set pico to sleep, writing playback info first

[pandalanax]

currently there is no support in circuitpython for deepsleep.

blocked by adafruit/circuitpython#9491

corresponding PR: adafruit/circuitpython#10023

[bablokb]

CircuitPython has deep-sleep support already for a long time (but not for the RP2350). The main caveat is that it resets the Pico after wake-up. So depending on what you processor you are using and on what you think "deep-sleep" actually should do, this is true or not.

Since you linked to my PR to add deep-sleep for the RP2350, you might have also read the complete discussion. I still don't understand why the PR is not merged. This seems to be more of a NIH problem, since all the arguments of the maintainers are weak.

I am running all of my systems with my PR and I have not yet encountered any problems.

Having said this: in the context of your code, light or deep sleep will never work. You cannot go to sleep while i2s is playing.

[pandalanax]

Yes, I had some trouble setting up the build environment, but now with your PR, the sleep feature is working as intended. Thanks for your work!
The code is currently more of a rough draft — just stitching things together and exploring if my idea is possible. But thanks for the hint!

[bablokb]

Great! Some minor notes:

• with my PR, you can also use light-sleep. For the Pico2 (W), it is identical to deep-sleep but it does not reset. You need to reconnect after wakeup if you need wifi.
• I suggest that you use the keypad-module for your keys. That module supports interrupts and scans key-presses in the background. You never miss a key press. And the setup and usage is much easier.
• if you want to have really low-power sleep, have a look at: https://github.com/bablokb/pcb-pico-power-switch. With this shim, you are down to below 1µA instead of about 1.4mA that you have with the Pico2-W in deep-sleep. But for this application it is probably not worth it unless you only use the device once a week or so (i.e. you mostly have it off)

I have a very similar project: https://github.com/bablokb/cp-webradio. It does not stream podcasts, but internet radio. Otherwise, many building blocks are very similar.