Just to clarify, what I need to do is close a contact (at various times) under program control, not just when the PC powers up. David... Charles Craft wrote: > Crude but hard to get simpler than a USB controlled plug strip: > http://www.instructables.com/id/A_USB_Power_Controled_Plug_Strip_With_Isolation/ > > > -----Original Message----- > >> From: "David Duffy (AVD)" >> Sent: Jun 12, 2009 2:47 AM >> To: "Microcontroller discussion list - Public." >> Subject: [EE] USB to contact closure >> >> I have an application where a PC needs to trigger another device via a >> contact closure. The current PCs have serial, parallel and USB ports >> available, but in future one may only have USB. >> >> My first thought was an FT232 USB-serial chip and a small micro driving >> a reed relay, but I'm trying to simplify the design and get the cost >> down as there's potentially 1000 or so units to deploy. >> >> I've never delved into "USB on a PIC" so don't know how easy it is. Also >> bear in mind I have no C language experience. >> >> My other thought was to keep the FT232 and ditch the PIC, simply using >> one of the serial control lines to trigger the relay. >> >> The consequence of erroneously activating the relay during PC powering >> up is not too much of a problem. (I have to confirm this) >> >> Does anyone else have any ideas? >> David... >> -- ___________________________________________ David Duffy Audio Visual Devices P/L Unit 8, 10 Hook St, Capalaba 4157 Australia Ph: +61 7 38235717 Fax: +61 7 38234717 Our Web Site: www.audiovisualdevices.com.au ___________________________________________ -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist