specialized interval timer

[TaZMaNiaK]

Hi there. I am building a prototype device, and it requires a timing circuit that has to work in a very specific way (I've searched high and low for a ready-made solution, to no avail). I can build a circuit from schematic no problem, but I have no idea about theory when it comes to anything more complicated than resistors and diodes. I was wondering if one of you guys would be willing to help me out..

Here's the requirements..

Must operate on 2-3vdc (2 AA or C batteries)
Must be very low drain, looking to be able to run for months without changing batteries
Must be able to drive a small, low current 2-3vdc motor (off same batteries) without a relay
Depending on a switch setting, must run motor for 1 or 2 seconds per actuation
Depending on a switch setting, must provide one actuation every 6,8, or 12 hours (not time critical, just two, three, or four times per day)
Must have a manual actuation switch that does not reset or interrupt timer (ie: if manual button is pressed 5 hours into a 6 hour cycle, it will still actuate automatically 1 hour later).

Pretty simple, right? Here's the kicker: Must have an ambient light rejecting infrared proximity sensor that PAUSES (not resets) the cycle when an object is detected. It must keep the timer paused for a minimum of 5 minutes after the object is no longer detected. After the 5 minute delay, the cycle must continue where it left off. Ambient light rejection is critical, as the detector will be exposed to varying levels of ambient light in normal operation.

The proximity sensor also needs to be as small as possible (no larger than a dime), and must be able to be remotely mounted - say, no more than 3 cable feet off the main board.


So.. Any generous person want to tackle this?

Much thanks in advance!

Matt

 

[ronsimpson]

So.. Any generous person want to tackle this? Matt

Please; what is the meaning of the word GENEROUS?

If the motors will not pull down the batteries then a small micro processor like the PIC10Fxx pr PIC12Fxx will last for years and will do the timing you asked for. I need to think about the proximity sensor. What object? How big?

 

[TaZMaNiaK]

I was thinking about PICs, because I saw them in my Allied catalog and like the price on them.. I have just never used them before so I wasn't sure if they could do that. But if they're easy to program and it'll simplify things, I'm game! As far as the motor pulling the voltage down, I wouldn't be opposed to having a button cell to run the timer and the AA's running the motor.

For the proximity sensor, it would only need to be sensitive to an object passing within about 1/2 to 1 inch. I don't want to post too many details publicly at this time (I'm not sure yet that it's a marketable product, I need to see if it works in real life how it works in my head.. ) but it's a pet product and it would be to detect the pet's presence so as not to activate and injure or startle them.

I was thinking something such as this because it's nice and cheap, small, and doesn't require alignment. It seems to be of similar type to whats in my cell phone, that turns the display off when it's up to my ear..

OPTEK Technology OPB733TR

**broken link removed**