maybe you're a candidate for the adept style switch then. ($5 USD max) An overview.. a microswitch is mounted with the lever arm near the pivot of a weighted = cylinder (I use copper tube with a solder plug at the free end) The upwards movement of the strucutre causes the cylinder to rotate on the = pivot, and the natural advatage of the lever arm switches the micro. By adjusting the weight in the free end of the cylinder, I can set my = switches for 2G activation. BTW, ALWAYS use a setpont of 2G or more since you'll easily exceed 1.5 if = the model is jostled on the pad... 2G or 5G are commonly used to prevent = the jostling issues, but 5G is a bit high for heavy models, draggy models, = or slow burn motors. If you need the other method ($0.50 USD) contact me off list after the = weekend and I'll dig out some sketches for you. Des >>> steve_piclist@YAHOO.COM 9/07/03 11:28:04 am >>> Des, My original design uses a "break switch" type system. A few people asked me about designing one that uses a "G SWITCH", like a high number of the ones available from Public Missles, BlackSky, ... etc. The timer that I = sell costs less then US$30.00, a G-SWITCH doesn't seem worth it to me. Thanks. Steve www.xavien.com=20 Des Bromilow wrote: Steve, I make my own. very easy, and quite reliable, very repeatable, etc. Do a search on the adept website for their timers, and check out the = mechanical system they use (a swinging arm, and a microswitch.) I also use another system (even smaller and cheaper) which is a little = harder to make. It's based on a spring from a pen, a small sleeve of = plastic, and a tinned wire. I can explain it if you need, but for = beginnigs I'd suggest the Adept system. Second question.. do you really NEED a G-Switch? The simplest sytems use = break wires, pull pins, etc. These systems sometimes are the ONLY system = that works (particulalry for long burn, slow engines) If you need commercially made G-Switches, get yourself to a supplier like = Jim Ball, or some of the other amatuer suppliers.. be warned, a MIL-SPEC = switch will set you back around $30+ USD. HTH, Des Bromilow Queensland Rocketry Assoc. >>> steve_piclist@YAHOO.COM 9/07/03 5:22:49 am >>> Friends, I am trying to find a company that sells "G-SWITCHES" that are used in = model rocket timers. Do companies make these, I keep seeing references to = them on rocketry related sites, but doing a search with GOOGLE turns up no = suppliers of these things. I can't even find an explanation as to what = they do exactly. Any help much appreciated. Thanks. Steve --------------------------------- Do you Yahoo!? The New Yahoo! Search - Faster. Easier. Bingo. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. ________________________________________________________________________ This email has been scanned for viruses by the CITEC Email Anti-Virus = service powered by MessageLabs. For more information on a proactive email = anti-virus service working around the clock, around the globe, visit = www.citec.com.au=20 ________________________________________________________________________ ________________________________________________________________________ This email has been scanned for viruses by the CITEC Email Anti-Virus = service powered by MessageLabs. For more information on a proactive email = anti-virus service working around the clock, around the globe, visit = www.citec.com.au=20 ________________________________________________________________________ -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. --------------------------------- Do you Yahoo!? The New Yahoo! Search - Faster. Easier. Bingo. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. ________________________________________________________________________ This email has been scanned for viruses by the CITEC Email Anti-Virus = service powered by MessageLabs. For more information on a proactive email = anti-virus service working around the clock, around the globe, visit = www.citec.com.au=20 ________________________________________________________________________ ________________________________________________________________________ This=20email=20has=20been=20scanned=20for=20viruses=20by=20the=20CITEC=20E= mail=20Anti-Virus=20service=20powered=20by=20MessageLabs.=20For=20more=20i= nformation=20on=20a=20proactive=20email=20anti-virus=20service=20working=20= around=20the=20clock,=20around=20the=20globe,=20visit=20www.citec.com.au ________________________________________________________________________ -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.