Is STEMMA Speaker really STEMMA?

[gallaugher]

Hi!
I have a few of these speakers:

Adafruit STEMMA Speaker - Plug and Play Audio Amplifier
PRODUCT ID: 3885
https://www.adafruit.com/product/3885
https://learn.adafruit.com/adafruit-stemma-speaker

I also have some Grove to STEMMA QT cables:
https://www.adafruit.com/product/4528

While this learn guide says Grover + STEMMA (not QT) are plug compatible:
https://learn.adafruit.com/introducing- ... udio-grove
"STEMMA 4-pin cables are cross-compatible with Grove parts."

I don't see a 4-pin cable on the Adafruit STEMMA Speaker - Plug and Play Audio Amplifier. The cable seems like a 3 pin JST cable & the Grove end of the Grove to STEMMA QT cable I've got doesn't fit.

What makes these speakers STEMMA speakers? I get that they can be connected to a CPB or other device using three aligator clips, but how I I keep them in a STEMMA daisy chain of products, or even better add to a STEMMA QT chain using an adaptor cable.

Thanks for helping me understand what makes this a STEMMA and if/how I can incorporate this into my existing STEMMA QT product mix on any board I'm using STEMMA QT with.
Thanks!
John

[adafruit_support_mike]

We have an article on just that subject over in the Learning System:

https://learn.adafruit.com/introducing- ... -stemma-qt

Short version: it's a connector-and-pinout standard for power and I2C connections. There's also a requirement for level-shifting so you can safely mix 3.3V and 5V devices.

STEMMA and STEMMA-QT are different standards that do the same basic thing. STEMMA uses JST-PH connectors, and STEMMA-QT uses JST-SH connectors. [EDIT 11/2023 by danhalbert:] STEMMA is electrically compatible with Grove but the connectors don't fit together that well. STEMMA is physically compatible with Gravity but electrically incompatible (very different pin order). STEMMA-QT is compatible with Sparkfun's Qwiic standard (as the saying goes, the wonderful thing about standards is you have so many to choose from ;-) Fortunately it's simple to interconnect all the different flavors.

[gallaugher]

Thanks, Mike. I’ve gone through that learn guide, which is quite good. My confusion is with the connection port on this specific device. Despite the STEMMA in the product name, the connector doesn’t seem to be a STEMMA connector, but rather a 3 pin jst. What do I need to do to get this in a STEMMA chain to realize fhr STEMMA in the device name? And actually what I really want is to get it in a STEMMA QT chain but since they are compatible and there are STEMMA to SQT cables I figure that be trivial.

[adafruit_support_carter]

In the case of the PID 3885 speaker, the STEMMA connector is an example of the 3 pin variant:
https://learn.adafruit.com/introducing- ... ep-3035225
which are for use with PWM/Analog/Digital IO.

Only the 4 pin variants are I2C.

You can't mix the two types.

[gallaugher]

Ah - thanks. Now I see. So even if something is old school STEMMA (as opposed to STEMMA QT), it still can't be added to a standard STEMMA / STEMMA QT I2C chain. I'll be sure to keep this in mind.
I've used the alligator clips to get this connected to a CircuitPlayground Bluefruit. I'm assuming I could easily breadboard this to another board, like an Arduino Nano RPCoonnect by attaching a three-pin connector to the board.

Either of these cables would work, depending on if I needed pins for breadboard, or sockets to directly connect to header pins, correct? Thanks again!
https://www.adafruit.com/product/3893
https://www.adafruit.com/product/3894

I like the STEMMA speaker / cable because it's a no-solder option and includes the amp for quick add-in.

I'm experimenting with components to add to my physical computing course & want to make sure everything works. I'm also going to buy some of your amplifiers & speakers to see if I can mock up some decent, low-cost audio components to add to a CircuitPlayground Bluefruit & Arduino Nano RP2040 Connect. Am I correct in assuming that any of your amp breakouts that are in the 3.3 v range should work with these boards? Am thinking I'd get screw-on terminal blocks and solder them in, in advance, to allow students to easily add speakers or connection wires (pins for breadboarding, alligator clips for the CPB). Does it seem I'm thinking about this correctly & that I should avoid any amp breakout that doesn't go down to at least 3.3v (It seems you're got a few 5v ones in the shop & I'm guessing I shouldn't use those since CPB and Nano max at 3.3v). And as for closing speakers - I should make sure they fit in the Ohm / Watt range of the amp?

As an example, if I bought:
https://www.adafruit.com/product/2130
This says "2.5 Watts into 4-8 ohm"
Below are links to three Adafruit speakers that look cool, but each is a 3 Watt speaker. Do I assume they won't work w/the 2.5 Watt amp above, or will they work but just be "quieter" if I use them with that amp.
https://www.adafruit.com/product/1314
https://www.adafruit.com/product/1313
https://www.adafruit.com/product/3968

And if I choose this amp, everything should work fine with those speakers, right?
https://www.adafruit.com/product/3006
I'm also planning on buying this speaker for testing, cutting off the JST, and stripping and sticking the two wires into screw terminal jacks I'd solder to the amps.
https://www.adafruit.com/product/3351
I'm thinking about this correctly, right?
Finally - once I get the breakouts created, they don't require any special resistors or anything, right? Just wire the connections to the appropriate pins in the board (power, ground, and an analog pin) and they'll be ready to go?
Thanks for your patience & helping me thinking through this. I'm very green with audio & don't really understand all of this, so don't be shy about correcting poor assumptions on my part - that's really helpful so I don't go down a wrong path.
Cheers! John