Open your shimmer, reseat the 9DoF board. You should get magnetometer data using stock FW and shimmer connect when following the quickstart in the manual. If that fails, email [email protected] for further assistance.
-Ben On Tue, Jul 24, 2012 at 11:33 AM, Mikko Rasa <[email protected]> wrote: > I tried various sample rates between 5Hz and 50Hz. I'm using the > accelerometer and gyro, so six channels in total. If I enable the > magnetometer channels, I don't get any data; I guess the device is unable to > read the sensors. > > I have two Shimmer modules at my disposal, and am testing with one at a time > for now. In the final application I hope to use two or three > simultaneously. I have a WLAN, a couple of wireless mice and a BT-enabled > cellphone here as well, and of course my laptop which I'm receiving the data > on. However, when I tested rfcomm between the cellphone (N900, running > Linux) and the laptop, I was able to transfer large amounts of data without > any errors (several kilobytes; I'm lucky if I get 100 sequential error-free > bytes from the Shimmer). > > This is stock boilerplate firmware, aside from whatever hacks I've put in > while testing and might not have reverted fully. I also tried the official > firmware from shimmer-research.com (in case my build environment somehow > introduced errors), but it has the same problems. > > The problem seems to be very data-sensitive; If I turn the Shimmer to its > side so that the X axis accelerometer gets a low value, I receive almost no > zero bytes at all, and when I do manage to receive a valid packet (i.e. a > zero byte followed by 14 non-zero bytes), the contents are badly mangled. > > Mikko > > > On 24.07.2012 18:11, Benjamin Kuris wrote: >> >> What sample rate and how many channels? >> How many devices in your piconet? >> Any other RF in 2.4GHz band? >> >> Are you using stock boilerplate data packets or are you sending full >> ACL packets (~128bytes data) to minimize BT overhead? >> >> Typically you don't need to mess with the baudrate but minimizing BT >> overhead will improve results if you can accept a little bit of >> latency. >> >> I'm sure others will chime in. >> >> -Ben >> >> On Tue, Jul 24, 2012 at 10:57 AM, Mikko Rasa<[email protected]> wrote: >>> >>> I'm trying to use a Shimmer 9DoF sensor with the boilerplate firmware, >>> but >>> bluetooth transmission is giving me a hard time. It's dropping a lot of >>> bytes, making data streaming unreliable and certain commands unusable. >>> In >>> particular, I can't get an intact reply from the inquiry command to >>> discover >>> the order of channels being sent, so I have to hardcode this into my >>> program >>> based on the boilerplate sources. With the data packets I could use the >>> packet identifier to synchronize the stream and throw out any truncated >>> packets; this might spuriously reject good packets if they contain >>> embedded >>> zero bytes, but I estimate I could recover around 80% of the packets this >>> way. >>> >>> Is there anything I could do to improve the reliability? I've already >>> tried >>> different sampling rates, as well as messing with the baud rate used >>> between >>> the MSP430 and the BT module. Neither of these seems to have any effect >>> on >>> the reliability, unless I change the baud rate so far out of spec that >>> all >>> transmissions stops. >>> >>> -- >>> Mikko >>> _______________________________________________ >>> Shimmer-users mailing list >>> [email protected] >>> https://lists.eecs.harvard.edu/mailman/listinfo/shimmer-users > > _______________________________________________ Shimmer-users mailing list [email protected] https://lists.eecs.harvard.edu/mailman/listinfo/shimmer-users
