LED,
>and the collector to the "DIGIT 8" pin of the driver. I noticed that this
>digit was much dimmer than the rest, due to the Vce of the transistor I
>assume. However, I accomplished blanking of that single digit. The driver IC
>only alllows blanking of all or none.
>
>How can I achieve this without too much loss of driver current? If I
>remember right, a FET may be able to do a better job. Ideas?
>
>Thanks!
>Steve
to know.
-Mike
Original Message
From: Tracy Allen [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=iUYu-vcxETXJzH1KBhF_SeOAbCzqvc8USw9tpQOWvOoNoYoAOZA2LsF6a6MRMgvzKqAsr6k2GDvD4qQ]tracy@e...[/url
Sent: Tuesday, July 15, 2003 4:13 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Led Display
Use a PNP xistor instead of the NPN.
2N2906
e c
anode 8 driver -->\___/--- anodes
|b
stamp pin --/\/\----'
1k
The display will be blanked when the Stamp pin is high. And it will
follow the driver when the Stamp pin is low. In this circuit you
will be using the PNP in the common emitter configuration with the
load on the collector, so the voltage drop across the transistor will
be only 0.1 or 0.2 volt. In your other configuration, you had the
NPN transistor connected in common collector (emitter follower)
configuration, and that automatically drops at least 0.7 volt.
You can do the above circuit alternatively with a P-channel logic
level mosfet, with the source connected to the anode driver.
p-ch mosfet
s d
anode 8 driver ---|===|--- anodes
|g
stamp pin --/\/\----'
1k
To add more confusion to the souce/sink question, observe that
p-channel mosfets usually have their source connected to the most
positive supply and referenced to flow of (+) charge carriers, while
n-channel mosfets have their source terminal connected to the most
negative supply, referenced to (-) charge carriers.
-- best regards
Tracy Allen
electronically monitored ecosystems
http://www.emesystems.com
mailto:tracy@e...
>Well - I've tried something new today!
>
>I want to blank single digits from my 6 (well, 8) digit display. These
are
>common-anode displays. I tried putting a transistor to the anode side
of one
>digit (again, confusion - "anode" to me means "negative", but the rest
of
>the world is backwards [noparse]:)[/noparse]... Anyway, the base of the NPN went to a
stamp pin
>for this test via a 10K resistor, the emitter going to the anode of the
LED,
>and the collector to the "DIGIT 8" pin of the driver. I noticed that
this
>digit was much dimmer than the rest, due to the Vce of the transistor I
>assume. However, I accomplished blanking of that single digit. The
driver IC
>only alllows blanking of all or none.
>
>How can I achieve this without too much loss of driver current? If I
>remember right, a FET may be able to do a better job. Ideas?
>
>Thanks!
>Steve
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In this case I should use a PNP transistor.
Regards
ECO
Original Message
From: "Steve Ziuchkovski" <zman97211@y...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, July 15, 2003 9:21 PM
Subject: Re: [noparse][[/noparse]basicstamps] Led Display
> Well - I've tried something new today!
>
> I want to blank single digits from my 6 (well, 8) digit display. These are
> common-anode displays. I tried putting a transistor to the anode side of one
> digit (again, confusion - "anode" to me means "negative", but the rest of
> the world is backwards [noparse]:)[/noparse]... Anyway, the base of the NPN went to a stamp pin
> for this test via a 10K resistor, the emitter going to the anode of the LED,
> and the collector to the "DIGIT 8" pin of the driver. I noticed that this
> digit was much dimmer than the rest, due to the Vce of the transistor I
> assume. However, I accomplished blanking of that single digit. The driver IC
> only alllows blanking of all or none.
>
> How can I achieve this without too much loss of driver current? If I
> remember right, a FET may be able to do a better job. Ideas?
>
> Thanks!
> Steve
>
>
Original Message
> From: "Steve Ziuchkovski" <zman97211@y...>
> To: <basicstamps@yahoogroups.com>
> Sent: Tuesday, July 15, 2003 8:25 PM
> Subject: Re: [noparse][[/noparse]basicstamps] Led Display
>
>
> > I currently use two LTC4624JF 3 digit 7 segment displays to get 6 digits,
> > placing them right next to each other. In my experience, using displays
> from
> > the same "family" look good right next to each other. I bought these from
> > Digikey. To interface to them, I have a Maxim ICM7218A (8 digit driver),
> > using two of the digits of the driver to drive three other dots on the
> > displays (a ":" and a degree symbol [noparse][[/noparse]that's what I use them for, anyway]).
> > Using a 74F675 (serial to parallel shift register), I can interface with
> the
> > display using only 4 pins of my BS2. I used to be able to use three pins,
> > combining the functions of loading the output of the shift register with
> the
> > loading of the registers in the driver chip (through an inverter), but
> when
> > I put an ADC on my breadboard this stopped working (some sort of noise I
> > guess!).
> >
> > To send updates to the display driver only required a very short segment
> of
> > PBASIC code. I can share it if you want.
> >
> > Steve
> >
> >
Original Message
> > From: "Mike Dillon" <laxboy687@e...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Tuesday, July 15, 2003 7:48 PM
> > Subject: [noparse][[/noparse]basicstamps] Led Display
> >
> >
> > > Hey,
> > >
> > > This is a little off topic, but I'm working on a project that needs a
> > > four digit LED Display. I have looked in digikey, mouser, and jameco,
> > > but haven't found the size I need with four digits. Does it matter if I
> > > get four single digit displays and put them right next to each other?
> > > I'm using the max7219 to control it.
> > >
> > > -Mike
> > >
> > >
> > >
> > > [noparse][[/noparse]Non-text portions of this message have been removed]
> > >
> > >
> > > To UNSUBSCRIBE, just send mail to:
> > > basicstamps-unsubscribe@yahoogroups.com
> > > from the same email address that you subscribed. Text in the Subject
> and
> > Body of the message will be ignored.
> > >
> > >
> > > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
> > >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
> >
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>