One other common thing between all the failed motes is that as I said they've been carried by humans, and here in the place that I live, the outside temperature is usually between -20 to -30 or even -40 (unbelievable, I know LOL) and the people are usually outside for at least 15 or 20 minutes per day. Can this causes electric discharge on the mote and therefore the failure of the receiver module of the mote?
Thanks, Mohammad 2010/1/4 Mohammad S. Hashemian <[email protected]> > Thanks Paul, > > Actually I found one more thing. The common point with all of the failed > motes (currently 22 motes) is that the send part of all of them works fine, > but the receiver doesn't operate! I checked the board to see if there is any > obvious problem, but nothing. I think as you said the best way is to contact > the company and ask them to do the diagnostics, hopefully this helps. > > > Thanks again for your help, > Mohammad > > 2010/1/3 Paul Johnson <[email protected]> > > Unfortunately, i'm not sure what else could be the problem. Maybe compare >> a working board with a non-working one and see if any components have fallen >> off or become loose? The people who have be using the broken boards, is >> there anything they have done in common? Dropped board, static discharge, >> improperly secured (put inside of purse/backpack with no protection) etc? >> >> At first glance, it appeared as if the boards were not able to communicate >> because the antenna was not working properly, but from what you've done, it >> doesn't seem to be. >> >> As a last resort, you may want to look into having one mote diagnosed by >> Crossbow. If they can find out the problem, it may be possible that you can >> do the repairs yourself in-house. >> >> Sorry I couldn't be of much help. >> >> -Paul >> >> >> On 1/3/2010 2:30 PM, Mohammad S. Hashemian wrote: >> >> Hello again, >> >> I'm still waiting for any answer from your side Paul (or anyone else). Can >> you think about any other problem in the mote that might cause the problem >> (or anything which goes wrong in the current case)? >> >> Thanks alot for your help, >> Mohammad >> >> 2009/12/30 Mohammad S. Hashemian <[email protected]> >> >>> Hi Paul, >>> >>> I tested this case with some help, but apparently this is not the reason >>> for failure. I took one new mote out of the pack and a broken one. The >>> broken one could xmit the packet at most over 20 cm with antenna, but if you >>> would detach the whole antenna (with MMCX connector) from the board, it >>> would xmit at most over 2 or 3 cm. While with the new one, it could xmit the >>> packets over even 1.5 or two meters after detaching the whole antenna part >>> (antenna + MMCX connector). >>> So I did one more test, I swapped the antenna and MMCX connector of the >>> new mote with the old one and re-soldered it, so the new mote had the >>> antenna + MMCX connector of the broken mote and vice versa. But still the >>> problem was there, the new mote could work fine and the old one couldn't >>> transmit more then 10 or 20 cms!!! >>> Do you have any idea what part of the board may have the problem? >>> >>> Thanks, >>> Mohammad >>> >>> 2009/12/23 Mohammad S. Hashemian <[email protected]> >>> >>> Thanks again, actually I have a software background and I'm not very good >>>> in this soldering thing, especially with this small board and limited tools >>>> we have in our lab. I'll try these ways and I'll tell you what happens. >>>> >>>> Mohammad >>>> >>>> 2009/12/23 Paul Johnson <[email protected]> >>>> >>>> Mohammad, >>>>> >>>>> Yes, I believe the problem is with the actual connector that is MMCX >>>>> adapter soldered to the board, i've had problems with them coming >>>>> completely >>>>> off the board and taking the PCB lines with them. I would first try >>>>> re-soldering that piece first. If this doesn't work, then an alternative >>>>> solution would be to use the through-hole connectors for the antenna. It >>>>> should be located near the MMCX connector. >>>>> >>>>> Using the through-hole connectors may be a little bit tricky since the >>>>> antennas have an MMCX connector attached to the end. You may want to try >>>>> making a very simple dipole(you won't get as good of a performance as the >>>>> actual antenna because of impedance mis-matching) using a wire of the >>>>> appropriate length, or you can use one of the female MMCX connectors to >>>>> interface with the through-hole connector and the existing antenna. >>>>> >>>>> Let me know what happens, >>>>> -Paul >>>>> >>>>> >>>>> On 12/22/2009 10:23 PM, Mohammad S. Hashemian wrote: >>>>> >>>>> 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 >>>>>> >>>>> >>>>> >>>>> >>>>> >>>> >>> >>> >>> >> >> >> -- >> Mohammad S. Hashemian >> Research Scholar/DISCUS Lab >> Department of Computer Science >> 254.2 Thorvaldson Building >> University of Saskatchewan >> (306)966-1947 >> >> > > > -- > 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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