Dear all, The problem is solved as far as it can be solved. It is not a power stability issue as I thought it was although it was not far from it. The specific microchip sensor itself needs grounding when it is used in a battery powered situation. Unfortunately that was not in the datasheet of the sensor that I used but it was found in a similar device's design guide: http://ww1.microchip.com/downloads/en/DeviceDoc/40001716C.pdf (page 23 if you are interested). Luckily the sensor will be used in the proximity of a decent amount of brass (trumpet) so my problem is more or less solved.
Thanks for paying attention if you did. Best, Hans. Op vrijdag 13 maart 2020 17:41:00 UTC+1 schreef Hans Leeuw: > > Dear all, > > I am not completely sure where my problem is but I think I have narrowed > it down to its core and it seems to be a power (stability) issue. Solving > it might be a hassle but maybe you can help. > > I have a 3Dtouch sensor from microchip: > https://www.microchip.com/DevelopmentTools/ProductDetails/DM160225 > And I also have a Wifi USB dongle from Edimax: > https://www.edimax.com/edimax/merchandise/merchandise_detail/data/edimax/global/wireless_adapters_ac1200_dual-band/ew-7822ulc/ > > Both are connected through USB to the beaglebone, the 3Dtouch on bus 002 > (the USB bus on the pins) and one on bus 001 (the micro USB OTG connection) > using a micro USB to USB A female adapter. > > The board is powered with a duo cell LiPo using a step down regulator from > Pololu (5V, 5A) on Vin and VB and Vin-USB (pin 1-1, 1-5, 1-7). > > Sensordata from the 3Dtouch gets distorted by the Wifi dongle and I > suspect that interference on the power bus is the cause of it since a > stronger power regulator does help somewhat in stabilizing the issue. > Furthermore using a USB extension cable on the USB wifi dongle reduces the > problem substantially. Such a cable on my project would aesthetically and > practically not be preferred though. From the schematic of the board I see > that USB1 and the micro USB are connected with a ferrite bead (FB1). > > > 1. Would it be an option to remove FB1 and power USB1 separately from > the microUSB? > 2. Would it be possible then to power the USB bus 002 with the sensor > board on pin 1-5 and 1-7 and the rest of the board including the micro USB > bus 001 through V1-1 with a separate power supply (separate power > regulator)? > 3. Should I also do something with Vbat? > > And of course would that probably solve my problem? Or does someone else > recognize my issue and has a better solution? > > Thanks for paying attention. > > Best, Hans. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/e12ae40b-59d0-4586-866f-b5e9ccf40e93%40googlegroups.com.
