​​Splitflap large-scale driver project

​​Goal

​​Drive 120 modules easily from a single USB port, with full per-module status feedback.
​​

​​Requirements

  • ​​Drive 120 modules from a single USB port
  • ​​Full status feedback from every module to the controller (error counts and current fault status)
  • ​​Multi-color status LED per module for ease of identifying issues
  • ​​Easy to assemble
​​

​​Nice-to-haves

  • ​​Additional fault monitoring
  • ​​current draw
  • ​​temperatures of drivers and/or a subset of motors?
  • ​​motor supply voltage
  • ​​Cheaper than 10 Arduino Unos + 30 driver PCBs
​​

​​Current Plan of Record

​​Github branch: esp32controller
​​
​​Open questions are checkboxes below.
​​
  • ​​Single ESP32 “master” board
  • ​​Driver board
  • ​​Cables
  • ​​Power
  • ​​12V screw terminal
  • ​​5V screw terminal
  • ​​GND screw terminal
  • ​​Data
  • ​​Clock
  • ​​Motor data
  • ​​Motor latch
  • ​​Sensor data
  • ​​Sensor latch
  • ​​LED
  • ​​Output enable
  • ​​74HCT595 shift registers (2x) + TPL7407L drivers (3x) (pending validation) for output
  • ​​74HCT165 shift register (1x) for sensor input
  • ​​Shared clock line (but output + input separately as half-duplex, so 74HCT165 runs with SPI Mode 2 and 74HCT595 runs with SPI Mode 0)
  • ​​74HCT244 [schmitt-trigger? only on nexperia parts?] buffer (1x)
  • ​​out latch
  • ​​in latch
  • ​​output-enable (w/ pull-up/down to default to off)
  • ​​clock
  • ​​MOSI (doesn’t need to be buffered, but good idea to keep it in sync with clock?)
  • ​​WS2812b leds (4x)
  • ​​12V screw terminals - input + “thru” output for chaining a few together
  • ​​Temperature limits - NTC per motor, alerts in pairs
  • ​​TBD NTC per motor