Searching \ for '[PIC]: Flashing a LED' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/displays.htm?key=led
Search entire site for: 'Flashing a LED'.

Exact match. Not showing close matches.
PICList Thread
'[PIC]: Flashing a LED'
2001\03\28@120348 by Simon Ethier

flavicon
face
I have a small program to flash a led, when I program it in the PIC16F84A with  my P16PRO programmer, the LED is flashing BUT,  it ain't flashing as it is supposed to. Instead of bein "on" for 500ms (or so) and then shut off for another 500ms(or so), and then start this forever, the LED do this :

it goes on for about 500ms, then shut off for another 500ms, then in a 500ms laps time it does this :  it goes on for I'd say150ms, goes off for 150ms, then goes on for 150ms. After this, it starts again :  goes off for 500ms,  goes on for 150ms, off 150ms, etc...
So it seems the time it is supposed to be "on" for 500ms, in that period of time  it goes on, off, on

Anyone has an explanation for this ?
(I hope your were able to figure out what it is doing .... hehe)

thanks
---
Simon Ethier

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\03\28@122855 by Dale Botkin

flavicon
face
On Wed, 28 Mar 2001, Simon Ethier wrote:

> I have a small program to flash a led, when I program it in the
> PIC16F84A with my P16PRO programmer, the LED is flashing BUT, it ain't
> flashing as it is supposed to. Instead of bein "on" for 500ms (or so)
> and then shut off for another 500ms(or so), and then start this
> forever, the LED do this :
>
> it goes on for about 500ms, then shut off for another 500ms, then in a
> 500ms laps time it does this :  it goes on for I'd say150ms, goes off
> for 150ms, then goes on for 150ms. After this, it starts again :
> goes off for 500ms, goes on for 150ms, off 150ms, etc...
>
> So it seems the time it is supposed to be "on" for 500ms, in that
> period of time it goes on, off, on
>
> Anyone has an explanation for this ? (I hope your were able to figure
> out what it is doing .... hehe)

Yep - but no way we could figure out why without seeing the code.  Care
to post it?

Dale
---
The most exciting phrase to hear in science, the one that heralds new
discoveries, is not "Eureka!" (I found it!) but "That's funny ..."
               -- Isaac Asimov

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\03\28@124437 by Francois Robbertze

flavicon
face
Dear Simon,

I am not an expert with PIC, but I had my share of suffering to flash a
led...

Show your code to the piclist and if I can not help, there are plenty other
experts on the piclist that I am sure will be able to help...

Regards

Francois


{Original Message removed}

2001\03\28@132107 by Tony Pan

flavicon
face
I have seen similar thing once in my program. I figured that had to do with
my interrupt routine. I used it to do the timing and other stuffs; perhaps
it got too long trying to do too much at the same time. I don't know if
that was the cause, but after I shortened my interrupt routine it didn't
happen again. Try to see if that helps you.

Tony Pan


{Original Message removed}

2001\03\28@133740 by Simon Ethier

flavicon
face
Damm it ... sorry .. I forgot to post it ;-)
I also tried to light the LED via RA0, it worked but with the same problem a
RA4...

------- Begins here -------------
 Title  "PicNPoke Flash Program"

 list p=16f84    ; processor type
;
; The purpose of this program is to make a LED turn on and off
; The LED is connected to PortA, open collector pin RA4
; The flash rate is 500mS
;
PortA  equ 0x05  ; PortA RAM address
LED  equ 0x04  ; PortA RA4 = bit 4 for LED
TrisA  equ 0x85  ; TRISA RAM address
TrisB  equ 0x86  ; TRISB RAM address
Status  equ 0x03  ; Status RAM address
RP0  equ 0x05  ; Status RP0 bit = bit 5
DelayL  equ 0x0C  ; delay register LOW byte
DelayM  equ 0x0D  ; delay register MID byte
DelayH  equ 0x0E  ; delay register HIGH byte
;
; -------------
; PROGRAM START
; -------------
;
 org 0h   ; startup address = 0000

 bsf Status,RP0  ; set RP0 for RAM page 1
 clrf TrisA  ; all PortA = outputs
 clrf TrisB  ; all PortB = outputs
 bcf Status,RP0  ; set RP0 for RAM page 0

start  bcf PortA,LED  ; turn on LED on RA4
 call Delay500  ; execute a 500mS delay

 bsf PortA,LED  ; turn off LED on RA4
 call Delay500  ; execute a 500mS delay

 goto start  ; do this loop forever
;
; --------------------------------
; SUBROUTINE: waste time for 500mS
; --------------------------------
;
Delay500 clrf DelayL  ; /R clear DelayL to 0
 clrf DelayM  ; clear DelayM to 0
 movlw 3h  ; set DelayH to 3
 movwf DelayH
Wait1  decfsz DelayL  ; subtract 1 from DelayL
 goto Wait1  ; if not 0, goto Wait1
 decfsz DelayM  ; subtract 1 from DelayM
 goto Wait1  ; if not 0, goto Wait1
 decfsz DelayH  ; subtract 1 from DelayH
 goto Wait1  ; if not 0, goto Wait1
 return   ; finished the delay

 end

------- Ends here ---------------
{Original Message removed}

2001\03\28@141817 by Olin Lathrop

face picon face
>   list p=16f84    ; processor type
> ;
> ; The purpose of this program is to make a LED turn on and off
> ; The LED is connected to PortA, open collector pin RA4
> ; The flash rate is 500mS
> ;
> PortA  equ 0x05  ; PortA RAM address
> LED  equ 0x04  ; PortA RA4 = bit 4 for LED
> TrisA  equ 0x85  ; TRISA RAM address
> TrisB  equ 0x86  ; TRISB RAM address
> Status  equ 0x03  ; Status RAM address
> RP0  equ 0x05  ; Status RP0 bit = bit 5
> DelayL  equ 0x0C  ; delay register LOW byte
> DelayM  equ 0x0D  ; delay register MID byte
> DelayH  equ 0x0E  ; delay register HIGH byte

MPLAB comes with include files for each processor.  Use them.

There is no advantage to defining PORTA, STATUS, etc yourself.  At best you
won't mess it up, which gets you the same values that are in the include
file.

{Quote hidden}

Are you trying to put a comment behind every line because you're "supposed
to"?  Comments that just expand the opcodes in words are useless.  Try
explaining the higher purpose of each line.  Assume whoever is reading your
assembly code knows how to read assembly code.  For example:

   clrf  delayl   ;init inner loop counter
   clrf  delaym   ;init middle loop counter
   movlw 3h       ;init outer loop counter
   movwf delayh

> Wait1  decfsz DelayL  ; subtract 1 from DelayL
>   goto Wait1  ; if not 0, goto Wait1
>   decfsz DelayM  ; subtract 1 from DelayM
>   goto Wait1  ; if not 0, goto Wait1
>   decfsz DelayH  ; subtract 1 from DelayH
>   goto Wait1  ; if not 0, goto Wait1
>   return   ; finished the delay
>
>   end

This sort of simple routine can be easily debugged with the simulator.  Does
it work correctly there?


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, spam_OUTolinTakeThisOuTspamembedinc.com, http://www.embedinc.com

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\03\28@151018 by Stephen Wrobleski

flavicon
face
Just a quick idea, but what happens if you hook the LED up to power (through
a resistor of course), or leave your PIC pin on? Could it be a flashing LED?
It doesn't seem like incomplex code could generate a pattern you describe.

Steve

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\03\28@161202 by Les Johnson

flavicon
picon face
I don't see a clrwdt command anywhere. Make sure the watchdog timer is
disabled in the FUSE settings of the PIC, or add a few CLRWDT instructions
withing the loops.

Without these, the PIC with periodically reset, causing symptoms that you
describe.

And by the way, comment your own code as you see fit and in your own style.
Comments are a personal thing and do not fit in with any rules.


Regards
Les

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\03\28@165035 by Bob Blick

face
flavicon
face
Watchdog timer fuse set but you are not intending to use it?

On Wed, 28 Mar 2001, Simon Ethier wrote:

> I have a small program to flash a led, when I program it in the PIC16F84A with  my P16PRO programmer, the LED is flashing BUT,  it ain't flashing as it is supposed to. Instead of bein "on" for 500ms (or so) and then shut off for another 500ms(or so), and then start this forever, the LED do this :
>
> it goes on for about 500ms, then shut off for another 500ms, then in a 500ms laps time it does this :  it goes on for I'd say150ms, goes off for 150ms, then goes on for 150ms. After this, it starts again :  goes off for 500ms,  goes on for 150ms, off 150ms, etc...
>
> So it seems the time it is supposed to be "on" for 500ms, in that period of time  it goes on, off, on
>
> Anyone has an explanation for this ?
> (I hope your were able to figure out what it is doing .... hehe)

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\03\28@181700 by Tony Nixon

flavicon
picon face
Olin Lathrop wrote:


> MPLAB comes with include files for each processor.  Use them.
>
> There is no advantage to defining PORTA, STATUS, etc yourself.  At best you
> won't mess it up, which gets you the same values that are in the include
> file.


Hi Olin,

This was part of a series of start up programs for people who don't know
what an include file is yet.

Further along, the code samples offer more explanation and begin to
dispense with that syntax and use the include files instead and slowly
move into some of the innards of MPLAB.

I understand the code looks trivial to most, but I have had positive
feedback on most of it.

--
Best regards

Tony

mICro's
http://www.picnpoke.com
.....salesKILLspamspam@spam@picnpoke.com

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\03\28@185955 by Bob Ammerman

picon face
Maybe the Watchdog is going off?

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)

{Original Message removed}

2001\03\28@203216 by Simon Ethier

flavicon
face
Actually I didn't wrote that code and comment ... I took it from a file
someone sent me...

----- Original Message -----
From: "Olin Lathrop" <olin_piclistspamKILLspamEMBEDINC.COM>
To: <.....PICLISTKILLspamspam.....MITVMA.MIT.EDU>
Sent: Wednesday, March 28, 2001 2:11 PM
Subject: Re: [PIC]: Flashing a LED


{Quote hidden}

you
{Quote hidden}

your
{Quote hidden}

Does
{Quote hidden}

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\03\28@203244 by Simon Ethier

flavicon
face
Yes it works correctly in the simulator ...

----- Original Message -----
From: "Olin Lathrop" <olin_piclistspamspam_OUTEMBEDINC.COM>
To: <@spam@PICLISTKILLspamspamMITVMA.MIT.EDU>
Sent: Wednesday, March 28, 2001 2:11 PM
Subject: Re: [PIC]: Flashing a LED


{Quote hidden}

you
{Quote hidden}

your
{Quote hidden}

Does
{Quote hidden}

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\03\28@204132 by Simon Ethier

flavicon
face
Well I like it very much :)

----- Original Message -----
From: "Tony Nixon" <RemoveMETony.NixonTakeThisOuTspamENG.MONASH.EDU.AU>
To: <spamBeGonePICLISTspamBeGonespamMITVMA.MIT.EDU>
Sent: Wednesday, March 28, 2001 6:15 PM
Subject: Re: [PIC]: Flashing a LED


> Olin Lathrop wrote:
>
>
> > MPLAB comes with include files for each processor.  Use them.
> >
> > There is no advantage to defining PORTA, STATUS, etc yourself.  At best
you
{Quote hidden}

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\03\28@210447 by Olin Lathrop

face picon face
> And by the way, comment your own code as you see fit and in your own
style.
> Comments are a personal thing and do not fit in with any rules.

True, there are no rules on how you MUST comment your code.  However, there
are certainly right and wrong ways to comment your code if you wish to do it
well.


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, RemoveMEolinspamTakeThisOuTembedinc.com, http://www.embedinc.com

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\03\29@034942 by Alan B. Pearce

face picon face
> This was part of a series of start up programs for people who don't know
> what an include file is yet.

I would have thought that one of the first things to do would be to teach them
about the include file and how it helps them in their coding.

This is not meant as a sarcastic comment on the teaching style of your course,
but rather a comment of how I see the pupils having good pointers early on which
would help them understand how the target processor itself works, and how the
assembler does pre-processor things for them.

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2001\03\29@174645 by Tony Nixon

flavicon
picon face
"Alan B. Pearce" wrote:
>
> > This was part of a series of start up programs for people who don't know
> > what an include file is yet.
>
> I would have thought that one of the first things to do would be to teach them
> about the include file and how it helps them in their coding.
>
> This is not meant as a sarcastic comment on the teaching style of your course,
> but rather a comment of how I see the pupils having good pointers early on which
> would help them understand how the target processor itself works, and how the
> assembler does pre-processor things for them.
>

That's fine I guess, but if newcomers don't even understand what MOVLW
means how are they going to comprehend an include file.

This is the first program that I mention and that is after 16 pages of
lead up explanantion starting with 0 and 1. This simple program gets
explained in detail and then how to write it in Mnemonic format etc.
etc... and on it goes. They can then click on a link on the page and
start the animated simulator and watch each of these simple instructions
execute and get a visual idea of what is happening inside the processor.


       Title "mICro’s Simple Program"

       list p=16f84 ; processor type
;
; -------------
; PROGRAM START
; -------------
;
       org 0h                ; startup address = 0000

start        movlw 0x00        ; simple code
       movwf 0x05
       goto start        ; do this loop forever

       end

Its' similar to the clock project on my page. It provides a PDF file, 17
source code files, watch files etc. that build the project up from
scratch and explain why each part is added and also how to simulate the
files. There are also a few of these asm files with little bugs in them
to spark up some problem solving when things don't work as expected.

Teaching is certainly an art and I'm definitely no expert, but you have
to start somewhere :-)

-- Best regards

Tony

mICro's
http://www.picnpoke.com
salesEraseMEspam.....picnpoke.com

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2001\03\29@184539 by Olin Lathrop

face picon face
> That's fine I guess, but if newcomers don't even understand what MOVLW
> means how are they going to comprehend an include file.

Because include files are pretty universal regardless of what you are
programming and what language you are using.  MOVLW on the other hand is
unique to the PICs.  Presumably you are not trying to teach PIC programming
to someone who knows nothing about programming in general!?



********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, EraseMEolinspamembedinc.com, http://www.embedinc.com

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2001\03\29@185343 by Tony Nixon

flavicon
picon face
Olin Lathrop wrote:
>
> > That's fine I guess, but if newcomers don't even understand what MOVLW
> > means how are they going to comprehend an include file.
>
> Because include files are pretty universal regardless of what you are
> programming and what language you are using.  MOVLW on the other hand is
> unique to the PICs.  Presumably you are not trying to teach PIC programming
> to someone who knows nothing about programming in general!?


Yes, that was the general idea.

--
Best regards

Tony

mICro's
http://www.picnpoke.com
RemoveMEsalesEraseMEspamEraseMEpicnpoke.com

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2001\03\29@193554 by Bill Westfield

face picon face
   > That's fine I guess, but if newcomers don't even understand what MOVLW
   > means how are they going to comprehend an include file.

Hmm.  I vaguely remember getting taught some programming languages and
systems that included "magic" that I was expected to use without
understanding, at least for quite some time into the class.  Come to think
of it, IBM JCL in an actual business environment was handled pretty close
to that way - if you needed some jcl, you talked to the "systems
programmers."  I don't know whether I consider this a great idea or not.
On the one hand, using the includes lets you use the appropriate names for
things (as used in the datasheets/etc.)  On the other hand, defining the
constants yourself teaches you useful things about what and where the
"special registers actually are.


   Because include files are pretty universal regardless of what you are
   programming and what language you are using.

Um, not.  C based languages are the only ones I can think of offhand that
has a strong reliance on include files.  Fortran, Pascal, Cobol, PL/1, APL,
Basic: Nope.  Assemblers run about 50/50 - many assemblers predefine the
most common symbols for you (where there isn't as much variation between
different things with the same assembler), and only use include files for
"advanced" macro definitions.


   Presumably you are not trying to teach PIC
   programming to someone who knows nothing about programming in general!?

It'd be pretty desirable to teach PIC assembler to people whose previous
experience was all in BASIC (ie STAMPs, etc)...

BillW

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2001\03\29@214052 by Dale Botkin

flavicon
face
On Thu, 29 Mar 2001, Olin Lathrop wrote:

> > That's fine I guess, but if newcomers don't even understand what MOVLW
> > means how are they going to comprehend an include file.
>
> Because include files are pretty universal regardless of what you are
> programming and what language you are using.  MOVLW on the other hand is
> unique to the PICs.  Presumably you are not trying to teach PIC programming
> to someone who knows nothing about programming in general!?

Why not?  It's as good a place as any to start.

Dale
---
The most exciting phrase to hear in science, the one that heralds new
discoveries, is not "Eureka!" (I found it!) but "That's funny ..."
               -- Isaac Asimov

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2001\03\30@015840 by Justin Fielding

flavicon
face
I understand MOVLW to mean, Move the Literal value (specified after the
instruction) into the W register.. Is this not correct?



{Original Message removed}

2001\03\30@024828 by Tony Nixon

flavicon
picon face
Justin Fielding wrote:
>
> I understand MOVLW to mean, Move the Literal value (specified after the
> instruction) into the W register.. Is this not correct?

No, it is correct :-)

--
Best regards

Tony

mICro's
http://www.bubblesoftonline.com
RemoveMEsalesspam_OUTspamKILLspampicnpoke.com

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


2001\03\30@025706 by Justin Fielding

flavicon
face
Good, had me worried there.

Jusitn.

----- Original Message -----
From: "Tony Nixon" <RemoveMETony.NixonTakeThisOuTspamspamENG.MONASH.EDU.AU>
To: <EraseMEPICLISTspamspamspamBeGoneMITVMA.MIT.EDU>
Sent: Friday, March 30, 2001 8:04 AM
Subject: Re: [PIC]: Flashing a LED


{Quote hidden}

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


2001\03\30@080353 by Olin Lathrop

face picon face
> Um, not.  C based languages are the only ones I can think of offhand that
> has a strong reliance on include files.  Fortran, Pascal, Cobol, PL/1,
APL,
> Basic: Nope.

Of the languages you mention, I've done a lot of programming in Fortran and
Pascal, and some Basic and a little bit of PL/1.  All the Fortran I did
since the mid 1970s heavily relied on include files.  I've done Pascal since
about 1980 and still use variants of it today, and all of it heavily uses
include files.  Modern Basic, in fact just about any MODERN language, uses
include files.  I've used a lot of different assemblers, and can't remember
a single one that didn't have include file capability.


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, olinSTOPspamspamspam_OUTembedinc.com, http://www.embedinc.com

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


2001\03\30@080403 by Olin Lathrop

face picon face
> I understand MOVLW to mean, Move the Literal value (specified after the
> instruction) into the W register.. Is this not correct?

Yup, correct.  All the instruction are explained in the "Instruction Set
Summary" section of the data sheet.  For my 16F87x data sheet, this is
section 13.0 starting on page 137.


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, spamBeGoneolinSTOPspamspamEraseMEembedinc.com, http://www.embedinc.com

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


2001\03\30@082856 by Bob Ammerman

picon face
> > Um, not.  C based languages are the only ones I can think of offhand
that
> > has a strong reliance on include files.  Fortran, Pascal, Cobol, PL/1,
> APL,
> > Basic: Nope.
>
> Of the languages you mention, I've done a lot of programming in Fortran
and
> Pascal, and some Basic and a little bit of PL/1.  All the Fortran I did
> since the mid 1970s heavily relied on include files.  I've done Pascal
since
> about 1980 and still use variants of it today, and all of it heavily uses
> include files.  Modern Basic, in fact just about any MODERN language, uses
> include files.  I've used a lot of different assemblers, and can't
remember
> a single one that didn't have include file capability.
>
>
> ********************************************************************
> Olin Lathrop, embedded systems consultant in Littleton Massachusetts


Au contraire....

The early Fortran standards did not include include files (tho' many
implemenations supported them).

JAVA doesn't use them.

Turbo Pascal doesn't need them (it uses UNITs instead).

Many VB programmers never use them.

Many assembly language programs don't use/need them (tho' most assemblers
support them).

In short, include files are hardly a universal thing.

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


2001\03\30@083303 by Spehro Pefhany

picon face
At 08:22 AM 3/30/01 -0500, you wrote:
>Au contraire....
>The early Fortran standards did not include include files (tho' many
>implemenations supported them).
>JAVA doesn't use them.
...
>In short, include files are hardly a universal thing.

Yes, I had to write a little .awk preprocessor to get Postscript
(one of the more modern languages) to use include files. ;-)

Best regards,

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Spehro Pefhany --"it's the network..."            "The Journey is the reward"
KILLspamspeffspamBeGonespaminterlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
Contributions invited->The AVR-gcc FAQ is at: http://www.bluecollarlinux.com
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.



'[PIC]: Flashing a LED'
2001\04\01@112647 by mervin
flavicon
face
Yesterday I was thumbing through my Poplar Sci mag and ran across an ad for
a radar scrambler type device.
Now I don't advocate driving at excessive speeds but one of the features of
the device seemed like a good PIC project.

They used a flashing IR LED to confuse the LASER type speed guns. The add
said the laser gun takes several readings per second of the object that its
pointed at and measures the difference for a mph. The IR LED flashing
confuses the laser's computer and no speed registers at the gun display.

Does anyone know anything about how this works?
Would the IRLED have to flash at a particular freq, if so what?

Thanks
Malcolm

--
http://www.piclist.com hint: To leave the PICList
EraseMEpiclist-unsubscribe-requestspamEraseMEmitvma.mit.edu


2001\04\01@180450 by Olin Lathrop

face picon face
> They used a flashing IR LED to confuse the LASER type speed guns. The add
> said the laser gun takes several readings per second of the object that
its
> pointed at and measures the difference for a mph. The IR LED flashing
> confuses the laser's computer and no speed registers at the gun display.
>
> Does anyone know anything about how this works?
> Would the IRLED have to flash at a particular freq, if so what?

I not familiar with the exact design of radar speed guns, but I find it hard
to believe that pulsing IR of such low power would have any effect at all.
Radar uses microwaves which have wavelengths of several millimeters.  IR
LEDs usually have wavelengths below 1 micrometer.  There must be much more
IR power at longer wavelengths than that emitted by the hot radiator.

Did they give any reason why a pulsing IR LED should confuse the radar gun?


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, @spam@olin@spam@spamspam_OUTembedinc.com, http://www.embedinc.com

--
http://www.piclist.com hint: To leave the PICList
spamBeGonepiclist-unsubscribe-requestspamKILLspammitvma.mit.edu


2001\04\01@180913 by Steven J. Devine

flavicon
face
> Did they give any reason why a pulsing IR LED should confuse the radar
gun?

This will not confuse RADAR, but it WILL confuse the newer laser-based
systems which utilize IR lasers (don't know anything beyond this tho).

--
http://www.piclist.com hint: To leave the PICList
.....piclist-unsubscribe-requestspam_OUTspammitvma.mit.edu


2001\04\01@181117 by Bob Ammerman

picon face
> > They used a flashing IR LED to confuse the LASER type speed guns. The
add
> > said the laser gun takes several readings per second of the object that
> its
> > pointed at and measures the difference for a mph. The IR LED flashing
> > confuses the laser's computer and no speed registers at the gun display.
> >
> > Does anyone know anything about how this works?
> > Would the IRLED have to flash at a particular freq, if so what?
>
> I not familiar with the exact design of radar speed guns, but I find it
hard
> to believe that pulsing IR of such low power would have any effect at all.
> Radar uses microwaves which have wavelengths of several millimeters.  IR
> LEDs usually have wavelengths below 1 micrometer.  There must be much more
> IR power at longer wavelengths than that emitted by the hot radiator.
>
> Did they give any reason why a pulsing IR LED should confuse the radar
gun?

Because it isn't a radar gun, but rather a LASER type speed gun, as the
poster said.

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)

--
http://www.piclist.com hint: To leave the PICList
TakeThisOuTpiclist-unsubscribe-request.....spamTakeThisOuTmitvma.mit.edu


2001\04\01@192956 by Steve Bergerson

flavicon
face
Laser not Radar....

I could believe that a small low power laser flashes at the right frequency
as the one in the police car might work.  But you would have to use the same
wavelength laser as is used in theirs.  I really have no idea what that
would be.

Also Trying to evade a laser detector and driving above the speed limit is
not too bright anyway.  Always obey the rules of the road.


From Steve

Not all heroes wear tights and a cape.
In theory, there is no difference between theory and practice, but in
practice there is a great deal of difference.


TakeThisOuTdbergerKILLspamspamspamoptonline.com
{Original Message removed}

2001\04\02@094741 by Thomas C. Sefranek

face picon face
Olin Lathrop wrote:

> > They used a flashing IR LED to confuse the LASER type speed guns. The add
> > said the laser gun takes several readings per second of the object that its
> > pointed at and measures the difference for a mph. The IR LED flashing
> > confuses the laser's computer and no speed registers at the gun display.
>
>
> Did they give any reason why a pulsing IR LED should confuse the radar gun?

It's MY turn Olin...

A LASER speed gun is a LIGHT measuring device, not radio radar gun.
(Sometime even YOU can miss the obvious...)

--
 *
 |  __O    Thomas C. Sefranek  .....tcsspamRemoveMEcmcorp.com
 |_-\<,_   Amateur Radio Operator: WA1RHP
 (*)/ (*)  Bicycle mobile on 145.41, 448.625 MHz

ARRL Instructor, Technical Specialist, VE Contact.
hamradio.cmcorp.com/inventory/Inventory.html
http://www.harvardrepeater.org

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\04\02@131441 by Chris Carr

flavicon
face
Just to throw in my 2 groats worth

Radar - originally stood for RAdio Direction And Ranging.

The laser equivalent being

Lidar - Light Direction And Ranging.

Perhaps we should coin a new word like

Eledar - ELEctromagnetic Direction And Ranging

Then we could have Radio Eledar, Laser Eledar or Ultrasonic Eledar.

Hmmmm, methinks there could be a flaw in this idea

8-)

Chris

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\04\02@132226 by Chris Carr

flavicon
face
Just to throw in my 2 groats worth

 Radar - originally stood for RAdio Direction And Ranging.

The laser equivalent being

Lidar - Light Direction And Ranging.

Perhaps we should coin a new word like

Eledar - ELEctromagnetic Direction And Ranging

Then we could have Radio Eledar, Laser Eledar or Ultrasonic Eledar.

Hmmmm, methinks there could be a flaw in this idea

8-)

Chris
(just cocked up the subject line format again, sorry James)

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\04\02@134701 by Bob Ammerman

picon face
----- Original Message -----
From: Chris Carr <RemoveMEnyedspamspamBeGoneBTINTERNET.COM>
To: <spamBeGonePICLIST@spam@spamspam_OUTMITVMA.MIT.EDU>
Sent: Monday, April 02, 2001 1:10 PM
Subject: Re: [PIC]: Flashing a LED


{Quote hidden}

Yeah, Ultrasonic isn't emag.

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\04\02@170357 by Nick Ray

flavicon
picon face
> -----Original Message-----
> From: pic microcontroller discussion list
> [TakeThisOuTPICLISTspamspamMITVMA.MIT.EDU]On Behalf Of Thomas C. Sefranek
> Sent: 02 April 2001 14:47
> To: PICLISTEraseMEspamMITVMA.MIT.EDU
> Subject: Re: [PIC]: Flashing a LED
> >
> > Did they give any reason why a pulsing IR LED should confuse
> the radar gun?
>
> It's MY turn Olin...
>
> A LASER speed gun is a LIGHT measuring device, not radio radar gun.
> (Sometime even YOU can miss the obvious...)
>

Well, one could argue that light IS radio I suppose :)

Not sure though why a LED would interfere with a coherent light source
anyway...

- Nick

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\04\02@203029 by mervin

flavicon
face
Here is a link to the ad I saw from technoscout.com, the unit is called the
Phazer.

www.comtrad.com/cfusion/template/makepage.cfm?prod_name=Phazer_Radar&
site=85171&branch=unshocked&category=0&product_base_id=61&sourceid=003506547
92966396729

I thought I posted this last night but I guess I sent it to an individual
instead, sorry.

Malcolm

{Original Message removed}

More... (looser matching)
- Last day of these posts
- In 2001 , 2002 only
- Today
- New search...