staticintlucas / goldfish

A small, thin, USB-C, Pro Micro compatible microcontroller

Goldfish v2

Note

The main branch contains the design for Goldfish v2. The Goldfish v1 design is available in the v1 branch

Goldfish is a Pro Micro compatible microcontroller board designed for use in mechanical keyboards. It is based on the same Atmel ATMega32U4 chip and is programmable using the Arduino IDE or a keyboard specific firmware such as TMK or QMK. Of course it is perfectly usable for any other electronics projects too, not just keyboards.

Links

• PCB Source Files

• Schematic

• BOM

Features

• Lower board profile with the mid-mounted USB-C connector
• Two internal pins make the USB data lines easily accessible
• USB-C is more durable, reversible and just plain cool
• 5 additional pins on the bottom edge of the board
• Pin-compatible with the original Pro Micro
• Sturdier through-hole USB connector
• On board ESD protection for USB lines

Changes compared to Goldfish v1

• Addition of on board ESD protection and fuse
• All 0603 resistors and capacitors for (slightly) easier hand assembly
• Castellated edge connectors similar to the Elite-C
• Less obscure USB-C connector
  • Use of more commonly available components in 2022
  • Choice between multiple compatible connectors and suppliers
  • Uses USB 2.0-only connector for easier and cheaper assembly

USB-C Connectors

Manufacturer	Part number
Molex	216990-0001	-	216990-0003	216990-0002
HRO	-	TYPE-C-31-M-13C	TYPE-C-31-M-13B	TYPE-C-31-M-13A
GCT	USB4520	USB4510	USB4505	USB4500
Approx. thickness 1.2 mm PCB	3.2 mm	3.2 mm	3.4 mm	3.6 mm
Approx. thickness 1.6 mm PCB	3.2 mm	3.2 mm	3.8 mm	4.0 mm

Limitations compared to a Pro Micro

• No onboard RX, TX LEDs
• No onboard voltage regulator (this makes no difference for keyboards; a regulator is only required when power supplies of over 5.5V are used)

Vendors Selling Goldfish

Goldfish v1 rev. C

• BeeKeeb

Comet (modified design based on Goldfish v1; see related projects)

• Tokas' Kable Works

Note: These products are sold by 3rd party vendors and are not 'officially' endorsed by me. I'm simply listing them here for convenience.

(Also please let me know if anything is missing from this list)

Related Projects

Alvaro by Ariamelon

• A modified Goldfish v1 using 0603 components instead of 0402

Comet by Tokas

• A modified Goldfish v1 using a HRO TYPE-C-31-M-12 connector

Whale by Jia Geng Chang

• A modified Goldfish v1 using a Jing 918-418K2024S40000 connector

Goldfish-clone-JLCPCB by Jeremy J Starcher

• A modified Goldfish v1 designed to meet JLCPCB's assembly requirements

Elite-C from keeb.io

• An unrelated and closed source project with similar design goals

(Please let me know if anything is missing form this list)

License

Released under the Creative Commons Attribution Share-Alike 4.0 License. https://creativecommons.org/licenses/by-sa/4.0/

Original Arduino Mini Design by Team Arduino. Arduino Pro Mini Design by Spark Fun Electronics. Pro Micro Design by Spark Fun Electronics. Goldfish Design by Lucas Jansen.

goldfish's Issues

Me brain not so good, gerber file how?

I'm relatively new to CAD and all this stuff, I decided I wanted to commission a PCB so I can handwire my keyboards. I've downloaded Gerber files before but I'm having trouble specifically with this project in which my Gerber files when I plot them on KiCAD. don't actually download as Gerber files and as some other type of file. With that said the PCB manufacturer can't support those types of files. If you can, can you either put a zip of the Gerber files or explain to me what happened? pretty please and thank you for creating this masterpiece of a microcontroller. I don't know if this is the right place to talk about this but sorry if it isn't

New logo for Goldfish

I wanted to contribute to Goldfish I designed a logo for Goldfish. If you like it, I'll send you all files.

Designing a 31-m-13 usb-c version

I was building my own controller using the latest release, but realised that I do not have the Hirose type CX70M usb-C connector. In my region, shipping of this kind of connector is quite expensive.

Hence, I am working on modifying the usb-C footprint to HRO 31-M-13, which can be purchased from aliexpress (see https://www.aliexpress.com/item/32998900371.html?spm=a2g0o.order_list.0.0.31b61802zlAvym for example). Will let you know how it goes.

Question about capacitors on VCC and VBUS

Hi, sorry for opening an issue with a question, but could not find a better place to ask.

I'm an electronics newbie, so it might be a dumb question, but I cannot figure it out. Why are you using 4 x 0.1uF capacitors on VCC and 0.1uF and 4.7uF capacitors on VBUS?

When going through the datasheet for Atmega32u4 I've found that they recommend a 10uF on VBUS (so maybe you have smaller capacitance to improve reset time on reconneciton?). There's nothing about capacitors on VCC.

I've also checked ProMicro schematics, and they have a 1uF on VCC and VBUS connected together.

Sorry if it's a dumb question, but I'm looking into it for few hours already and cannot figure it out.

prototypes / groupbuy?

I found this project via https://geekhack.org/index.php?topic=93571.0, while googling pro-micro with usb-c after breaking my usb port off and having to desolder and re-solder a replacement.

Any chance there will be a group buy or ability to acquire a prototype?

Board from JLCPCB not working

First I would like to say thanks for making such a neat board, I really like it!

For a keyboard project I went to make 20 of these on JLCPCB with their PCB assembly service. I couldn't find the original crystal oscillator, so I had to change it to this.

When the boards came, I soldered the original Hirose connector on but I couldn't get my PC or Mac to detect it at all via USB. I thought perhaps I needed to burn a bootloader, but I'm having trouble using a Nano as an ISP to flash it.

Here is the board, the solder work by JLCPCB and the traces look great.

"Stole" your schematic -- designed a new board

Just letting you know that I snagged a copy of your schematic and used it as the base of a pin-compatible board, but with different design goals.

Right now my project is not an official fork of yours, but that should be fairly easy to do.

If you'd rather I changed the name of my project because it has different goals than yours, I'm more then willing to do that as well.

Of course, either way, full credit will be given.

https://github.com/JeremyJStarcher/Goldfish-clone-JLCPCB

[Question] Changes

Hi,

I'm interested in your design but would like to know how hard it would be to change the design to:
1, include an onboard voltage regulator
2, remove the USB-connector and add soldering points for +5 and GND in in addition to the data-lines

I'm not an electrical engineer and this might be a bit out of my league to do by myself.

Thanks in advance,
Rickard