I am currently trying to build an inertial mocap suit for my own game and media production, so I was looking for PCBs and microcontrollers for awhile but I am new to this that I am still learning terminology, circuits and anything new that would have me stuck. I decided to go for Raspberry Pi 4 8gb as my microcontroller, assuming it would need power for processing the movement data from several IMU, but I also have Arduino GIGA R1 WiFi to have performance comparison and Sparkfun 9dof ICM-20948 as my candidate for IMU, which seemed decent in sampling rate and data output rate and supports SPI signals which would have much faster frame rate than I2C would.
But I realized that it would need MUX to have inputs to be delivered to Raspi or Arduino if I were to have at least 15 IMUs to read mocap data from IMU on joints, thorax and more (ex. 3 on each arms, 3 on each legs, one or two on thorax, 1 on head).
I've been searching for proper candidates for 2:1 and 4:1 MUX candidates that support SPI signals with bandwidth at least 30 Mhz but not many places indicate whether they support SPI signals or not. I may have to stick to I2C but I would really prefer to use SPI for faster motion response. Can anyone recommend me 2:1 and 4:1 MUX supporting SPI signals with bandwidth of at least 30-40Mhz? I really don't know where else to ask this. Sorry if I am not supposed to be asking this kind of question.
Ive read that SPI is a bus but I was thinking minimum 15 IMUs on one microcontroller sharing the pins would be lots of burden that multiplexer could alleviate it. Is it possible for Arduino board I have (or the Raspi 4 8gb) to handle such amount of devices simultaneously through SPI smoothly without multiplexer? I clearly should study more about the bus.
It's problematic, in fan-out of the nodes and overall speed. 30-40MHz along your arms may affect electronics nearby. Apart from that the IMU is limited to 7 MHz SPI. At least 15 SPI slaves on a 3.3V high speed SPI bus are not very common, you'll have to find out more with your specific hardware.
When using non common acronyms spell them out the first time. IMU ( Indiana Memorial Union) I believe is not what you are talking about or many others such as the International Mathematical Union (IMU ).
I suggest you rethink this and post an annotated schematic showing all connections, power, ground and power sources. Links to technical information on the hardware devices is advisable.
I think he has provided enough information about its IMU:
IMO that's too early for the current project state. Every contributor to this topic should know how to attach devices to an SPI bus, but without a specific MUX selected any detailed circuit diagram is moot. It may become of interest later, in case of hardware problems.