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:

> 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


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