Replacing existing pic

[mackrackit]

Search the forum for Mel's Olympic Timer and RTC. The might do the trick.

Paul has one also.

[mackrackit]

http://www.picbasic.co.uk/forum/show...eal+time+clock

http://www.picbasic.co.uk/forum/show...=olympic+timer

[Freman]

Thanks mackrackit, I'll have a look at these.

I've already worked out I can't rely simply on adding 1 to a word (while in theory this works, in reality there's quite a deviation)

I am prepared to fall back on pullies, string, and a piece of pvc with a magnet/reed switches if I have to - this will allow me to put the sensors out of sight... hopefully

[skimask]

I am prepared to fall back on pullies, string, and a piece of pvc with a magnet/reed switches if I have to - this will allow me to put the sensors out of sight... hopefully

Haven't read the whole thread..but...
Couldn't you put a small piece of something reflective on the back of the screen, have an IR led/detector module or similar mounted in the wall behind the screen, if even a few feet behind the screen, and use the detector output as the start/stop sensor? One gets set up so when the beam is there (i.e. reflective piece is bouncing back the light), the screen is all the way down, the other is set up at the top so when the beam is there, the screen isn't quite all the way up. You really wouldn't even need the beam on continuously, just a quick blip every second or so might tell you what you want to know.

[Freman]

I did consider that - and it's not off the drawing board.

I was concerned with the amount of bending anything reflective attached to the back of the screen might suffer - I was also worried about possible damage of the front facing screen (it's a glass beaded screen).

I suppose if it came down to it, I could drill a small hole in the support behind the screen (it's held free-standing from the wall/ceiling by two large timber towers - full of dvd's ) and stick something reflective to the backside of the felt side strips.

I've looked at http://www.rentron.com/PicBasic/infr..._detection.htm for the basic idea - I just need to find something that's reflective, sticky, and can handle being rolled and unrolled over and over again.

[skimask]

Bending - well, you really wouldn't need anything crazy. I'd bet just a piece of scotch tape would reflect well enough. Or maybe a piece of black electrical tape...the inverse of what I was thinking earlier...it DOESN'T reflect.

As far as sticky and reflective, why even use any tape at all? The white screen itself should be reflective enough to bounce some light back into a sensor. Then it would be a matter of 'dialing out' the ambient light.

[Freman]

It would be mounted behind the screen - the back side of the screen is a flat black - haven't tested it's reflectivity.

The other alternative is to use one piece of shiny 'something' on the back of the screen at the bottom (where it doesn't bend) and use 2 detectors.

Which of these would you use?
* Phototransistor (Say: http://tinyurl.com/5bspbk for example)
* Photodiode (Say: http://tinyurl.com/58wuwp for example)
* or a full on IR Receiver (Like: http://tinyurl.com/54vqs6) and PWM the IR led(s) to the right frequency.

Edit: Oooh, just found the Sharp IS471F proximity detector... that could be nice - cept for shipping - I can pick the other options up locally...