RPi 3, Hifiberry AMP2, rotary encoder, on/off switch

[breizheau]

Thank you for the tips an remark.

So i need 5VDC relay (i have some) who will be fed by the 5VDC of the USB port.

I start to understand....

The RPI is switched OFF :
- no 5VDC at the output of the USB port
- the RED LED is fed by the 5VDC of the GPIO to show that RPI is OFF or not started yet
- so the relay is OFF, the only thing you can do is to feed the P6 (RUN) contact to "reset" the RPI and start it

The RPI starts after pushing the momentary switch :
- the RED LED is still RED until the GPIO26 (for you) is fed after the start of the RPI

The RPI is ON :
- the relay is fed by the 5VDC of the USB port, the contacts switch
- the "momentary button contact" of the relay switches so P6 (RUN) cannot be fed by doing a mistake
- the "LED contact" of the relay switches so the RED LED is not fed anymore but the GREEN YES
- the only action you do is to switch off

Very clever !!!!!!

I think this function can be be done easily with the Runeaudio GPIO addon (see the attached file)

[pez]

[breizheau]

I have a small well integrated +5VDC PSU in a box and i think i'll use it. No need to have an overkilled one for this function !

I have to build a pretty nice one (16 or 18VDC) to power the AMP2 'coz i don't want to use a laptop switching PSU.
I did few years ago DIY my own amp, DAC (external, balanced ouputs, modified output stages with Beyerdynamic microphone transformers and symetric chips, a nice job based on "almost ready to use" project).

I have to check my boxes to find transistors, resistors, relays and so on. I think i still have audio grade toroids transformers with multi outputs.

For the hardware part, i have good skill.
But i'll need help for the software part...... To be honest, i have no idea HOW to integrate your code lines in Runeaudio !!!!!

I have only succeeded to activate the add-ons option with SSH connection and copy/paste. That was for me a challenge !!!!!

I have to find out my encoders. I'll take photos to show what i have and what i'll like to do.....

[sonycman]

Merry Christmas to you, guys!

pez
Can you, please, show me contents of the hw_poweroff.py script?
Very interested in making a solid case with power supply for my RuneAudio RPi3 so that it could power on/off (completely cut off the power from RPi) by the front panel button.

Your schematics was very helpful, thanks again!

[pez]

[hondagx35]

[sonycman]

[pez]

[gasket]

Hi and sorry to return to this older thread. But I'd be interested to build @pez 's circuit. Judging by the schematic, I'll need:
- R1: 3k3
- R5: 43
- R4: 220
- On-Off-Switch
- LED1: green
- LED2: red
- Relais: FTR-B4G
- Transistor: BC337-40

I'm not so good at reading those things, but I gather that the middle row in the schematic represents the different legs on the relais?

For me it would be really helpful to have another image where I can see better what connects where on the relais. As far as I know, a relais has two connectors which control it and then another few that switch the secondary circuit.

Thanks in advance!

[renansur]

based on some other threads i got that script set up but is that the correct way to do it?