Wiring Schematics Redux

[maxsu]

In issue #18 @bestjinx asks whether there is a circuit schematic for doggo. In issue #20, @HelloPlanet contributed a tentative pinout. I'd like to address the lack of schematic, and propose a way forward towards a community contributed schematic.

In particular, I'd like to entertain the theory that:

1. There has simply been no need for a formal cad schematic so far / a schematic has been considered out of scope
   • The system uses a breadboard, and has a pretty simple communication pin layout which is encoded in the firmware
   • This would be clear to the designers and people conducting a serious review
   • A schematic would however be a great benefit for hobbyists / students
   • But! Tt would be a substantial labor
   • As such it may be out of scope for doggo designers' current goals

Continuing this line of thought:

2. We may have an opportunity to contribute a cad diagram as a community. Some notes towards this:
   a) The teensy's pinouts for the AS5047D-TS_EK_AB IMU are mapped here. Note that the current generation doggo BOM does not include the IMU.
   b) Teensy -> Odrive serial ports get mapped here.
   c) The Xbee is connected to the Teensy via the teensy's USB host port, and simply relays USB serial commands to the Teensy (see this)

3. Last, but certainly not least, the electrical diagram we find in the Doggo Paper shows us that b) and c) are the only data connections in doggo. The rest of the connections are power connections that we can infer with relative ease.

A formal CAD model would be a crucial step in reducing hobbyist/student expertise barriers, and would open the way for a fully integrated open source circuit board with no breadboard component.

@bestjinx, @kigerzh, @HelloPlanet - Would you three be interested in helping an effort to reverse engineer the circuit schematic, if necessary?

@Nate711 @CrazyAZ - what would you guys recommend here? Can we get your blessings on an open schematic for doggo?

[maxsu]

Next steps:

1. Agree on a primary file format and circuit design software (eg. .SCH + KiCad, Autodesk Eagle, etc.)
2. Add part IDs to the electronic parts in the BOM
3. Import component pinouts into PCB-CAD
4. Build the component netlist
5. Layout and annotate the schematic, title block, etc
6. Version and commit the schematic to the project.

[Nate711]

Hi Maxsu, thanks for opening this issue. If you guys want to make a schematic we'd love it and would happily check it. We are unfortunately maybe too busy to create as nice a circuit design as you might like. However we could make a pin-to-pin table of connections if that would suffice.

[niranjan1997]

Hi Nate, it would be great if you can provide the pin to pin table