08 February 2008

Wireless rechargeable high-intensity reading light for $23.75

Ingredients: 1xLED Torch ($4 from Reject store), 3xAAA eneloop NiMH rechargeable ($6.50 a cell from Tricky Dickey), wire coat-hanger (free after shop use), super-glue ($1 for a pack of 4 tubes from Reject), large/thin peg (free from random source, guess about 12¢ ea in large-ish packs new). Will publish photos in a few days (’net access permitting).

Method: swap boring (Super Heavy Duty) AAAs with torch for rechargeable. Wind coat-hanger around torch to not obscure the unscrewable end, optionally super-glue into place. Match short straight length of coat-hanger against side of peg, super-glue it into place (range of about 45cm for large-ish books, 30cm for simple paperbacks.

Useage: click switch on unscrewable end of torch, clip peg onto book cover, read.

These little $4 torches have 9 very intense LEDs therein, so light up the book quite well; the “eneloop” badged (Sanyo) 800mAh AAA cells drive them quite brightly (will drive high-current loads like cameras quite well), & retain 85% of a full charge over an entire idle year, even in coldness.

Advantage in doing this manually is cost ($23.75 vs $33.95 plus batteries ($53.45 all up)) & immediate availability of readily rechargeable power cells & yer dunnit yerself (craftsmanship, even if (especially if) it takes a few tries to build the ideal beastie).

For bonus craftsmanship points, spung the LED assembly from the torch & tweak the LEDs to spread more, so cover entire page at a shorter range.

Buy 3 more cells & you can recharge spent cell sets faster than you can spend charged ones.

One-off construction cost: obtain a charger & 4xAA (not AAA, sadly) NiMH cells from BigW for $18.85 a set. Run camera, bike lamp, other devices on the AAs.

Optional extra mechanism: obtain clip-board, glue coat-hanger to clip-board (maybe in 2x locations) instead of peg, place book on clip-board to read.

3 comments:

Leon Brooks said...

Just dabbled in a Noam Chomsky book, which quotes Wilhelm von Humboldt saying:

“man never regards what he possesses as so much his own, as what he does; & the labourer who tends a garden is perhaps in a truer sense its owner then the listless voluptuary who enjoys its fruits.”

I think that emphasises (in a non-tech flavour) a core principle of FOSS.

Leon Brooks said...

Also discovered a Reject store in the Booragoon shopping centre, so now sand-gropers (as well as crow-eaters & probably others) can easily acquire this electrical wonderment. (-:

KMart also has rechargeable AAAs for about a dollar (each) less.

GregoryO said...

I got some NiMH AAs and AAAs for <$2 ea a few months ago - a friend of mine is a supplier of sorts. Minimum quantity of four. Not the largest mA rating, but a pretty good deal in my books.