Low power LED PVC flashlight

Matthew writes – “Scouring the Internet for information on LEDs, I accidentally stumbled upon a PDF detailing a flashlight made from PVC. For the torch, he biases ultra-bright LEDs with ballast resistors as described in my LED lighting guide. This is a simple solution, but a with a slightly more complicated circuit we can extend battery life by over ten times!” – [via] PDF link.

Related:

• See all sorts of weird things made from PVC – Link.
• Backyard Zip Line by Dave Mabe. Be the hit of the neighborhood with a high-flying, tree-to-tree transporter. MAKE 05 – Page 72.
• The Night Lighter by William Gurstelle. Launch potato projectiles 200+ yards with this stun-gun triggered, high-powered potato cannon with see-thru action. MAKE 03 – Page 108.
• HowToons– Make a marshmallow shooter. MAKE 02 – Page 172.