Hi All We have run a project using micaz modules. In this project there are 8 nodes which are fixed in a certain locations and 40 nodes which are carried by different people (some of these motes are in XBow boxes and some other are just in small pouches). There are 3 motes which are used as base stations through the environment.
The problem we have now is that the transmitter of the mobile motes gets damaged after a while. For example we pick a new mote out of the pack, program it, and give it to one of the people, after a while (sometimes even after 3 days!!!) the transmitter (either sender or receiver) stops working. I realize the transmitter of a mote has stopped working when I don't receive any signal from it for a couple of days. In this case I test the mote with CountSend and CountReceive (shipped with XBow MoteWorks) against another new mote. Usually the result is that either the sender part or receiver part of the mote has become so weak that the packet can be transferred only if the motes are less than 10 cm away!!! further than that the packet either can not be sent or be received. I've called the company regarding this issue and they told me if the mote doesn't work with CountSend and CountReceive, you should send them back here for diagnosis and because by now they are out of warranty, it costs 100$ per each for diagnosis (The motes have been bought more than a year ago, but they haven't been used at all). On possibility was that the motes that we got have been produced using a bad batch in the manufacture for transmitter, and that's why they keep dying in work. But it's not very likely because the problem is just exist with the mobile ones, not with the base stations or with the fixed motes. Also the currently used motes have been purchased in two separate orders, and probably two separate manufacturing series. The other possibility is that they die because of the static electricity (people are supposed to change the mote's battery every couple of days). Can it be a reason? But this even happens for the mobile motes with XBow boxes which they look safe for this. and if it's the reason, why just the transmitter gets damaged and no other part in the mote? By now we have lost more than 30 micaz motes this way and if it wants to continue we will much more. Does anyone has any idea what can be the reason and how we can stop it? Any idea is highly appreciated. Thanks, -- Mohammad S. Hashemian Research Scholar/DISCUS Lab Department of Computer Science 254.2 Thorvaldson Building University of Saskatchewan (306)966-1947
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