Hi,
I'm building an internet radio based on Hifiberry Amp+ with Volumio. I want to add a power on/off button to my project and I have found the ATXRaspi board which give this feature to the raspi. Unfortunately it's made to be use with the 5v micro usb and not a 12-18v through Hifiberry Amp+.
Is there a similar card that could be use to have a full on/off power button or have you heard of a similar project that I could re-use?
Thanks for your help.
Unfortunately I don't know anything similar for the Amp. The best workaround is shutting down the Raspberry and then turning off the Raspberry Pi by a normal switch. But maybe someone has a better idea.
Best regards
Daniel
Wondered the same thing. Proper shutdown of a rpi uses a shorted GPIO with resistor with running cron task that submits a shutdown command when the GPIO pin is brought low.
Did this on an amp+ project but solder access to GPIO pins non-trivial.
With all the rpi USB ports I wonder if someone made a USB on/off button? It would be a little USB dongle with a button. This USB button dongle would do well for any rpi user who did not want to solder and would allow any computer with a open USB port to have a programmable "key".
I saw an rpi article were sw was written that senses when the USB device table changes in a specific way. This would work for amp+ users by running a shutdown command when you unplug your USB WiFi dongle. Or one could buy a USB cheap Bluetooth dongle and set that up with this sw and a shutdown command when you pull out the Bluetooth dongle - giving you a solderless shutdown switch for a few $'s.
Shutting down the Raspberry Pi by a button connected the the GPIO is simple. The question is: What do you want to accomplish? If you want to turn of the power, shutting down the Raspberry Pi is not enough. You have to completely cut off the power supply. With the Amp, I would recommend using an external relay for this. Implementing something like this isn't very complex for somebody who has designed some circuits. You can even build this without a PCB.
You can't turn on the Raspberry Pi with something connected to USB. When the Raspberry Pi is powered off, you can't power it on with a device connected to USB - because this device isn't even powered.
Best regards
Daniel
For me it is the USB shutdown button that's needed for a solderness shutdown solution.
Unplugging p/S from amp+ AFTER shutdown powers off amp+&rpi and reconnect amp+ p/S boots rpi. Getting rpi&+ to shutdown from hw USB button is key - and a simple solderless install.
In this case you don't need an USB button. Just connect it to a GPIO. The Amp+ already comes with long headers. You don't need to solder, but can just connect a button with jumper wires.
Best regards
Daniel
I was searching for power switching the RPi2 and AMP+ and I found this site but not AMP+ but DAC, here is the link:
https://plus.google.com/+BertKrus/posts
Tom
Hi,
Thank you for you responses. I've found this diagram of a power controller for the Raspi by MOFSET. It seems that the input voltage could be from 20V to 5V, so I was thinking to re-use it with the Amp+:
Instead of connecting it to the micro-usb, I will connect it to the entry of the Amp+.
What do you think about it? Is it risky for the Amp and the Rasberry?
Thank you for your help.
I don't know this circuits and won't analyse it in detail. Just make sure that you don't get 18V from the power supply to an GPIO of the Raspberry Pi as it will destroy it. If you understand the circuit, you should be able to make sure that this won't happen. If you don't understand the circuits, I would not recommend to do this.
Best regards
Daniel
Thank you for your advice, I will first try to understand how it works and then test it without connection to the raspi/amp.