Re: 12V Power for the Pi (was Re: [RaspberryPi-4-HamRadio] Getting back to the RPi)

Daniel Holmes

That’s my plan—and from what I’ve read they are designed to use the bus correctly. 


. Please pardon any mispelings or errors.

On Dec 24, 2019, at 2:51 PM, Tadd KA2DEW in NC via Groups.Io <tadd@...> wrote:

I wonder if G8BPQ node + TNC-PI can share the i2C bus with the MOPI.

On December 24, 2019 at 1:40 PM, "Tadd KA2DEW in NC via Groups.Io" <tadd@...> wrote:

interesting.  ok.  so same scenario but in B> the Raspberry PI is left OFF.  Does it turn on when G or H?

On December 24, 2019 at 1:36 PM, Daniel Holmes <danielh@...> wrote:

If power is applied to the Pi while it is off it will turn on at G.

Daniel Holmes, danielh@...
"Laugh while you can, monkey boy!" -- Lord John Whorfin

On Dec 24, 2019, at 11:33 AM, Tadd KA2DEW in NC via Groups.Io <tadd@...> wrote:

Using the MOPI-2 In this scenario

A> mains are working.  
B> Start Raspberry PI
C> runs steady for a long time (weeks)
D> Mains go to 0v but are still hooked up.
E> battery eventually gets low
F> MOFI does LInux shutdown and turns off Raspberry PI
G> mains come back eventually
H>  battery charges
J> raspberry is provided power again

Is there a way to have the Raspberry PI come back on-line in H or J ?  

  Tadd - KA2DEW
  Raleigh NC USA

On December 24, 2019 at 11:39 AM, Daniel Holmes <danielh@...> wrote:

Good question on a monitor—I think the specs said it’ll only do about 2.5-3 amps, but there’s a way to switch in a 5V relay to power up the monitor. I personally run my Pi headless, and use VNC on my iPad to connect in (although I have a small wireless keyboard I use because typing on a virtual keyboard stinks.)

Daniel Holmes, danielh@...
"Laugh while you can, monkey boy!" -- Lord John Whorfin

On Dec 24, 2019, at 9:35 AM, Michael WA7SKG <wa7skg@...> wrote:


THANK YOU! What a device! While you say expensive, it's only a few dollars more than the USBuddy and does so much more. The on/off switch is a big plus, as well as the HAT configuration. The only thing I'm not sure of is powering the monitor as well. As I am using the Smarti-Pi Touch Case, the RPi is not mounted directly to the monitor, so it is not powered through the IO pins, but from a separate USB connection. However, I do not think this is insurmountable.

Thanks again.

Michael WA7SKG

Daniel Holmes wrote on 12/24/19 6:57 AM:
For running off a 12V supply, this is what I use: Seems to be pretty RF quiet.
Yeah, it’s a bit expensive, but I have it wired with an on/off switch to power up/power down the Pi cleanly, and it powers it down when the batteries are almost exhausted. I haven’t worked up the battery charger just yet, but it’ll be a handy part of my go-kit. I still need to figure out how to use more than 1 HAT on my Pi, but that’s just a bit of research—so many projects so little time.

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