By experimental method I've determined that one doesn't have to disconnect the batteries while using the powered USB, but your mileage may vary... MS
Eric Keller wrote: > We have been doing experiments with power measurements. What I do > is power through the battery connector unless programming. To program, > disconnect the battery power and hook it up to the usb. It can get > a little tiresome. We removed the battery holder and simply connected > wires to a bench power supply instead. No reason to modify past that. > It's a lot faster to turn the bench supply off than it would be to > remove batteries. > > We also did experiments measuring current using the USB power. > We interrupted the usb ground line and put a 3 ohm resistor in it and > measured the voltage across the resistor. The only problem is that > the usb chip takes a lot of power and it's a leap of imagination to > try to subtract that out of the power calculations. We redid the experiments > without the USB chip, and it was more work but also more satisfying. > > > > On Fri, Jan 9, 2009 at 2:34 PM, Jimmy <[email protected]> wrote: >> Hi, >> >> I am looking for some help regarding the TMote Sky motes. >> >> My problem: I want to simulate the draining battery using external >> circuitry (i.e. using a programmable power supply), but to do that the >> USB power must be cut-off and still need to communicate with the host >> computer. So, I disconnected the 5V power line from the USB cable, and >> when I do that the host computer cannot be able to see the Tmote >> connected to its USB and hence not able to program it. >> >> I also tried to program the TMote Sky when it is getting power from >> 2-AA batteries and USB power cut-off, and the result is that the host >> computer cannot see the TMote Sky. >> >> Is there a way to program the TMote Sky with USB connected and without >> using USB power (5V). >> >> Please help me on this regard. Sentilla has discontinued support for >> the Tmote Sky (http://www.sentilla.com/moteiv-transition.html). >> >> Thank you, >> Jimmy >> _______________________________________________ >> 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 -- Platform: WinXP/Cygwin TinyOS version: 1.x, Boomerang Programmer: MIB510 Device(s): Mica2, MicaZ, Tmote Sensor board: homebrew _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
