You could use a reed relay & turn it on by bringing a magnet close. Or use a version of roman's (http://www.romanblack.com/self_swi.htm) - modified to suit your turn off signal?? Richard P Josh Koffman cc: Sent by: pic Subject: [EE]: Portable Power Switch? microcontrolle r discussion list 27/03/03 13:30 Please respond to pic microcontrolle r discussion list Hi all. I'm planning on embedding a rechargable battery (actually a Sony gumpack style NiMH cell) into a small transmitter. I will build in a charging circuit based on the Maxim MAX712 charger controller. My problem is this: I need to be able to toggle power on and off through a waterproof membrane. It's a bit flexible, but not enough to allow a standard push on-off type switch. I was thinking about using a small tactile momentary switch and an SCR, but I don't think I can get that to work. The problem is getting a normally closed tactile to act as the "off" switch. This is a one off, of course. So here are my specs. I need a power switch/controller type of circuit that can be turned on and off using small normally open tactile switch, or two switches, that would be fine too. Size, power consumption, and ease of construction would also be factors. I would prefer to not have to order some esotheric switch from elsewhere. Any ideas? Thanks, Josh -- A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. -Douglas Adams -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body