What tool for connection diagram - MAX485 I2C PCA9685 MCP23017 ULN2803 JMRI CMRI

I am in process of building a HO model train layout, controlled by JMRI via DCC++ and CMRI. For accessory control, RS485 is used to connect Raspberry Pi 3b to multiple Arduinos (i.e., CMRI). I2C is used to connect PCA9685 modules to Arduinos. Turnout switch machine servos are connected to PCA9685 board. I2C also connects to MCP23017 module with ULN2803 for LEDs and/or relays.

I plan to use available modules as much as possible, but I did not locate them in the parts library. Is Fritzing the right tool to create the connection diagram?

  1. CH340g USB to RS485 485 Converter Adapter Module
  2. MAX485 Chip TTL to RS-485 Module
  3. PCA9685 16 Channel PWM Servo I2C Module
  4. MCP23017 I2C 16bit I/O Extension Module

Welcome aboard! For parts not in the core library a google search of the form “fritzing part CH340g” will often find parts. In this case in this forum post (although I don’t know how usable the part is):

The other parts have similar hits. If the parts you find don’t work, feel free to post with a link to the part and one of us will likely take a look.