Post by thread:[PIC] Increasing LED Intensity.

Hi all. I have just completed a "prototype" project (hobby), that is an Infra-Red remote control for a Nikon D70s camera. The primary motivation is to create an "extended range" relative to the remote that Nikon sells (I set the camera on a tripod, focussed on a bird feeder. I want to be really far away and still trigger the camera... maybe even set up a motion detector ... ;-). Right now it is working, but it's range is "only on par" with the Nikon remote (and a lot more clunky ;-). I have a bunch of IR LED's available. They are 100ma with 1V volt drop. They have a 20deg "half-intensity" beam angle. I am using 2 AAA cells to power the system (nominal 3V). Because the IR Signal is a 40KHz 50% duty cycle when on, and for each "trigger" it will only be on (at 40KHz) for 8ms for the complete trigger sequence of 85ms, I believe I could exceed the 100mA "continuous" rating. It's "pulse" rating is something like 10A for a few uSec. I am using a 16F628A with INTOSC@4MHz To Drain the current of 100mA, I am using 4 PORTB pins as a sink (25mA current per pin as per datasheet). My calculations indicate that to get 100ma through the LED with 1V forward, and 3V system, I need 20Ohm resistance. To sink that through 4 pins, I connected an 82 Ohm resistor to each pin, and then the LED through the 4 parallel resistors, giving a net parallel resistance of about 20Ohm. Now, for my questions..... 1.) How do I get better range on the IR remote? Options I have considered....: i) Drive the IR-LED at more than 100mA (add another PORTB Pin to sink current to?) If so, how High can I go? ii) Add another IR-LED (either in parallel with first? or as a seperate system entirely?) iii) Get a "brighter" IR-LED? iv) Add another AAA cell, run the system at 4.5V? v) Get a "narrower beam" IR-LED. Which avenue holds the most promise? Is there an option I have not considered? 2) What is the math for 2 LED's in parallel....? To get 100mA through each LED I'd need to sink 200mA. Probaby use an external transistor for that.... not PIC Pins. Would it be better to use 2x20 Ohm resistance one for each LED, or could I use a single 10 Ohm resistance common to both LED's? 3) Why does it not work well at "close range" < 6inches or so from Camera. Is it possible to "flood" an IR receiver? I know that I have given a lot of detail. Hopefully someone with more experience than me at "real-world" electronics can bring their experience to bear on my challenge... ;-) Thanks in advance. Rolf

On Sat, Oct 22, 2005 at 02:46:38PM -0400, Rolf wrote: > Hi all. > > I have just completed a "prototype" project (hobby), that is an > Infra-Red remote control for a Nikon D70s camera. The primary motivation > is to create an "extended range" relative to the remote that Nikon sells > (I set the camera on a tripod, focussed on a bird feeder. I want to be > really far away and still trigger the camera... maybe even set up a > motion detector ... ;-). > > Right now it is working, but it's range is "only on par" with the Nikon > remote (and a lot more clunky ;-). Since you already have your remote working, I think the best thing you could do is to install a system of lenses either on the remote or in front of the IR receiver on the camara. This way you won't have to modify your circuit. You didn't say how far away you want to use the remote, but there is going to be a distance where using lenses is the only reasonable solution. Good luck. Matthew -- "Protecting the children is a good way to get a lot of adults who can't stand up for themselves" -- J. Stecher

At 02:46 PM 10/22/2005 -0400, you wrote: {Quote hidden}>Hi all. > >I have just completed a "prototype" project (hobby), that is an Infra-Red >remote control for a Nikon D70s camera. The primary motivation is to >create an "extended range" relative to the remote that Nikon sells (I set >the camera on a tripod, focussed on a bird feeder. I want to be really far >away and still trigger the camera... maybe even set up a motion detector >... ;-). > >Right now it is working, but it's range is "only on par" with the Nikon >remote (and a lot more clunky ;-). > >I have a bunch of IR LED's available. They are 100ma with 1V volt drop. >They have a 20deg "half-intensity" beam angle. I am using 2 AAA cells to >power the system (nominal 3V). >Because the IR Signal is a 40KHz 50% duty cycle when on, and for each >"trigger" it will only be on (at 40KHz) for 8ms for the complete trigger >sequence of 85ms, I believe I could exceed the 100mA "continuous" rating. >It's "pulse" rating is something like 10A for a few uSec. > >I am using a 16F628A with INTOSC@4MHz > >To Drain the current of 100mA, I am using 4 PORTB pins as a sink (25mA >current per pin as per datasheet). My calculations indicate that to get >100ma through the LED with 1V forward, and 3V system, I need 20Ohm >resistance. To sink that through 4 pins, I connected an 82 Ohm resistor to >each pin, and then the LED through the 4 parallel resistors, giving a net >parallel resistance of about 20Ohm. Have you put an oscilloscope across any of the resistors to see what current you are actually getting? I suspect a lot less than 100mA total, both because of the PIC at such a low power supply voltage and because I suspect the voltage drop of the IRLED is a fair bit greater than 1V at anything like 100mA. You should probably use a very low voltage MOSFET (eg. Zetex ZXMN2A02N8, which has 40mohm Rds(on) at Vgs=2.5V) or a bipolar (eg. Sziklai pair-- cheaper) to drive the LEDs, with a single port pin. After you get it working at ~100mA (assuming your LED is actually rated to work at that current) you can re-evaluate the range and see if you need to do anything more. If you do decide to use more than one LED, it's best to use a separate resistor for each to ensure that the current splits more evenly. Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" spam_OUTspeffTakeThisOuTinterlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com ->> Inexpensive test equipment & parts http://search.ebay.com/_W0QQsassZspeff

I wish I had an Oscilloscope ... Anyone selling one cheap? I have the specs on the LED and they are rated at 100mA continuous. The circuit is simple, and mounted on a "sea-of-holes" just 7 x 20 with room to spare... 6 resistors + 1 F628A. There is no circuit board (and will never be). I have lots of space to solder/desolder. My biggest issue is that I am unfamiliar with the parts available... I have to learn what a Sziklai pair is, and if my (small) local electronics store has it. I have no training in real electronics... I am a computer programmer doing this "for fun". I have interest, but no experience.... I do have an opto-coupler on hand (excess from another "learning" project), and that will probably do the trick... worth a try (I was planning on using it to drive multiple LED's at 100mA each). I believe the switching time would be fine. Need to (re-)read the specs on it though. I am hoping for a range greater than 20 meters ( 50' ). Thanks for a new avenue of research... Rolf Spehro Pefhany wrote: {Quote hidden}> At 02:46 PM 10/22/2005 -0400, you wrote: > >> Hi all. >> >> I have just completed a "prototype" project (hobby), that is an >> Infra-Red remote control for a Nikon D70s camera. The primary >> motivation is to create an "extended range" relative to the remote >> that Nikon sells (I set the camera on a tripod, focussed on a bird >> feeder. I want to be really far away and still trigger the camera... >> maybe even set up a motion detector ... ;-). >> >> Right now it is working, but it's range is "only on par" with the >> Nikon remote (and a lot more clunky ;-). >> >> I have a bunch of IR LED's available. They are 100ma with 1V volt >> drop. They have a 20deg "half-intensity" beam angle. I am using 2 AAA >> cells to power the system (nominal 3V). >> Because the IR Signal is a 40KHz 50% duty cycle when on, and for each >> "trigger" it will only be on (at 40KHz) for 8ms for the complete >> trigger sequence of 85ms, I believe I could exceed the 100mA >> "continuous" rating. It's "pulse" rating is something like 10A for a >> few uSec. >> >> I am using a 16F628A with INTOSC@4MHz >> >> To Drain the current of 100mA, I am using 4 PORTB pins as a sink >> (25mA current per pin as per datasheet). My calculations indicate >> that to get 100ma through the LED with 1V forward, and 3V system, I >> need 20Ohm resistance. To sink that through 4 pins, I connected an 82 >> Ohm resistor to each pin, and then the LED through the 4 parallel >> resistors, giving a net parallel resistance of about 20Ohm. > > > Have you put an oscilloscope across any of the resistors to see what > current you are > actually getting? I suspect a lot less than 100mA total, both because > of the PIC at > such a low power supply voltage and because I suspect the voltage drop > of the IRLED > is a fair bit greater than 1V at anything like 100mA. > > You should probably use a very low voltage MOSFET (eg. Zetex > ZXMN2A02N8, which > has 40mohm Rds(on) at Vgs=2.5V) or a bipolar (eg. Sziklai pair-- cheaper) > to drive the LEDs, with a single port pin. After you get it working > at ~100mA > (assuming your LED is actually rated to work at that current) you can > re-evaluate the range and see if you need to do anything more. > > If you do decide to use more than one LED, it's best to use a separate > resistor for each to ensure that the current splits more evenly. > > Best regards, > > Spehro Pefhany --"it's the network..." "The Journey is the > reward" > .....speffKILLspam@spam@interlog.com Info for manufacturers: > http://www.trexon.com > Embedded software/hardware/analog Info for designers: > http://www.speff.com > ->> Inexpensive test equipment & parts > http://search.ebay.com/_W0QQsassZspeff > >

You should probably be driving the LED with a transistor of some sort...FET, BJT, whatever, but multiple PIC pins isn't the best option. That'll let you kick up your drive current, which you can easily do for a pulsed LED like that. Have you filtered visible light on the receiver end? Try using the blank bits of developed film left on the negatives you get back from the photomat. That stops a lot of visible light but is quite transparent to IR. 20 meters should be quite possible. I see remotes that work across 10 on a daily basis, no problem. Mike H.

Hi all, and thanks for the assistance. IR Remote now has about 30+ meter range (at night, +- 3deg celcius), at least twice the range of the Nikon remote (same conditions). For the record. I upgraded to 9V battery with an LM78L05 for the PIC (9V through the IR LED's). Used 2 IR LEDs, with them both being driven at very high current (1V forward voltage on LED, 9V nominal, 20Ohm resistance = 400mA through each LED (very short pulses though). Rated at 100mA continuous. These are being driven by BS170 MOSFET by a 12F675 My first complete "real" project. Takes bow.... Now, I have just one question, somewhat off topic.... Anyone know how to "broaden" the reception of an IR Receiver. The D70 seems to have a very "directional" receiver. More than about 15 degrees either side of where the lens is pointing, and the receiver does not activate (for neither my remote, nor the Nikon one...). I am reluctant to open the camera (will not happen), but I am open to suggestions of putting some lens or something to accomplish the broadening. Thanks Rolf Rolf wrote: {Quote hidden}> Hi all. > > I have just completed a "prototype" project (hobby), that is an > Infra-Red remote control for a Nikon D70s camera. The primary > motivation is to create an "extended range" relative to the remote > that Nikon sells (I set the camera on a tripod, focussed on a bird > feeder. I want to be really far away and still trigger the camera... > maybe even set up a motion detector ... ;-). > > Right now it is working, but it's range is "only on par" with the > Nikon remote (and a lot more clunky ;-). > > I have a bunch of IR LED's available. They are 100ma with 1V volt > drop. They have a 20deg "half-intensity" beam angle. I am using 2 AAA > cells to power the system (nominal 3V). > Because the IR Signal is a 40KHz 50% duty cycle when on, and for each > "trigger" it will only be on (at 40KHz) for 8ms for the complete > trigger sequence of 85ms, I believe I could exceed the 100mA > "continuous" rating. It's "pulse" rating is something like 10A for a > few uSec. > > I am using a 16F628A with INTOSC@4MHz > > To Drain the current of 100mA, I am using 4 PORTB pins as a sink (25mA > current per pin as per datasheet). My calculations indicate that to > get 100ma through the LED with 1V forward, and 3V system, I need 20Ohm > resistance. To sink that through 4 pins, I connected an 82 Ohm > resistor to each pin, and then the LED through the 4 parallel > resistors, giving a net parallel resistance of about 20Ohm. > > Now, for my questions..... > > 1.) How do I get better range on the IR remote? > > Options I have considered....: > i) Drive the IR-LED at more than 100mA (add another PORTB Pin to > sink current to?) If so, how High can I go? > ii) Add another IR-LED (either in parallel with first? or as a > seperate system entirely?) > iii) Get a "brighter" IR-LED? > iv) Add another AAA cell, run the system at 4.5V? > v) Get a "narrower beam" IR-LED. > > Which avenue holds the most promise? Is there an option I have not > considered? > > 2) What is the math for 2 LED's in parallel....? To get 100mA through > each LED I'd need to sink 200mA. Probaby use an external transistor > for that.... not PIC Pins. Would it be better to use 2x20 Ohm > resistance one for each LED, or could I use a single 10 Ohm resistance > common to both LED's? > > 3) Why does it not work well at "close range" < 6inches or so from > Camera. Is it possible to "flood" an IR receiver? > > I know that I have given a lot of detail. Hopefully someone with more > experience than me at "real-world" electronics can bring their > experience to bear on my challenge... ;-) > > Thanks in advance. > > Rolf

At 11:15 PM 10/27/2005 -0400, you wrote: >Hi all, and thanks for the assistance. > >IR Remote now has about 30+ meter range (at night, +- 3deg celcius), at >least twice the range of the Nikon remote (same conditions). Are you planning on writing this up? I happen to have a D70 as well and have not gotten the remote yet. {Quote hidden}>For the record. I upgraded to 9V battery with an LM78L05 for the PIC (9V >through the IR LED's). Used 2 IR LEDs, with them both being driven at very >high current (1V forward voltage on LED, 9V nominal, 20Ohm resistance = >400mA through each LED (very short pulses though). Rated at 100mA >continuous. These are being driven by BS170 MOSFET by a 12F675 > >My first complete "real" project. > >Takes bow.... > >Now, I have just one question, somewhat off topic.... > >Anyone know how to "broaden" the reception of an IR Receiver. The D70 >seems to have a very "directional" receiver. More than about 15 degrees >either side of where the lens is pointing, and the receiver does not >activate (for neither my remote, nor the Nikon one...). I am reluctant to >open the camera (will not happen), but I am open to suggestions of putting >some lens or something to accomplish the broadening. What about a Fresnel lens or diffuser in front of the receiver lens? You could try a bit of frosted or pebbled clear plastic. A Fresnel lens out of a duff motion detector etc. How about scuffing up a bit of clear sticky tape with emery paper and sticking it over the receiver? Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" speffKILLspaminterlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com ->> Inexpensive test equipment & parts http://search.ebay.com/_W0QQsassZspeff

Clear polyethylene diffuser will broader the detector angle. Penalty is lower sensitivity. You could also use ping pong ball material, but it has significant attenuation. You basically want to put something in front of the detector that will catch rays from farther off axis and put them where the detector will see them. I use dull side of aluminum foil on my stereo gear so I can hit it from my office at 80 degree angle. Rolf wrote: > Hi all, and thanks for the assistance. > > IR Remote now has about 30+ meter range (at night, +- 3deg celcius), at > least twice the range of the Nikon remote (same conditions). You could also have modified the Nikon remote to drive it's LED harder. They underdrive it to get good battery life so dropping the LED series R would get you more range. {Quote hidden}> For the record. I upgraded to 9V battery with an LM78L05 for the PIC (9V > through the IR LED's). Used 2 IR LEDs, with them both being driven at > very high current (1V forward voltage on LED, 9V nominal, 20Ohm > resistance = 400mA through each LED (very short pulses though). Rated at > 100mA continuous. These are being driven by BS170 MOSFET by a 12F675 > > My first complete "real" project. > > Takes bow.... > > Now, I have just one question, somewhat off topic.... > > Anyone know how to "broaden" the reception of an IR Receiver. The D70 > seems to have a very "directional" receiver. More than about 15 degrees > either side of where the lens is pointing, and the receiver does not > activate (for neither my remote, nor the Nikon one...). I am reluctant > to open the camera (will not happen), but I am open to suggestions of > putting some lens or something to accomplish the broadening. > > Thanks > > Rolf > > > Rolf wrote: > >> Hi all. >> >> I have just completed a "prototype" project (hobby), that is an >> Infra-Red remote control for a Nikon D70s camera. The primary >> motivation is to create an "extended range" relative to the remote >> that Nikon sells (I set the camera on a tripod, focussed on a bird >> feeder. I want to be really far away and still trigger the camera... >> maybe even set up a motion detector ... ;-). >> >> Right now it is working, but it's range is "only on par" with the >> Nikon remote (and a lot more clunky ;-). >> >> I have a bunch of IR LED's available. They are 100ma with 1V volt >> drop. They have a 20deg "half-intensity" beam angle. I am using 2 AAA >> cells to power the system (nominal 3V). >> Because the IR Signal is a 40KHz 50% duty cycle when on, and for each >> "trigger" it will only be on (at 40KHz) for 8ms for the complete >> trigger sequence of 85ms, I believe I could exceed the 100mA >> "continuous" rating. It's "pulse" rating is something like 10A for a >> few uSec. >> >> I am using a 16F628A with INTOSC@4MHz >> >> To Drain the current of 100mA, I am using 4 PORTB pins as a sink (25mA >> current per pin as per datasheet). My calculations indicate that to >> get 100ma through the LED with 1V forward, and 3V system, I need 20Ohm >> resistance. To sink that through 4 pins, I connected an 82 Ohm >> resistor to each pin, and then the LED through the 4 parallel >> resistors, giving a net parallel resistance of about 20Ohm. >> >> Now, for my questions..... >> >> 1.) How do I get better range on the IR remote? >> >> Options I have considered....: >> i) Drive the IR-LED at more than 100mA (add another PORTB Pin to >> sink current to?) If so, how High can I go? >> ii) Add another IR-LED (either in parallel with first? or as a >> seperate system entirely?) >> iii) Get a "brighter" IR-LED? >> iv) Add another AAA cell, run the system at 4.5V? >> v) Get a "narrower beam" IR-LED. >> >> Which avenue holds the most promise? Is there an option I have not >> considered? >> >> 2) What is the math for 2 LED's in parallel....? To get 100mA through >> each LED I'd need to sink 200mA. Probaby use an external transistor >> for that.... not PIC Pins. Would it be better to use 2x20 Ohm >> resistance one for each LED, or could I use a single 10 Ohm resistance >> common to both LED's? >> >> 3) Why does it not work well at "close range" < 6inches or so from >> Camera. Is it possible to "flood" an IR receiver? >> >> I know that I have given a lot of detail. Hopefully someone with more >> experience than me at "real-world" electronics can bring their >> experience to bear on my challenge... ;-) >> >> Thanks in advance. >> >> Rolf > > >

Spehro Pefhany wrote: > At 11:15 PM 10/27/2005 -0400, you wrote: > What about a Fresnel lens or diffuser in front of the receiver lens? > > You could try a bit of frosted or pebbled clear plastic. A Fresnel > lens out of a duff motion detector etc. How about scuffing up a bit of > clear sticky tape with emery paper and sticking it over the receiver? Or use 3M 'invisible tape' for books, which is clear and already rough. R

One thing I am not so sure is about the forward voltage drop, 1V seems to be a bit low. Normally IR LED drop is lowed than visible red LED but it is still in the range of 1.5V when pulsing at 200mA. Are you sure that it is 1V? It is possible you can pulse the IR LEDs with even higher current depending on the duty cycle and the period. To broaden the opening angle of the receiver, somehow you need to de-focus the emitter which may reduce the sensing distance. It is also possible to widen the aperture of the receiver but I think that is not an option for you since you do not want to open the D70 (not so cheap). Regards, Xiaofan {Original Message removed}

> What about a Fresnel lens or diffuser in front of the receiver lens? > > You could try a bit of frosted or pebbled clear plastic. A Fresnel > lens out of a duff motion detector etc. How about scuffing up a bit of > clear sticky tape with emery paper and sticking it over the receiver? My immediate thought was a piece of the ribbed plastic that is used in front of those pictures you used to get as a kid, where the scene changed as you changed the viewing angle. These typically had what amounts to ribs that make a fresnel lens type effect in one direction, but not in the 90 degree direction.

part 0 44 bytes his is a multi-part message in MIME format. part 1 2225 bytes content-type:text/plain; charset=ISO-8859-1; format=flowed (decoded 7bit) Thanks all... those suggestions seem easy to try... (gets out 3m "frosted" tape....) Holy ...! much better reception angle. The floor I work on is not big enough to test whether the range is reduced (presumably it is...) I got my inspiration from http://www.alanmacek.com/nikon/ who also references http://www.bigmike.it/ir-control.html You will want to look at those pages. Alan uses a 12F675 (which I use as well...). He uses the trigger momentary switch to actually turn on the power to the circuit. I chose to use the trigger as an input mechanism on an input pin instead, and have a slide switch to power the system instead. Alan's mechanism introduces a noticable delay as the Oscilator starts up, and the PIC initializes. My system has more "instant" trigger response. Additionally, Alan can only drive 25mA through the LED because he sources the current through the PIC. I have used MOSFETS to drive the LED's at about 800mA each. The general overview is: On the 12F675, there are 8 pins... in order: 1. Vdd 2. Output to trigger MOSFETs 3. Output to flash power-on LED 4. NC (Vpp - ICSP) 5. Input - pull-up resistor attached, and momentary "trigger" switch which pulls it low. 6. NC (PCLK - ICSP) 7. NC (PDAT - ICSP) 8. Vss Attached is schematic, and source code. TinyCAD does not have a "Ground" in it's standard library, so there are some "AC Symbols" instead. One other thing... the Oscillator Callibration for *my* chip is 0x74. You will have to change that value for your chip. Please all, feel free to critique my code, I would appreciate more experienced opinions... Things I know are issues so far: I use old style __CONFIG I could use more compact CycleOFF code Cheers Rolf Spehro Pefhany wrote: {Quote hidden}> At 11:15 PM 10/27/2005 -0400, you wrote: > >> Hi all, and thanks for the assistance. >> >> IR Remote now has about 30+ meter range (at night, +- 3deg celcius), >> at least twice the range of the Nikon remote (same conditions). > > > Are you planning on writing this up? I happen to have a D70 as well and > have not gotten the remote yet. > [snip] part 2 12705 bytes content-type:text/plain; (decoded 7bit) ;********************************************************************** ; This file is a basic code template for object module code * ; generation on the PICmicro PIC12F675. This file contains the * ; basic code building blocks to build upon. As a project minimum * ; the 12F675.lkr file will also be required for this file to * ; correctly build. The .lkr files are located in the MPLAB * ; directory. * ; * ; If interrupts are not used all code presented between the * ; code section "INT_VECTOR and code section "MAIN" can be removed. * ; In addition the variable assignments for 'w_temp' and * ; 'status_temp' can be removed. * ; * ; Refer to the MPASM User's Guide for additional information on * ; features of the assembler and linker (Document DS33014). * ; * ; Refer to the respective PICmicro data sheet for additional * ; information on the instruction set. * ; * ;********************************************************************** ; * ; Filename: main.asm * ; Date: 2005-10-25 * ; File Version: 1.0 * ; * ; Author: Rolf Lear * ; Company: Hobby * ; * ; * ;********************************************************************** ; * ; Files required: * ; 12F675.lkr * ; * ; * ;********************************************************************** ; * ; Notes: * ; * ; 2250us on (40khz modulated) ; 27600us off (no signal) ; 650us on ; 1375us off ; 575us on ; 3350us off ; 650us on ; -- repeated a second time after 63ms ; 40KHz implies a 25us cycle time, ; or 12.5us on, then 12.5us off. ; each instruction cycle is 1us@4MHz, thus, we approximate. ; and use 13us on, 12us off. ; * ; COPYRIGHT: Rolf Lear. 2005 * ; Please e-mail me at .....learrKILLspam.....rogers.com before using this code. * ; Free for non-commercial use. * ; * ; ... always wanted to do something like that... * ;********************************************************************** list p=12f675 ; list directive to define processor #include <p12f675.inc> ; processor specific variable definitions errorlevel -302 ; suppress message 302 from list file __CONFIG _CP_OFF & _CPD_OFF & _BODEN_OFF & _MCLRE_OFF & _WDT_OFF & _PWRTE_ON & _INTRC_OSC_NOCLKOUT ; '__CONFIG' directive is used to embed configuration word within .asm file. ; The lables following the directive are located in the respective .inc file. ; See data sheet for additional information on configuration word settings. #define BLKBIT 4 #define BLINK GPIO,4 #define IRBIT 5 #define IRLED GPIO,5 #define TRGBIT 2 #define TRIGGER GPIO,2 ;***** VARIABLE DEFINITIONS (examples) ; example of using Shared Uninitialized Data Section INT_VAR UDATA_SHR 0x20 CCY RES 1 ; Cycle count register CCT RES 1 ; Cycle tempw BLC RES 1 ; Blink Counter. ;********************************************************************** RESET_VECTOR CODE 0x000 ; processor reset vector goto start ; go to beginning of program MAIN CODE ; these first 4 instructions are not required if the internal oscillator is not used start ;call 0x3FF ; retrieve factory calibration value ; My chip returns 0x74 banksel OSCCAL ; set file register bank to 1 movlw 0x74 movwf OSCCAL ; update register with factory cal value ; remaining code goes here banksel INTCON bcf INTCON,GIE ; ensure no interrupts. ; Set the various pins... there are only 8 ;-) banksel GPIO clrf GPIO ; movlw 07h banksel CMCON movwf CMCON ; turn off comparator. banksel ADCON0 clrf ADCON0 ; turn off A/D module. banksel ANSEL clrf ANSEL ; make all pins digital. banksel TRISIO ; movlw 0xff movwf TRISIO bcf TRISIO,IRBIT ; set the IRPIN to output. bcf TRISIO,BLKBIT movlw 0ffh ; Enable all weak-pullups. banksel WPU ; actually, the TRISIO above will movlw WPU ; not allow pull-up on output pins banksel IOC clrf IOC ; disable all IO interrupts. ; OK, init complete... ; lets actually do something. banksel GPIO ; get back to GPIO bank, ; the only file we modify now. ; OK, init complete... ; lets actually do something. ;goto Remote movlw 20 ; reset the counter to 20 blink cycles. movwf BLC ; bsf BLINK ; turn on LED BlinkLoop btfss TRIGGER ; test switch... call Remote call Delay btfss TRIGGER ; test switch... call Remote bcf BLINK ; turn off LED decfsz BLC goto BLOff bsf BLINK ; turn on LED movlw 20 ; reset the counter to 20 blink cycles. movwf BLC ; BLOff call Delay goto BlinkLoop Delay ; exact 50ms movlw 66 movwf CCY movlw 192 movwf CCT goto $+1 ; 2 x nop DelayLoop decfsz CCY,1 goto $+2 return decfsz CCT,1 goto $-1 goto DelayLoop ; 2250us on (40khz modulated) ; 27600us off (no signal) ; 650us on ; 1375us off ; 575us on ; 3350us off ; 650us on ; wash, rinse, repeat. after 63us Remote bcf BLINK call Sequence ; wait 63,000us. or 2520 cycles. = 9x256 + 216 cycles. movlw 216 movwf CCY call CycleOff movlw 0 movwf CCY call CycleOff movlw 0 movwf CCY call CycleOff movlw 0 movwf CCY call CycleOff movlw 0 movwf CCY call CycleOff movlw 0 movwf CCY call CycleOff movlw 0 movwf CCY call CycleOff movlw 0 movwf CCY call CycleOff movlw 0 movwf CCY call CycleOff movlw 0 movwf CCY call CycleOff call Sequence bsf BLINK call Delay call Delay call Delay call Delay bcf BLINK call Delay call Delay bsf BLINK call Delay call Delay call Delay call Delay bcf BLINK call Delay call Delay return Sequence movlw 90 ; 90 x 25us = 2250us ON. movwf CCY call CycleOn movlw 80 ; gives 1104 cycles in total = 27600us movwf CCY ; call CycleOff ; 80 movlw 0 movwf CCY call CycleOff ; 256 movlw 0 movwf CCY call CycleOff ; 256 movlw 0 movwf CCY call CycleOff ; 256 movlw 0 movwf CCY call CycleOff ; 256 ; ------ ; 1104 movlw 26 ; 26 x 25us = 650us ON. movwf CCY call CycleOn movlw 55 ; 55 x 25us = 1375us Off. movwf CCY call CycleOff movlw 23 ; 23 x 25us = 575us ON. movwf CCY call CycleOn movlw 134 ; 134 x 25us = 3350us Off. movwf CCY call CycleOff movlw 26 ; 26 x 25us = 650us ON. movwf CCY call CycleOn return CycleOn ; This will always take the exactly 25 x CCY mcu cycles to complete ; LED will be on at a 13/25 duty cycle ... 52% ;nop ; 22 Every call has a 2-instruction setup movlw ;nop ; 23 second instruction is movwf ;nop ; 24 Every call has 2 instruction call. ;nop ; 25 part 2 of call... bsf IRLED ; 1 open FET... goto $+1 ; 2/3 goto $+1 ; 4/5 goto $+1 ; 6/7 goto $+1 ; 8/9 goto $+1 ; 10/11 goto $+1 ; 12/13 bcf IRLED ; 14 Set pin low. - close FET. nop ; 15 goto $+1 ; 16/17 decfsz CCY,1 ; 18/19 decrement CCY. ; 2 instructions.... goto LoopOn ; 19/20 another 2 cycles return ; 20/21 LoopOn goto $+1 ; 21/22 nop ; 23 goto CycleOn ; 24/25 CycleOff ; This will always take the exactly 25 x CCY mcu cycles to complete ; LED will be off all the time. ;nop ; 1 Every call has a 2-instruction setup movlw ;nop ; 2 second instruction is movwf ;nop ; 3 Every call has 2 instruction call. ;nop ; 4 part 2 of call... nop ; clrf PORTB ; 5 turn OFF LED (make close drain...). nop ; 6 nop ; 7 nop ; 8 nop ; 9 nop ; 10 nop ; 11 nop ; 12 nop ; 13 nop ; 14 nop ; 15 nop ; 16 nop ; 17 nop ; clrf PORTB ; 18 turn OFF LED (close drain... ) decfsz CCY,1 ; 19/20 decrement CCY. ; 2 instructions.... goto LoopOff ; 20/21 another 2 cycles nop ; 21 nop ; 22 nop ; 23 return ; 24/25 LoopOff nop ; 22 nop ; 23 nop ; 24 nop ; 25 nop ; 1 back to start of next loop nop ; 2 goto CycleOff ; 3/4 ; initialize eeprom locations EE CODE 0x2100 DE 0x00, 0x01, 0x02, 0x03 END ; directive 'end of program' part 3 13412 bytes content-type:image/png; (decode) part 4 35 bytes content-type:text/plain; charset="us-ascii" (decoded 7bit)

On Thu, 27 Oct 2005, Rolf wrote: > Now, I have just one question, somewhat off topic.... > > Anyone know how to "broaden" the reception of an IR Receiver. The D70 seems > to have a very "directional" receiver. More than about 15 degrees either side > of where the lens is pointing, and the receiver does not activate (for > neither my remote, nor the Nikon one...). I am reluctant to open the camera > (will not happen), but I am open to suggestions of putting some lens or > something to accomplish the broadening. Taking a divergent lens from a throwaway camera's viewfinder and temporarily securing it in front of the 'eye' of the IR receiver should help (and reduce range). Peter

On Fri, 28 Oct 2005, Spehro Pefhany wrote: > You could try a bit of frosted or pebbled clear plastic. A Fresnel > lens out of a duff motion detector etc. How about scuffing up a bit of > clear sticky tape with emery paper and sticking it over the receiver? That is not a good idea imho. You want to widen the field of view without losing energy if possible. A divergent lens added outside (tacked on) should help, but it will reduce the range. Peter

Rolf wrote : > One other thing... the Oscillator Callibration for *my* chip is 0x74. > You will have to change that value for your chip. Change what ? Your code : ;call 0x3FF ; retrieve factory calibration value ; My chip returns 0x74 banksel OSCCAL ; set file register bank to 1 movlw 0x74 movwf OSCCAL ; update register with factory cal value should/could be replaced with : ;call 0x3FF ; retrieve factory calibration value banksel OSCCAL ; set file register bank to 1 movwf OSCCAL ; update register with factory cal value Why care what the actual value is ? What if you'd like to use that code in 10 or more processors ? Regards, Jan-Erik.

Jan-Erik Soderholm wrote: {Quote hidden}>Rolf wrote : > > > >>One other thing... the Oscillator Callibration for *my* chip is >> >> >0x74. > > >>You will have to change that value for your chip. >> >> > >Change what ? > >Your code : > > ;call 0x3FF ; retrieve factory calibration value > ; My chip returns 0x74 > banksel OSCCAL ; set file register bank to 1 > movlw 0x74 > movwf OSCCAL ; update register with factory cal value > >should/could be replaced with : > > ;call 0x3FF ; retrieve factory calibration value > banksel OSCCAL ; set file register bank to 1 > movwf OSCCAL ; update register with factory cal value > >Why care what the actual value is ? >What if you'd like to use that code in 10 or >more processors ? > > >Regards, >Jan-Erik. > > > > Uhmmm... because I was worried that at 3am some morning while my brain was fried I would erase the chip instead of program it... Actually, I use the DIY Kit 128 with the "MicroPro" software. This is one of my first projects, and certainly the first one with a callibrated Oscilator. I did not know what would happen when I pressed the "Program" button, so I first read the chip, wrote the callibration number (with a sharpie) on to the chip, and in to my code... I realise now that the MicroPro throws up a warning when you program over the callibration value. There is not much documentation (that I can find) about safe-guarding the callibration value in the program memory. Can you point me to something that indicates how to properly deal with the instruction (RETLW 0x??) at 0x3FF? The 12F675 datasheet just indicates that it is there. Actually, I only realised it existed because of the code template in MPLAB, I did all my testing on a 16F628, and then ported it to the 12F675. My reading of the 12F datasheet suddenly became more critical when I realised that the Oscilator was very different in the 12F675. Do all programmers use a similar approach to warning the user when programming the chip that the callibration data is different? Rolf

At 10:30 AM 10/28/2005 -0400, you wrote: >Thanks all... those suggestions seem easy to try... (gets out 3m "frosted" >tape....) > >Holy ...! much better reception angle. The floor I work on is not big >enough to test whether the range is reduced (presumably it is...) > >I got my inspiration from http://www.alanmacek.com/nikon/ who also >references http://www.bigmike.it/ir-control.html >You will want to look at those pages. <snip> Thanks for the info, Rolf-- I'll make one up (probably using a resonator for the clock). Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" EraseMEspeffspam_OUTTakeThisOuTinterlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com ->> Inexpensive test equipment & parts http://search.ebay.com/_W0QQsassZspeff

Rolf wrote: > Uhmmm... because I was worried that at 3am some morning while my brain > was fried I would erase the chip instead of program it... Good programming software makes it difficult to just erase the chip without first reading the calibration value then writing it back afterwards. You can't just erase a chip without saving the calibration value using my PIC_PROG program, for example. It does perform a bulk erase, but always reads the calibration value first, writes it to standard output for reference, does the erase, then write the calibration value back. > so I first read the chip, wrote the > callibration number (with a sharpie) on to the chip, and in to my > code... On the chip is a good idea, since things can still go wrong. If power went down or communication interrupted during the right few 100mS, my programmers could lose the calibration value also. In the code is not a good idea because that code will only work right on one specific chip. You'll probably forget all about that when you pick another chip out of the drawer. > There is not much documentation (that I can find) about safe-guarding > the callibration value in the program memory. Can you point me to > something that indicates how to properly deal with the instruction > (RETLW 0x??) at 0x3FF? In the linker file specify the program memory range from 0 to 3FFEh instead of 0-3FFFh. If you want to you can create a separate region at 3FFFh and declare it protected. > Do all programmers use a similar approach to warning the user when > programming the chip that the callibration data is different? Actually I think it's not possible to overwrite the calibration value with my programming software using the default configuration file. ****************************************************************** Embed Inc, Littleton Massachusetts, (978) 742-9014. #1 PIC consultant in 2004 program year. http://www.embedinc.com/products

Rolf wrote : > Can you point me to something that indicates how to properly > deal with the instruction (RETLW 0x??) at 0x3FF? The 12F675 > datasheet just indicates that it is there. What about "Example 9-1" on page 54 ? (Page number could be different, I'm not sure I have the latest datasheet...) > My reading of the 12F datasheet suddenly became more critical > when I realised that the Oscilator was very different in the 12F675. This is one of the nice things with the 8-pin 12F683. It has the new 8 Mhz INTOSC that is factory callibrated, so there is no calibration value that can be erased at all. Instead there is a OSCTUNE register where you can tune the freq aprox +/- 12% in 32 steps. But the b'00000' (reset value) is always the factory callibrated freq. Besides of that, compared with the 12F675, the 12F683 also have a PWM module, 2 Kword flash and more RAM. Nice chip.... Jan-Erik.