Qwiic / Stemma QT / Breakout Garden / Grove plank

General
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Is there a plank for these i2c connectors? Should be dead simple 4 pins (could add SAO and tildagon hexpansion too for a few more)

If somebody hasn’t already covered it, I can fire up kicad I guess

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This is the first I’ve heard of a desire for such a plank.

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I’ve a small pile of breakout boards with either grove or quiik 4 pin connectors on them - I can connect to them with jumpers but a plank would be faster.

I’ll put something together this week

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I’m definitely interested. I have several Qwicc/Stemma QT adapter boards for my Raspberry Pi collection.

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Great idea. I’d be happy to make one up. What are all the connectors types?

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System Type Pitch Pins Pin order
Stemma-3 JST PH 2.0mm 3 1.GND, VCC, DAT
Stemma I2C JST PH 2.0mm 4 1.GND, VCC, SDA, SCL
Qwiic/Stemma QT JST SH 1.0mm 4 1.GND, VCC, SDA, SCL
Grove HY2.0/A2008WR-S-4P 2.0mm 4 1.GND, VCC, SDA, SCL
Gravity JST PH 2.0mm 4 1.SDA, SCL, GND, VCC
Breakout Garden Edgeboard card connector 2.54mm 5 1.VCC, SDA, SCL, N/A, GND

Does this seem right?

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Included the STEMMA 3 on a pin with PWM and FREQ measurement. But if it is intended to be used with RGB LEDs, then IO0 is probably a better choice.

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Should there be more than one connector for the popular standard like Qwiic/StemmaQT?

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The breakout garden is a PCB edge connector. I’ll need to make a footprint for it.

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With 5 Qwiic connectors.

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The 5 Qwiic version is excellent, but what about reducing the Qwiic numbers by 1 or 2 and adding an extra Grove connector?

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I’ll share my thoughts, respond to your questions, and also list some additional actionable feedback:

Non-actionable feedback

In case you waffle on inclusion of something, here’s my thoughts.

  • GROVE – Glad to see it there for completeness
    • IIRC, I only have a couple boards with Grove. I was unhappy with the custom connector that was almost, but not quite, a standard plug.
  • QWIIC – I had one (maybe two) boards with this early on. I switched focus to STEMMA boards because it’s too easy for me to release the magic smoke by send 5V by accident.
  • STEMMA / STEMMA QT – My favored standard, primarily because to be called STEMMA, the board must be 5V tolerant (3V3..5V).
    • STEMMA QT boards are my primary quick-connect option for prototyping.
    • I also have a few of the larger STEMMA boards.
    • Neither STEMMA connector has any quick-release, so ensuring a little finger space around each port is likely appreciated.
    • STEMMA QT boards often have a daisy-chain option … so port count is less critical.
  • Breakout Garden – This is a new one for me. Is this a popular format? I’m fascinated that card-edge remains a popular connector type. If popular, then I’m glad to see it on here.

Response

I’d appreciate feedback on

  1. Should there be multiple of the common connector (Qwiic)
  2. Worth including the Stemma 3P connector?

Yes, I would have multiple STEMMA QT (Qwiic) connectors. Many STEMMA QT boards have daisy-chain ports, but not all. Maybe reduce to three (or four) ports, to make it more finger-friendly? I imagine I’d have trouble getting all four connectors populated.

I’m abivalent about the STEMMA 3P connector. If it’s included, I’d give it a unique plank IO … not overload with SDA (IO0) / SCL (IO1). It’s useful for buttons and directly driven (PWM) LEDs, but … the value of a standard port is lower than for I2C.

Questions on the GRAVITY port

  • Gravity – Not sure I’m following this one…
    • IIRC, the controller is supposed to use color-coded 0.1" male headers, while the target devices use a connector as shown on the board.
      • Did they update Gravity to have a standard 4-pin connector on the controlling MCU side also?
    • Is the intent of the breakout to emulate a Gravity device?
      • If intended for emulation, maybe have it use a unique pair of plank ports … maybe IO6 and IO7?
    • If not intended for emulating a Gravity device, and they didn’t update the controller side to use similar connector, then I’m not sure I understand this port’s purpose.
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Thank you for sharing your knowledge with us. I concur with all of your points. I’ve definitely learned something from your reply!

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