[arm-allstar] just getting started and trying to understand the current requirements with a PI2 or similar

[Doug Crompton]

Dave,

Yes, you will need a USB sound interface which can be the $70 DMK URI or a $3 modified sound FOB. A very simple modification and source link for the FOB is in the howto section at hamvoip.org.

Built-in sound would not work. There is no audio input on the Pi and output is normally routed to HDMI but can be routed to a TRRS connector -  http://www.raspberrypi-spy.co.uk/2014/07/raspberry-pi-model-b-3-5mm-audiovideo-jack/

There has been interest in using the GPIO for COS and PTT but the USB FOBS have the I/O also. The modification to bring it out of the FOB is really not complicated. The SAME interface circuitry would be needed if using I/O on the FOB or off the GPIO pins. So it is really not simpler.  So there is no completely easy way unless you buy a DMK URI. 

I suggest you checkout the howto for simple USB sound FOB mod. At less than $4 it is certainly worth a try. You don't have much to lose. If you want to save over $60 and you have some patience it is a fun one night project.

The steps involve opening the FOB, the case piratically falls off. Soldering two small wires to the chip. This is the hardest part but not really difficult. A real easy way is shown in the photos. Solder three more wires onto the connectors. Bring those five wires out in a shielded cable (old usb cable works - 4 conductor and shield/ground) and at the other end wire up the additional interface components either in a small box or in a connector as shown in the howto.
The FOBS reduce to $2.40 in 10 quantities.

I don't have the time but it would be great if someone offered to build these for people who can not. Either partially or completely with a DB25 wired like the DMK on the radio end. The user would just have to supply the 25 pin to radio connection the same as using a DMK URI. Wiring it this way would make it plug compatible with  the URI. I would think this could be done for around 1/3 of the price of the URI. I guess I am dreaming though because there are vendors out there ripping people off for an interface cable and two connectors for $50! 

Hams are cheap and you are right paying twice as much for a sound interface as the main board is a lot and if you have two nodes on one board even more. 

73 Doug
WA3DSP
http://www.crompton.com/hamradio


> Date: Sun, 18 Oct 2015 17:58:39 -0700
> From: david at lang.hm
> To: arm-allstar at hamvoip.org
> Subject: [arm-allstar] just getting started and trying to understand the current requirements with a PI2 or similar
> 
> I see several blog posts talking about using a RPi with allstar that ignore the 
> built-in audio and GPIO pins of the Pi in favor of external interface boards 
> that cost several times more than the Pi does.
> 
> I'm hoping that these were just early attempts and current versions will use the 
> built-in audio and much simpler radio interfaces from the GPIOs
> 
> What's the status on this sort of work?
> 
> David Lang
> _______________________________________________
> 
> arm-allstar mailing list
> arm-allstar at hamvoip.org
> http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> 
> Visit the BBB and RPi2 web page - http://hamvoip.org
> 
 		 	   		  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.hamvoip.org/pipermail/arm-allstar/attachments/20151018/5ee35105/attachment.html>