Like other people mentionned, persistence of vision thingy will save some juice. You could probably use the PWM ports on the PIC to save some power. Or the multiplexing scheme mentionned previously. Personally, I use at least 1K ohm for the LEDs to save power. They always look bright enough for me. Good luck. Peace MJ Brush ----- Original Message ----- From: "Lindy Mayfield" To: Sent: Friday, June 04, 2004 2:47 PM Subject: [PIC:] First Project Finished! But... it used up all my bat tree Hi Guys. I finished my first project! Finally. I got the idea from Mike Predeko's book for the LED clock. But I couldn't find the right parts to put together the multiplexing for all the LED's, so I decided to work with what I have available and made a binary clock: 20 small 3mm LED's that show the hours, minutes, and seconds in bcd binary. The design so far is simply a 9v battery, a 5v voltage regulator, a PIC 16f877, a 32.768 kHz crystal + 2 22pf caps, resistors and LED's, and one resistor tied to MCLR. The programming was fun. Building and soldering the rat's nest out of wires on the back of the board wasn't. (-: (Took 3 weeks.) I left it running for a test last night and it sucked all the juice out of my 9 volt battery in just a few hours. Would someone give me hints as to how to figure out what the problem is why it is using so much power? Thanks in advance. Lindy --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.663 / Virus Database: 426 - Release Date: 4/20/2004 -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu