---- START NEW MESSAGE --- Received: from cherry.ease.lsoft.com [209.119.0.109] by dpmail10.doteasy.com with ESMTP (SMTPD32-8.05) id A2029630208; Wed, 28 Jan 2004 16:21:22 -0800 Received: from PEAR.EASE.LSOFT.COM (209.119.0.19) by cherry.ease.lsoft.com (LSMTP for Digital Unix v1.1b) with SMTP id <21.00CC1B3A@cherry.ease.lsoft.com>; Wed, 28 Jan 2004 19:21:07 -0500 Received: from MITVMA.MIT.EDU by MITVMA.MIT.EDU (LISTSERV-TCP/IP release 1.8e) with spool id 0664 for PICLIST@MITVMA.MIT.EDU; Wed, 28 Jan 2004 19:21:01 -0500 Received: from MITVMA (NJE origin SMTP@MITVMA) by MITVMA.MIT.EDU (LMail V1.2d/1.8d) with BSMTP id 9714; Wed, 28 Jan 2004 19:20:15 -0500 Received: from albatross-ext.wise.edt.ericsson.se [193.180.251.49] by mitvma.mit.edu (IBM VM SMTP Level 430) via TCP with ESMTP ; Wed, 28 Jan 2004 19:20:14 EST X-Comment: mitvma.mit.edu: Mail was sent by albatross-ext.wise.edt.ericsson.se Received: from esealnt612.al.sw.ericsson.se ([153.88.254.118]) by albatross-ext.wise.edt.ericsson.se (8.12.10/8.12.10/WIREfire-1.8b) with ESMTP id i0T0KGqY029066 for ; Thu, 29 Jan 2004 01:20:16 +0100 (MET) Received: by esealnt612.al.sw.ericsson.se with Internet Mail Service (5.5.2657.72) id ; Thu, 29 Jan 2004 01:20:16 +0100 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2657.72) Content-Type: text/plain Message-ID: <37FB7AA6F5F9814FB634A7BF4C35A6F5640CF0@ESEALNT442.al.sw.ericsson.se> Date: Thu, 29 Jan 2004 01:20:02 +0100 Reply-To: pic microcontroller discussion list Sender: pic microcontroller discussion list From: "Jan-Erik Soderholm XA (TN/PAC)" Subject: Re: [PIC:] Disassemblers To: PICLIST@MITVMA.MIT.EDU Precedence: list X-RCPT-TO: Status: U X-UIDL: 371856176 Liam O'Hagan wrote : > Sorry to be so roundabout in my description, by necessity > there are a lot of security concerns with an issue like this. Hm, even *mentioning* it seems to be on the "security edge"... :-) Jan-Erik. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics . Return-Path: <> Received: from mitvma.mit.edu ([18.92.0.3]) by tomts17-srv.bellnexxia.net (InterMail vM.5.01.06.05 201-253-122-130-105-20030824) with ESMTP id <20040130073729.HOBC17233.tomts17-srv.bellnexxia.net@mitvma.mit.edu> for ; Fri, 30 Jan 2004 02:37:29 -0500 Received: by mitvma.mit.edu (IBM VM SMTP Level 430) via spool with SMTP id 8247 ; Fri, 30 Jan 2004 02:37:25 EST Received: from MITVMA.MIT.EDU (NJE origin LISTSERV@MITVMA) by MITVMA.MIT.EDU (LMail V1.2d/1.8d) with BSMTP id 9193; Fri, 30 Jan 2004 02:37:26 -0500 Date: Fri, 30 Jan 2004 02:37:26 -0500 From: "L-Soft list server at MITVMA.MIT.EDU (1.8e)" Subject: PICLIST: error report from YAHOO.CO.UK To: listsjosh@3MTMP.COM, "For Blackholeeclipse@Earthlink.Net" Message-ID: X-LSV-ListID: None The enclosed message has been identified as a delivery error for the PICLIST list because it was sent to 'owner-piclist@MITVMA.MIT.EDU'. ------------------------------ Message in error ------------------------------- Received: from MITVMA (NJE origin SMTP@MITVMA) by MITVMA.MIT.EDU (LMail V1.2d/1.8d) with BSMTP id 9191; Fri, 30 Jan 2004 02:37:26 -0500 Received: from mta108.mail.ukl.yahoo.com [217.12.11.45] by mitvma.mit.edu (IBM VM SMTP Level 430) via TCP with SMTP ; Fri, 30 Jan 2004 02:37:25 EST X-Comment: mitvma.mit.edu: Mail was sent by mta108.mail.ukl.yahoo.com From: MAILER-DAEMON@yahoo.co.uk To: owner-piclist@mitvma.mit.edu X-Loop: MAILER-DAEMON@yahoo.co.uk Subject: Delivery failure Message from yahoo.co.uk. Unable to deliver message to the following address(es). : Sorry, your message to viniciusbh@yahoo.co.uk cannot be delivered. This account is over quota. --- Original message follows. Return-Path: Received: from 209.119.0.109 (EHLO cherry.ease.lsoft.com) (209.119.0.109) by mta108.mail.ukl.yahoo.com with SMTP; Fri, 30 Jan 2004 07:37:27 +0000 Received: from PEAR.EASE.LSOFT.COM (209.119.0.19) by cherry.ease.lsoft.com (LSMTP for Digital Unix v1.1b) with SMTP id <4.00CC4410@cherry.ease.lsoft.com>; Fri, 30 Jan 2004 1:54:27 -0500 Received: from MITVMA.MIT.EDU by MITVMA.MIT.EDU (LISTSERV-TCP/IP release 1.8e) with spool id 1740 for PICLIST@MITVMA.MIT.EDU; Fri, 30 Jan 2004 01:54:18 -0500 Received: from MITVMA (NJE origin SMTP@MITVMA) by MITVMA.MIT.EDU (LMail V1.2d/1.8d) with BSMTP id 8278; Fri, 30 Jan 2004 01:54:03 -0500 Received: from linda-1.paradise.net.nz [202.0.58.20] by mitvma.mit.edu (IBM VM SMTP Level 430) via TCP with ESMTP ; Fri, 30 Jan 2004 01:54:02 EST X-Comment: mitvma.mit.edu: Mail was sent by linda-1.paradise.net.nz Received: from smtp-2.paradise.net.nz (smtp-2a.paradise.net.nz [202.0.32.195]) by linda-1.paradise.net.nz (Paradise.net.nz) with ESMTP id <0HSA000DGJ63QQ@linda-1.paradise.net.nz> for PICLIST@MITVMA.MIT.EDU; Fri, 30 Jan 2004 19:54:03 +1300 (NZDT) Received: from Paradise (202-0-40-37.adsl.paradise.net.nz [202.0.40.37]) by smtp-2.paradise.net.nz (Postfix) with SMTP id 026239E2FF for ; Fri, 30 Jan 2004 19:54:03 +1300 (NZDT) MIME-version: 1.0 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-Mailer: Microsoft Outlook Express 6.00.2800.1158 Content-type: text/plain; charset=iso-8859-1 Content-transfer-encoding: 7bit X-Priority: 3 X-MSMail-priority: Normal References: <001b01c3e6ec$bd319740$0301a8c0@user88l53zxzyb> Message-ID: <00db01c3e6fd$f4e3f3c0$7b01a8c0@Paradise> Date: Fri, 30 Jan 2004 19:54:48 +1300 Reply-To: pic microcontroller discussion list Sender: pic microcontroller discussion list From: Russell McMahon Subject: Re: [EE]: Challenge for keen minds To: PICLIST@MITVMA.MIT.EDU Precedence: list > I have to implement a gate opening detector. It will log date and time each > time the gate is open and for how long. Must be battery-driven, battery must > last as much as possible, must be rugged and robust, and tamper-proof. > People WILL try to defeat it. Depends how techno savvy the defeaters are. You could consider a "spike" that entered a hole in the lock when the gate was shut. The spike may give the appearance of being a mechanical key equivalent but also have some other attribute. eg a slug of brass at the proper place in the spike would DECREASE inductance of a proximate coil that it penetrated and be very hard to simulate if they were not aware what you were doing. Similarly, ferrite or even just steel at SOME but not all locations along the spike would allow selective inductance increase on some proximate coils only. Proper code would be present only when gate was fully shut. Again, users don't SEE any visible mechanism to do the coding. Replicating the spike shape helps not at all. Even 2 or 3 coils would probably be enough with one being triggered when the other(s) weren't by the proper spike. You could have a magnet at the spike end and a sensor (even reed switch) that triggered it when the gate started to open. That way power could be essentially off until the sensor was triggered. Battery consumption should be easy to keep low if you use sensors (as above) that notify you only when mechanical action is taking place. This could be part of the gate latching mechanism or could be independent. The trouble with IR as a comms method is that you either need to have the rcvr always on or have to wake it to listen to you. If you are able to open and shut the gate before doing comms then you could wake the IR up for a brief period at each event. Something like capacitance coupled comms (I know of one device that uses this) or inductive coupling require closish proximity but can be power free until you need to use them. Is it OK to be in close proximity or do you have to be at a distance away? If using IR "semi covertly" you could arrange to power up the receiver every say 10 seconds and listen for an interrogation signal. You can get real time clock IC's with wakeup function that draw sub 1 uA. Your processor need draw power only when it is active and using the "wake on demand" system as above battery drain can be very low. Imagine a device that requires 10 mA for 1 second any time the gate is opened or shut. A 100 mAH battery (modest) would support 100/10 x 3600/2 = 1800 odd opening and shutting pairs. That's about 2.5 per hour 24/7 for a year. A set of AA alkaline batteries would give about 20 times as much as this! Russell McMahon -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body *** MESSAGE TRUNCATED *** .. .