Talking about destructive effects of ultrasound: I came across a video that claims that babies are born now with geometric 'burn' marks from ultrasonic imaging in utero! Besides that the video says that there is some kind of natural 'sound' or harmonic vibration constituting communication between mother and baby, and that after the ultrasound procedure this harmony is suspended! Sorry for expanding the topic off topic, but You might find this quite important if you plan to have children... Here is the video (very interesting but in German): https://www.youtube.com/watch?v=3DXWWkSudfXl8 On 12/19/14, Jesse Lackey wrote: > Motion tracking, specifically the MPU-6050 from invensense, a > combination 3-axis accelerometer and 3-axis gyro. Most of them were > totally dead, some responded to configuration commands but produced zero > or crazy motion data. > > J > > > > Kardasinski, Milosz wrote: >> Motion tracking MEMs devices or microphones? >> >> -----Original Message----- >> >> Hi all, to elaborate a little further, 30 out of 30 1st-article pcbs >> with the invensense MEMS were destroyed by ultrasonic cleaning of >> the pcb. 100% failure rate of a relatively small sample I suppose >> statistically but way larger than one wants as an engineer trying to >> finish a project. :) The Invensense datasheet warns about this as >> I recall. >> >> I have heard the ultrasonic welding of cases causing grief with MEMs >> and xtals, as people have discussed. For this project, there are 4 >> very small self-tapping screws to close the case, no welding. >> >> That said, pretty clearly other wearable bluetooth devices >> (requiring at minimum an xtal in the 16-32Mhz range, and often a >> 32.768Khz as well if it is bluetooth low-energy) are welded shut. >> What devices like the Fitbit and the like (MEMs and xtals) do would >> be interesting to know. Presumably they have reliably solved the >> ultrasonic damage issue. >> >> J >> >> > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 Tobias Gogolin Tel. D1 (49) 0151 5187 5210 Tel. D2 (49) 0152 0839 5060 skype: moontogo messenger: usertogo@hotmail.com You develop Sustainable Ranch Technology at http://tech.groups.yahoo.com/group/SURA-TECH an Open Source Electric Motor/Alternator at http://groups.yahoo.com/group/Performance_Axial_Flux and an Open Source Motor Controller at http://groups.yahoo.com/group/GoBox --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .