---- START NEW MESSAGE --- Received: from cherry.ease.lsoft.com [209.119.0.109] by dpmail10.doteasy.com with ESMTP (SMTPD32-8.05) id AD693EA016E; Fri, 30 Jan 2004 11:15:53 -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 <19.00CC5155@cherry.ease.lsoft.com>; Fri, 30 Jan 2004 14:07:58 -0500 Received: from MITVMA.MIT.EDU by MITVMA.MIT.EDU (LISTSERV-TCP/IP release 1.8e) with spool id 3852 for PICLIST@MITVMA.MIT.EDU; Fri, 30 Jan 2004 14:07:50 -0500 Received: from MITVMA (NJE origin SMTP@MITVMA) by MITVMA.MIT.EDU (LMail V1.2d/1.8d) with BSMTP id 7154; Fri, 30 Jan 2004 14:05:46 -0500 Received: from out011.verizon.net [206.46.170.135] by mitvma.mit.edu (IBM VM SMTP Level 430) via TCP with SMTP ; Fri, 30 Jan 2004 14:05:45 EST X-Comment: mitvma.mit.edu: Mail was sent by out011.verizon.net Received: from dell8100 ([4.2.163.193]) by out011.verizon.net (InterMail vM.5.01.06.06 201-253-122-130-106-20030910) with ESMTP id <20040130190548.NKCC17235.out011.verizon.net@dell8100> for ; Fri, 30 Jan 2004 13:05:48 -0600 References: <401A9A93.20071.28A7C0C@localhost> <006201c3e75d$14b7f200$0301a8c0@user88l53zxzyb> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-Authentication-Info: Submitted using SMTP AUTH at out011.verizon.net from [4.2.163.193] at Fri, 30 Jan 2004 13:05:47 -0600 Message-ID: <004101c3e764$0edaec00$5300a8c0@dell8100> Date: Fri, 30 Jan 2004 14:04:56 -0500 Reply-To: pic microcontroller discussion list Sender: pic microcontroller discussion list From: Bob Ammerman Subject: Re: [EE]: Challenge for keen minds To: PICLIST@MITVMA.MIT.EDU Precedence: list X-RCPT-TO: Status: U X-UIDL: 371856552 I assume you are only going to need to check the results if something has been stolen, so a bit of difficulty in retrieving the log isn't too bad. Now, if the bad guys don't know you're trying to monitor the box, something as simple as a light sensor could work (ie: if there is any light, then the door is open). Obviously, if they know about the sensor they could open the box in the dark and then cover the sensor. Alternatively, you could build a robust little box containing an IR LED and IR sensor and mount it (weld it?) to the top of the door frame. When the door is closed the sensor can see the LED. When the door is opened the sensor can no longer see the LED. The same IR LED could be used to transmit the log data. Bob Ammerman RAm Systems ----- Original Message ----- From: "Pedro Drummond" To: Sent: Friday, January 30, 2004 1:12 PM Subject: Re: [EE]: Challenge for keen minds > Thank you all for the help and interest. > > Ok, time for more data: > > The space being protected is a metallic box, the size of an elevator, that > will be towed by small trucks. Its metallic "door" (actually a double door) > is the gate I mentioned. During long trips, these boxes are commonly moved > from truck to truck, with long periods waiting for the next one, with no > guards nearby. Although there is a very strong lock, theft was detected at > final destination in locked boxes (i.e., someone opened it, took some goods, > and somehow relocked it). A redesign of the metal box is being made, but it > will be a long time until all of them are replaced. It is enough for now to > help the insurance company in detecting WHEN and for HOW LONG it was opened, > so the responsible will be known. > I do not mind reading its information only when the gate is open, and I > cannot modify the gate, only add some small device close to the door. > > > To comment some of the group ideas: > > Using a contact method for data transfer - I am afraid of dust, grease, etc. > But maybe. > RFID - cheap tag, but expensive sensor (I guess). > Gyro/acceleration sensors - can't do, since it will be towed by a truck. > Hinge sensored - can't alter the hinge. > > > BTW, special thanks to Russel ! > > -- > 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 .