12f675_fuse_about_to_blow!

[mackrackit]

Sounds good to me Is there anything these PIC's can't do......?

Yes... But we do not talk about that here

[LEDave]

Lol......

[mackrackit]

How are you coming with the IRs?

A few years ago I did a laser "trip wire". The same thing can be adapted to IR.

The laser pulses at a given rate so the sensor can not be defeated by another laser or bright light. Think of those silly movies where the laser system is defeated with mirrors and such. Can not happen, or not likely to with this.

I used a simple laser diode like you would find in an office pointer. and a photo-transistor for the sensor. The sensor was placed in a 24 inch long tube so ambient light would not was it out. Night time monitoring would obviously not need this.

So here is the code if you want/need ideas. As always there are several ways to do this that may or may not be more efficient. But this system has been monitoring a quarter mile long line for around three years now.

Laser Pulse:

DEFINE OSC 4

LOOP:
HIGH GPIO.4
PAUSE 20
LOW GPIO.4
PAUSE 95
GOTO LOOP

Laser Sensor:

DEFINE OSC 4
LP	VAR BYTE

START:
COUNT PORTC.1,100,LP
IF LP <> 1 THEN CHECK
HIGH PORTC.5    'HEART BEAT LED
PAUSE 50
LOW PORTC.5    'HEART BEAT LED
PAUSE 50
GOTO START

CHECK:
COUNT PORTC.1,100,LP
IF LP <> 1 THEN BREACH
GOTO START

BREACH:
'DO SOMETHING
GOTO START

[LEDave]

How are you coming with the IRs?

I've been wondering about this:

http://www.maplin.co.uk/Module.aspx?ModuleNo=265568

I know it's not an IR_LED_Lens combo but it does "Provides 5m visibility coverage with a camera"

Interesting project that with the laser. How difficult was it aligning the transmitter with the receiver over that distance?

Dave

[mackrackit]

That LED array looks like it would really light things up. Might just be what you are looking for. The lens idea was for some distance and intensity if you are only using one or two LEDs.

Laser alignment was a ... very difficult.

The laser and sensor are mounted on 2 inch heavy walled pipe cemented into a 3 x 3 x3 foot chunk of concrete. We did/do the alignment at night with a 4 x4 foot piece of plywood to start with. Every once and a while with the change of seasons and all the earth quakes we have here it has to be re-adjusted. At that distance the laser spot is couple of inches in diameter so there is a little forgiveness.. But I should build a bigger target.

[LEDave]

I guess over that distance the trans / rec would have to be mounted rock solid (literally).

You must have a seriously big back garden mackrackit to have to transmit over a quarter mile
I wouldn't like to have to cut you're garden grass

I'm going for the Maplin IR_Display. Do you think it will put enough light out to take a picture at a reasonable shutter speed without using the flash?

Dave

[mackrackit]

I wouldn't like to have to cut you're garden grass

It is all sand where I live with no ocean.

I'm going for the Maplin IR_Display. Do you think it will put enough light out to take a picture at a reasonable shutter speed without using the flash?

I would guess yes if you can place it close enough to the target like you had the PIR in the cereal box. It will be directional like a flash light (hand torch?).