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ocrdu
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Limits to I2C Switching Multipleswitching multiple RFID/NFC Readersreaders with Raspberry Pi and I2C Switchswitch

I am trying to set up an assembly line scenario where an item with and RFID tag is slid across an assembly line to different stations on a table. 

In the image below you can see ID tags A and B as they move across different stations, and are placed over the sensors. The Pi will then send the tag ID and station location over Wi-FiWiFi.

enter image description here

I was hoping to use a number of raspberryRaspberry Pi's and PN532 NFC/RFID Modulesmodules that have both I2C or SPI capabilities.

If I use an I2C switch such as the (TCA9548) could I read up to 8 sensors constantly with one Pi? If I wanted 16 stations with 2 I2C channels would this be possible with one Pi?

And then furthermoreFurthermore, if I were to bit-bang I2C, or added further I2C switches, what becomes the limiting factor for the number of stations? Is it simply the Pi's/I2C max. clock rate to scan time for all stations?

For example, with a max. I2C clock of 400kHz400 kHz and each I2C packet being a max of ~32 bytes. Is, is it ~80uS~80 μs per packet? And then 4 potential packets per scan and 16 sensors - I could cycle between all 16 every ~5ms~5 ms or so?

Limits to I2C Switching Multiple RFID/NFC Readers with Raspberry Pi and I2C Switch

I am trying to set up an assembly line scenario where an item with and RFID tag is slid across an assembly line to different stations on a table. In the image below you can see ID tags A and B as they move across different stations, and are placed over the sensors. The Pi will then send the tag ID and station location over Wi-Fi.

enter image description here

I was hoping to use a number of raspberry Pi's and PN532 NFC/RFID Modules that have both I2C or SPI capabilities.

If I use an I2C switch such as (TCA9548) could I read up to 8 sensors constantly with one Pi? If I wanted 16 stations with 2 I2C channels would this be possible with one Pi?

And then furthermore if I were to bit-bang I2C, or added further I2C switches, what becomes the limiting factor for number of stations? Is it simply the Pi's/I2C max clock rate to scan time for all stations?

For example, with a max I2C clock of 400kHz and each I2C packet being a max of ~32 bytes. Is it ~80uS per packet? And then 4 potential packets per scan and 16 sensors - I could cycle between all 16 every ~5ms or so?

Limits to I2C switching multiple RFID/NFC readers with Raspberry Pi and I2C switch

I am trying to set up an assembly line scenario where an item with and RFID tag is slid across an assembly line to different stations on a table. 

In the image below you can see ID tags A and B as they move across different stations, and are placed over the sensors. The Pi will then send the tag ID and station location over WiFi.

enter image description here

I was hoping to use a number of Raspberry Pi's and PN532 NFC/RFID modules that have both I2C or SPI capabilities.

If I use an I2C switch such as the (TCA9548) could I read up to 8 sensors constantly with one Pi? If I wanted 16 stations with 2 I2C channels would this be possible with one Pi?

Furthermore, if I were to bit-bang I2C, or added further I2C switches, what becomes the limiting factor for the number of stations? Is it simply the Pi's/I2C max. clock rate to scan time for all stations?

For example, with a max. I2C clock of 400 kHz and each I2C packet being a max of ~32 bytes, is it ~80 μs per packet? And then 4 potential packets per scan and 16 sensors - I could cycle between all 16 every ~5 ms or so?

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nk13
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Limits to I2C Switching Multiple RFID/NFC Readers with Raspberry Pi and I2C Switch

I am trying to set up an assembly line scenario where an item with and RFID tag is slid across an assembly line to different stations on a table. In the image below you can see ID tags A and B as they move across different stations, and are placed over the sensors. The Pi will then send the tag ID and station location over Wi-Fi.

enter image description here

I was hoping to use a number of raspberry Pi's and PN532 NFC/RFID Modules that have both I2C or SPI capabilities.

If I use an I2C switch such as (TCA9548) could I read up to 8 sensors constantly with one Pi? If I wanted 16 stations with 2 I2C channels would this be possible with one Pi?

And then furthermore if I were to bit-bang I2C, or added further I2C switches, what becomes the limiting factor for number of stations? Is it simply the Pi's/I2C max clock rate to scan time for all stations?

For example, with a max I2C clock of 400kHz and each I2C packet being a max of ~32 bytes. Is it ~80uS per packet? And then 4 potential packets per scan and 16 sensors - I could cycle between all 16 every ~5ms or so?