Espruino Pico and SD cards

Hi there !

-> last message here:
I consider starting a new thread aimed at my project/its needs, not to polute too much the current one & later easier to rework for a tut ;p
Still, some of the following is relevant to the SD card question(s) ( particularly for the 2nd link posted in "the good stuff" )

This being said, onto the good stuff, as well as few important questions I have left after re-re-reading the Pico documentation ;)

-- the good stuff --

• For the pull request, it's just a quickie summarizing infos from the current thread, I hope it'll help ;)

• I'll add an Espruino Pico component to 123DCircuits based on your Eagles as soon as I have time to :)

• I wrote an update to the "Single Button Combination Lock": it now accepts multiple codes + additional tweaks :)
  the code is here, as well as a quite-detailed doc on usage & debug colored output in browser:
  https://github.com/stephaneAG/Espruino_tests/tree/master/SingleButtonCombinationMulticodesLock

• I also wrote some test code to "update"/"restore" config params ( read: vars ) & then reinit the Espruino.
  If on any use, you can find the code here:
  https://github.com/stephaneAG/Espruino_tests/tree/master/UpdateRestoreFlash

-- the questions left / thoughts on previous answers --

1. for the WiFi + SDCard, we agree, I just have to solder precisely enough to use USART2 ;)

2. for B3/SPI1SCK, I thought it could have side-effects as it's the clock line of the SDCard in my setup .. and I must admit I'm wondering how to have 3 different SPI devices connected if some pins have both SPIMISO & SPIMOSI or other "combo" ?

3. I did stumble upon the Pico-FET tut when looking for how to play PCM/PWM audio on the Espruino, and now that I have read it entirely + Pico#Power, I have yet more questions ..

4. I did not look long/good enough to find an example for the "deep sleep" functionality, a hint ?

5. Is it possible the "reset" the Espruino without losing all previously saved stuff ( aka power off then power on, to trigger onInit(), .. ) ?

6. If it's not possible, I guess a cap + a transistor & a pin to short it to Gnd 'll do the trick ?

7. In the same vein, is it possible to save stuff to flash without re-initiating ( aka, 'save()' specific stuff / entire stuff without then triggering 'onInit()' ) ?

8. Am I right to think 'save()' re-init but doesn't reboot ?

9. For B0/FET: when you talk about "monitoring the battery charge via software", have you an example of how to do so ?

10. Still for B0/FET: we can have our own battery charging circuit* before VUSB
    with B0/FET shorted & no software-based battery charge monitoring, right ?

11. I've seen some 555-based circuit that 'd charge a battery when it's below a certain threshold ( not that I implemented one yet :| )

-- main subject/goal --
( see images attached )
After stumbling upon a post on HaD, on hacking intercoms, I wondered if mine was also hackable, in which case I couldn't not pack-a-punch it :P !
Thing is, my configuration seems different than other intercoms, & not all infos I need were provided, so I wrote myself a quick doc' :)
Now, while I can successfully trigger the opening of the ground floor door when ringing the intercom, I still have some guesses on some parts of the circuit:

• using an external 5V power source is possible, but really not handy considering I have no socket near my appartement door. Using the 12V power source from the door opener ( "AP" ) seems a good solution, but I have to keep the Pico running while a relay shorts said-"AP" to Gnd, to open the ground floor door. In your opinion, will the circuit work as expected ( schematic n°1 ) ? any hint on some secure values for the components involved ( here, the cap & resistor ) ?

• to get the Ringer not to kill a pin, I'm currently using the schematic n°2 to clamp a maximum voltage from the [3..10]V that's coming from the Ringer to an acceptable digital 1 ( aka, at least 2.5V). While it seems to work, I'm a beginner in using zeners, and after looking at the Pico#Power diagram, I wondered if a Schotty could be used instead ?

• to be able to output some sound to the ground floor speaker, I may need to "rebias" ( right ? ) the circuit of the original mike ( that's off when "P2" is not pressed ). Here, while I don't know exactly how this part of the hack is done, I bet the transistors used in the schematic n°4 are used to vary the voltage on an already "middle"-d voltage ( when "P2" is pressed/simulated ) or also adjust the voltage to half the original one & wire that to the mic + ?

• the schematic n°3 pictures both the circuit explained in Pico-FET & the one you advised: is the second correct ?

• last but not least, when you talk about "cheap audio modules", are you including single transistor amps circuits, LM386 & Cie or more advanced ICs ? these could run from any pin, without the need to short B0/FET, as for the said-"audio modules" I guess ?

• [ I can't help it ;P ] do you know if it'd be theorically possible to use a mike & speaker as not-ultrasound "disturbance sensor" echo/ping ( using FFT ? ) ? ( aka know if anything stands in front of / near a mike/speaker combo that'd face a wall at like ~2.5 meters )
  ( yes, goal 'd be to sense when someone is/stays before the intercom for some amount of time & play a not-creepy mario sound to help her waiting ^^ )

Thanks in advance for your help, as always useful,
Looking forward to reading from you on this, & hoping the repo's code 'll be of any use ;)

+

ps: as you'll notice in the pics, the relay is quite bulky for the available space: I plan to switch it with a a MOC3041M + BT138 or just a TIP120 if it's fine, but I'm less familiar with TIP120 & the said stuff than my little NPN/PNP PN2222/2N3904/2N3906 :/
=> "time 'll help" ;D
ps2: the video shows the current state of the project running on an Arduino: it hasn't been tested yet on the Espruino & I don't wanna fry it ;p