# IRIS Node

![Iris](files/iris.jpg)

![Iris Render](files/iris_render.png)

Designed by [Nick McComb](www.nickmccomb.net) for OSURC Mars Rover.


## Summary

Made for MR1718 as part of the OSU Robotics Club.

Enables a single USB port to act as 10 RS485 Transceivers, receive inputs from an S.BUS style RC receiver, and interface with a few switches. Input power is 24V (self powered, no power is drawn from the USB connection). Features a Teensy 3.2 microcontroller.

This design is entirely Open Source and is available on CircuitMaker, see below for a link to the file.

This is a 4-layer design.

The name "Iris" comes from the greek messenger god, [Iris](http://www.theoi.com/Pontios/Iris.html). This is the board that acts as a "messenger god" for our computer, telling the rest of the robot what to do. 

### Bill of Materials

[Bill of Materials V2](https://docs.google.com/spreadsheets/d/1Z_BUTqAl6qHLze04HCUyY8IqsqWJTmvCWzt6RRplw2Y/edit?usp=sharing)

[Bill of Materials V1](
https://docs.google.com/spreadsheets/d/1TkVeK_GaS78QLqv8NcE_QGGE-NSj-3agn10lKnISSjQ/edit?usp=sharing
)

#### Design files

[MR1718 IRIS on CircuitMaker](https://workspace.circuitmaker.com/Projects/Details/Nick-McComb/OSURC-Mars-Rover-2017-2018-Iris-Board)

### Downloads

[Schematic V2](files/iris-v2-schematic.pdf)

[Schematic V1](files/iris-v1-schematic.pdf)

[3D Model V1 (STEP)](files/iris.step)

### Known Issues

#### Version 1
- Used CAN tx/rx instead of hardware UART
- Connections from FTDI to RS485 transceiver wrong, need to short DE / RE pins together, then this connection goes to FTDI enable. PWREN for the RS485 converted is wrong naming and doesn’t reflect its purpose. No connection to PWREN on 4232 needed...
- Missing 3v3 rail connection to VBAT pin on Teensy. Will program without it, but will not boot without it.
- For R46 vs R47 selection, only R47 is needed.
- No invert needed for S.BUS connection (bridge pins)
- No serial number spot on silkscreen
- No MODBUS ID number spot on silkscreen
- Likely that this should use a high-speed USB hub instead of the current full-speed implementation. It is easy, without deliberate planning, to hit the bottleneck of the USB hub.
- Remove GND connection for RS485 going out of the board (to ensure reverse protection downstream)