Suggestions for V2
I just finished installing a SuperGerbil board on a Shapeoko 3 with external stepper drivers. It went well and was pretty straightforward after having already converted this machine to a non-Carbide3D GRBL controller.
1) Add a jumper to connect Switch Vin to PWM Vin, or put all the Vin next to each other so they are easy to jumper together.
2) Add a header with several 3.3v, 5v and Switch Vin pins, Stepper Vin, and grounds (at least 4 of each) Could be just footprint for a .100" header
3) Consistent Vin vs GND on the Vin connectors. It's opposite on the switch Vin vs MCU Vin, and they're right next to each other.
4) Add regulation on MCU Vin.
5) If MCU Vin is regulated, a Jumper to from MCU Vin to Switch Vin would be handy - now one PSU can supply switches, PWM, and MCU without jumper wires.
6) Shorting jumpers on each axis (particularly A and B) switch
7) Switch Vin on a blue input block like all the rest.
8) Turn the mosfets 90 degrees so a single heat sink can be bolted to all of them at once.
9) Label the pins on the pololu motor board connectors - these are the almost the only pins on the whole thing not labeled.
10) The "screwless" flat-pack case is extremely fragile, and "flexy" - a screwed together case (top and bottom with a spacer between) would be adequate, stiff, and use less material.
11) A header for the handy fan included with the case.
12) In addition to the PWM output, a single GPIO output to control a spindle IOT switch. It's (fairly) common to use the PWM to turn an IOT switch on/off to control the router. Being able to switch between the two outputs would be double-plus good. With a laser mounted on the machine it would be nice to set the router off, and the laser (PWM) on and run one laser+cut job hands free. Maybe this is actually possible using the Motor control output on the other side of the board....but if so it's unclear how to do so.
13) A single table of outputs/inputs, what they are for, voltage limits, etc. (pin name, input/output, max voltage, and a short note on purpose for each)
14) A way in software to "join" two stepper drivers - for a double stepper Y axis (Shapeoko 3) this is helpful. Avoids running two steppers from one driver, cutting the available current for each stepper in half.
15) A regulated 12V power supply available if the motor Vin is connected and located next to each switch input for proximity switches instead of mechanical switches would be nice.
16) If the documentation pointed to this page, I think people would appreciate it: https://github.com/gnea/grbl/wiki/Grbl-v1.1-Configuration
17) Pretty much every HC5/HC6 Bluetooth module I can find has male pins, which isn't a great match for the male pins on the board. A female connector on the board would be preferable.
Here are some updates.
How to get a HC-05 (off the shelf) to work with your supergerbil board. DO NOT attempt to use an HC-06 board set, that's just a ton of hassle you don't need, and they cost the same. The HC-05 board is the one you want. I suggest using an actual DSD-TECH branded board, rather than saving $1 for a clone board.
1) You need to make a cable to adapt from the pins on the hc-05 board to the supergerbil board. Pinout is 1=vcc 2=tx 3=rx 4=gnd
Connect pin 2 (tx) to the RX pin on the hc-05.
2) Use the dsd-tech tool (under windows) to set up the adapter. Get it here: http://www.dsdtech-global.com/2017/11/dsd-tech-bluetooth-config-tool.html
3) Get a dsd tech usb->ftdi->ttl serial adapter. They call it a SH-U09F (amazon)
4) Use the adapter connected to the bluetooth module, connect at 9600 baud (the default) Then press the button on the HC05 module and then "test" in the tool. You should see "ok". Set the name to something you can remember, the pin to something you can remember, and the speed to 115200. (press the set button on the screen for each).
5) You're now done with the ftdi tool, the dsd tech software.
6) Connect the bluetooth module to the supergerbil board, and put the jumper on.
7) Connect w/ bluetooth to the module - it should have the name you used in step 4. If it doesn't go back to step 4.
8) Use your sender software to connect to the supergerbil board at the new com port that will show up in the options on USG. If you see two "new" com ports show up, use the lowest numbered one.