[arm-allstar] Baofeng COS without opening the radio

Doug Crompton wa3dsp at gmail.com
Sun Mar 3 22:54:47 EST 2019


 OK Thanks. We are already thinking about laying out a FOB board
specifically for the Baofeng's. Most of the components are already on our
ARA-1 board now and it would be a minimal change to make it work with the
Baofeng's directly.  I want to breadboard it first and we have some
speak/mic cables on order. I would say if all goes well we could have a
product out in a month. The FOB would plug into the USB and a cable would
plug to the FOB and the radio speaker/mic. Very easy for the user. This
will also make it easier to produce the yellow box nodes.

*73 Doug*


*http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*

On Sun, Mar 3, 2019 at 10:48 PM "Steve via ARM-allstar" <
arm-allstar at hamvoip.org> wrote:

> Certainly Doug, that's why I put it out there. Hope it helps. I'm also
> still
> looking at having some boards for just the interface made, if enough
> people
> are interested for me to order 100 I can get them for a little under $4 my
> cost bare board with masks and silkscreen. I tweaked the layout a bit
> today
> and hand made another board with the layout mirrored from the original so
> that the interface mounts over the top of the sound FOB. I'll put info and
> pictures up in the same folder here in a few minutes, look in the
> directory
> with "Flip" in the name. It makes for a much smaller package.
> I'll also put up the laser printer files that can be used to heat transfer
> and make your own boards but it may be tomorrow before I get those up.
> 73's
> Steve - WB4BXO
> -----Original Message-----
> From: "Doug Crompton via ARM-allstar"
> Sent: Sunday, March 03, 2019 2:39 AM
> To: ARM Allstar
> Cc: Doug Crompton
> Subject: Re: [arm-allstar] Baofeng COS without opening the radio
> Steve,
> If this is reliable it looks like a good way to do it. If it is OK with
> you I will add the info to the Baofeng  howto mods.  We also could easily
> produce a board in quantity to do this if there was a demand. I find any
> more that most do not want to turn on (or have) a soldering iron so any
> amount of mods are out of the question. We are currently sourcing two
> models of FOB's, the ARA1 and the ARA1+. Since the yellow box nodes use
> Baofeng radios and are sold in large quantities it might be advantageous to
> build a FOB specifically for those radios using this method. If we test it
> and it works and we decide it could be a product do you have any objection
> to our use of your circuit?
> *73 Doug*
> *WA3DSP*
> *http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*
> On Sat, Mar 2, 2019 at 8:55 PM "Steve via ARM-allstar" <
> arm-allstar at hamvoip.org> wrote:
> > I have put together a little circuit that allows connection to a Baofeng
> > UV-5R HT providing COS without having to open and modify the radio
> itself.
> > This works great for AllStar, packet, APRS, or most anything that
> requires
> > a soundcard connection to the radio complete with COS. I have even used
> > this circuit without the sound card to connect to an RC-210 repeater
> > controller.
> >
> > I built the circuit based on the schematic of the UV-5R but I believe
> most
> > of the Chinese radios will work with it. I have tried it on several
> > different Chinese radios including the Anytone AT-D868UV DMR radio and
> > they
> > all worked fine. However, even though these radios are mimicking the
> > Kenwood two prong speaker/mic connector, this circuit will not work on my
> > Kenwood TH-F6. This is due to the fact that the Chinese radios do not
> > block
> > the DC of the audio amp from reaching the headset, which is why you hear
> a
> > pop when the squelch opens and closes on these radios, and is what this
> > circuit counts on to turn on Q1 and provide COS. The Kenwood doesn’t work
> > (or have the pop) because it has a blocking capacitor and an MOS switch
> in
> > the audio line that prevents the DC from coming out the jack. But I’m
> much
> > happier using a $35 radio for this purpose anyway.
> >
> > I’ve hand etched a couple of boards for it so far and may send it to a
> > board house to make some prettier boards, especially if others are
> > interested in it (I’ve already quoted them and its just too pricey for
> > small quantities, which is why I decided to hand make the few I needed).
> > The boards I have made have some extra pads on the end to allow soldering
> > directly to the audio jacks of one of the EBay sound FOBs, just makes it
> a
> > bit cleaner than having to cable that side of it, though it still
> requires
> > the two jumpers to the GPIO lines on the sound chip. Also note that there
> > is an extra connection at Pin 4 on the sound card side that should allow
> > using with an RA-35 or similar that already has the open collector driver
> > for PTT. I have not tried this on an RA-35 but feel confident it would
> > work, my target was primarily the CM108 open board sound FOB you can get
> > on
> > EBay and Amazon.
> >
> >
> https://www.ebay.com/itm/CM108-USB-Drive-Free-Sound-Card-Laptop-Computer-External-Sound-Card-Module-New/263928310585?hash=item3d735a6b39:g:SSwAAOSwEVlcDcAU:rk:1:pf:0
> >
> > Also note there is no activity detection nor time out timer in this
> > circuit, so I leave the TOT of the attached radio set to something
> > appropriate in case things get hung up in transmit. And as with other
> > interfaces, make sure to keep the RF from the attached HT from getting
> > back
> > into the RPi.
> >
> > Schematics, some pictures, and this doc can be found here, hope it helps
> > someone.
> >
> https://www.dropbox.com/sh/lrv9uwkgx8tpm6y/AAD2syTNpZDwcjX1gA8zjV9Va?dl=0
> >
> > Steve – WB4BXO
> > http://www.stevemobley.com
> > _______________________________________________
> >
> > ARM-allstar mailing list
> > ARM-allstar at hamvoip.org
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> >
> > Visit the BBB and RPi2/3 web page - http://hamvoip.org
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