Interior light with auto off

Here is a solution to the dreaded dead battery due to leaving the seat open with the light on!

First off I replaced the original bulb with a LED version. Unfortunately, I didn’t check the length of the bulb and had to solder the end caps to the bottom of the LED board. This dropped the current by almost half (110mA) and I gained a nice bright white light. But that just meant it would take longer to drain the battery should I leave the seat open.

The solution was obvious when sitting in my car one night, it automatically powered down the interior light after a few minutes, just what we needed. I’m sure with some searching a suitable donor unit from a car could be found but a search on Ebay found some readymade 12v relay timers which could be adapted for the job. Some soldering later I ended up with an interior light unit that switches its self off after 5 minutes

I've uploaded a basic guide (pdf) with some photos of what I did on another site as its too big for me to directly load it here, maybe one of the Admins could grab it and place it here in case it disappears from there in the future.

Interior_light_with_auto_off.pdf

If you need more detail post your question here

You can find an assortment of festoon LED light bulbs here:
http://www.superbrightleds.com/cgi-bin/store/index.cgi?action=DispPage&Page2Disp=%2Ffestoon.html

That should make the first part simpler.
If someone would like to measure the bulb in their swing and
post the proper size, it would benefit everyone.
Or if you found what was the proper size, maybe you could post it.

The other part of your solution is interesting and unique.
What was the cost of your materials and timer including shipping?

This way people with the necessary soldering skills can make an
informed choice on the relative costs involved compared to the
replacement light with the switch on it, which is around $22.00+S&H.

Thanks, for the info.

Dan

The timer l got cost £6.50 inc postage from an eBay user called milendr. Check out Item number: 270906122933 I got the 660 second version.

Right now that's about $10.30 USD.
Certainly cheaper than the replacement switch.

I neglected to consider that availability and postage would be
different in the UK, for the relay timer, the switch and the bulbs.

The same eBay guy posts worldwide

I'm sure any electronics hobbyist could make a similar timer maybe even smaller as we don't need a 10A relay switch our bulb or that huge capacitor.

Heres a circuit that could be suitable: http://www.kpsec.freeuk.com/projects/timer.htm