Yes, the standard multimeter can be used. Thanks, Nilesh On Jan 12, 2008 12:50 PM, Tal Rusak <[EMAIL PROTECTED]> wrote:
> Thanks for your advice. How did you measure the power on the USB > ports? Is this with a standard multimeter? > > Thanks, > Tal > > > > > We use the first one (pro connect) for the hub. > > We think that this is better than the other two types of hubs that > > we've tried, but we cannot say whether this is 'the best'. > > > > Regarding the extension cables, I don't know the manufacturer, > > and we were not really suspicious about them as long as we > > use only one. The problem occurred when we extended them with > > two or more cables; measured voltage drop. > > It will be interesting to hear from you whether specific > > manufacturer matters for the usb extension cables. > > > > b.t.w, you can try measuring the output voltage at each usb ports; > > - one on your pc, end of extension cable, a port on the hub... > > bad hub may give too high or too low voltages compared to your pc. > > > > Thanks > > > > - jpaek > > > > > > Tal Rusak wrote: > >> I have done some further testing about this issue. Even with USB > >> extension cables (that otherwise work fine), there are some problems > >> still. For example, I had one telosb mote that inexplicably stopped > >> receiving packets from the PC after about 15 minutes in one try, > >> although it work without failing for over an hour on another trial. > >> I am wondering which Linksys router you ended up using: > >> > http://www.linksys.com/servlet/Satellite?c=L_Product_C2&childpagename=US%2FLayout&cid=1115416907197&pagename=Linksys%2FCommon%2FVisitorWrapper&lid=0719746152B04 > >> or > >> > http://www.linksys.com/servlet/Satellite?c=L_Product_C2&childpagename=US%2FLayout&cid=1115416907844&pagename=Linksys%2FCommon%2FVisitorWrapper&lid=0784446152B06 > >> Also, did you have success with extension cables from specific > >> manufacturers? > >> I appreciate your continued help in advance. > >> > >> Thanks, > >> Tal > >> > >>>>>> - Your usb hub is bad? we had to buy three different types of usb > >>>>>> hubs, just to find a good one. > >>>>>> And at least for me, I see more problems when I use an usb hub. > >>>>> Unfortunately, due to the physical construction of my PC's, I > >>>>> need > >>>>> to > >>>>> use some sort of hub or extender to actually connect the motes. I > >>>>> will > >>> try to find another PC where this is not the case. However, I did try > >> multiple types of extender cables and hubs and the problem seems to > >> repeat on each of them. > >>>> I am not so concerned about the cables as long as you are not > >>>> connecting > >>> several cables in serial (you can see noticeable power attenuation if > >> you connect several cables in serial), but the hubs do matter. > >>>> Don't trust any cheap hubs. Dlink was not so great. Linksys 4-port > was > >>> what we ended up using, but still not as good as no hub at all. > >>> > >>> Thank you for your reply. > >>> It appears that several hubs and a certain extension cable were > at > >>> the > >>> heart of the problem. With appropriate USB connections, I was able to > >> get TestSerial working in both directions for up to 1000 packets. I > will > >> do more stress testing with TestSerial and more complex applications in > >> the next few days. > >>> While the extension cable was probably defective, the hubs appear > >>> to > >>> work well with other devices. Do you know why some hubs have such > >>> issues > >> with telosb motes? > >>> Thanks, > >>> Tal > >>> > >>> > >>> > >>> > >>> > >>> > >> > >> > >> > >> > > > > -- > > Jeongyeup Paek > > Ph.D. student > > Embedded Networks Laboratory > > Department of Computer Science > > University of Southern California > > http://enl.usc.edu/~jpaek <http://enl.usc.edu/%7Ejpaek> > > > > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > -- Nilesh Mishra Embedded Networks Laboratory University of Southern California, 3710 S. McClintock Avenue, Ronald Tutor Hall (RTH) 418 Los Angeles, CA 90089 mail: [EMAIL PROTECTED] [EMAIL PROTECTED] [EMAIL PROTECTED] ph: (213) 821-5627 (lab) (626) 226-7463 (Cell)
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