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Toddler clock engineering

Posted on December 04, 2008 at 13:56:16 by chris

Oscar, our two year old, has an annoying habit of waking up too early, generally about half an hour before our alarm. You can't complain too much - how is he to know if it's 7am (getting up time) or 6am (too early), when it's dark outside either way?

So I thought what we need is some sort of clock that can tell him whether it's time to get up or not. During the half hour of listening to him complaining this morning, we came up with several ideas:

• Build a device (say using a small PIC, which I have handy in the workshop) which which would turn on a little LED at 7am. Simple, but would take some time to develop. More complicated once you want to be able to set the clock and wake up time.
• Modify a clock radio we don't use much - tap into the alarm circuit to switch on a small light. Probably takes less time, though there's a shortage of sockets in Oscar's room.
• A simpler version of the first idea - an even simpler device with some kind of serial (RS-485?) interface which could be controlled by the NSLU-2 under the stairs. Wiring isn't a problem as there are spare RJ45 points both in Oscar's room and under the stairs, which could be connected together at the patch panel. I'd need to build an RS-485 adapter for the NSLU-2 end as well.
• Might be able to use one of the old mobile phones I have lying around. They should still work in offline mode without a SIM. Would need to work out how to get them to turn on the screen backlight at the right time and brightness, though.

As I was designing ever more complicated, flexible, and overengineered solutions, each requiring more time to implement than the last (and time is not something I have in abundance), Yasmin came up with the simplest, most optimal solution:

• A night light and one of those socket timers.

It's simple, effective, quick to implement, and free (if we can find those socket timers...). The perfect solution, and no software or soldering iron work needed. (Darn!)