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Question on a timer for lights and fan

I have a few questions on ic timers. I'm looking for a timer to trigger a relay to run an 80mm fan for 1 minute every 2 hours or somewhere around there. I would also like to have the circuit trigger a led light setup for 4 or 5 hours every day.

First off I'm wondering if this is possible with a 556 timer, and if so I have no clue on the parts I need. I've done a bunch of searching and can't find the info I'm looking. If anyone knows of some sites I could look at to read up how this can be accomplished it would be very much appreciated.

Also does anyone know how long a circuit like this will run accurately on a single battery charge, it doesn't need to be exact to the second, just switch the relays on and off reasonably close to on time.

If i remember correctly from my intro to engineering class we programed a simple robot to run an obstacle and as the batteries were used up the timing was slowed.

If you haven't guessed already I'm new to circuits, but I'm pretty sure with a little bit of guidance I can figure this out.

Thank You in advance for any advice on my project.

Westby

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arwestby
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Timers like the 555 and 556 are better for delays measured in seconds or shorter. When you need delays measured in minutes or hours, it is usually best to combine a timer, other oscillator or power line based clock frequency with a multi bit counter. e,g, one of these:

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You pick the counter that has about the right output frequency and adjust the oscillator for the right time, or combine several output bits with logic when using a fixed clock frequency (like the power line).

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Regards,

John Popelish
Reply to
John Popelish

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