Thanks Paul, you're right, most likely the problem is with the antenna. But the point is that as you know for Micaz, the antenna is a 2.4 ghz pcb antenna! how can I re-solder it? by now I've cut the antenna of one of the motes totally and re-soldered it, but it didn't work and also I resolder another mote (without cutting the antenna first, just by adding more solder to it board), but it didn't work either! any suggestions how can I do it?
And also do you think if the problem is with the connection between MMCX female part and board or the female part itself is damaged? (the antenna should be fine, I tested it by changing a new mote's antenna with a damaged one, and it still was working fine)! thanks again for your help, Mohammad 2009/12/22 Paul Johnson <[email protected]> > Mohammad, > > One thing you may want to check out is the antenna connection to the micaz > board. The board-mounted connector can be pretty fragile and can be easily > broken off if the antenna catches on anything, or you attempt to remove the > antenna by pulling at an angle. What I would do is try to re-solder the > antenna one one of the boards that are malfunctioning and see what happens. > > 10cm is about the range I've seen micaz/mica2 nodes work w/out an antenna > connected at all, so the antenna is likely the cause of this problem. > > Hopefully re-soldering the connections fixes this and you don't have to buy > new boards, > -Paul > > > On 12/22/2009 4:53 PM, Mohammad S. Hashemian wrote: > > 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 > > > _______________________________________________ > Tinyos-help mailing list > [email protected]https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help >
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