Thanks again to all who replied. What I didn't make clear is that I will be doing this in a matter of days and my LED pulsing setup is already designed and built(and works), so I can't make major changes to it electronically. It already has a large electrolytic right across the power supply on the same board as the LEDs(thanks for the suggestion, Fr. Tom). It uses a 16F84 to pulse the LEDs (via a TIP120) at an exact rate of 2907 Hz. The current being drawn by it is fairly constant (about 15% ripple on it). Even so, it causes a volt or so drop from a string of 8 D cells in series (they might not be the absolute freshest D cells). I think I am going to split the difference. I am going to try to fly the supply (possibly a bunch of fresh A cells, and might add a few more than 8 to keep the voltage up), but also have a 10 foot or so copper wire dangling down which will contact the ground first, to discharge the thing before I touch it. I'll use kite string as suggested. I think I'll also use one more balloon than is necessary, in case one gets popped. (a 40" He balloon can lift about 1.2 pounds according to my calculations). If I do end up using wires to the ground, I would either ground both or use a switch which would ground the second one when not connected (I was planning on having a switch to turn it off due to the high current drain). Thanks again, and I will be sure to let you guys know how it goes. The rocket is coming together nicely, and has TWO PICs in it :-) A 16F876 and a 16F84. The sensor works pretty well with the addition of a 38 mm lens. I plan on having video of it, and might digitize it and put it on my web site if it isn't too embarrassing (like a "lawn dart" maneuver right after launch) ! Sean At 11:51 PM 8/12/00 -0400, Donald L Burdette wrote: >So - I'm for using helium balloons, batteries on the ground, grounded >(one side only), thin wires, and kite string. > | | Sean Breheny | Amateur Radio Callsign: KA3YXM | Electrical Engineering Student \--------------=---------------- Save lives, please look at http://www.all.org Personal page: http://www.people.cornell.edu/pages/shb7 mailto:shb7@cornell.edu ICQ #: 3329174 ____________NetZero Free Internet Access and Email_________ Download Now http://www.netzero.net/download/index.html Request a CDROM 1-800-333-3633 ___________________________________________________________ -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu