[arm-allstar] A simplified USB FOB modification

Peter Kendall g7rpg at hotmail.com
Thu Jun 25 09:38:57 EST 2015


I've made a quite a few micro nodes for friends, been using £1 sound 
cards from eBay/China

There is no soldering required to tiny surface mount parts.

I use a gpio pin from the Pi to drive PTT directly on the BF888, this 
works ok for the low voltage sets, for 12v radios I use an opto coupler 
or mosfet (2n7000) to keep the pi gpio safe.

COS (pull to ground) to the volume down button.

PTT works using the events subsystem and a little program I wrote to 
pull the gpio pin (wiringPi 0) to ground.

;
; rpt.conf for Pi PTT
[events]
/usr/local/sbin/gp0on = s|t|RPT_TXKEYED
/usr/local/sbin/gp0off = s|f|RPT_TXKEYED
;
;

Have a look at my (cluttered) flickr site, some pics of the various builds.

Blob fob with PTT (yellow) going to gpio pin of pi

https://www.flickr.com/photos/127794264@N08/18126465794/in/datetaken-public/

COS example
https://www.flickr.com/photos/127794264@N08/17197162979/in/datetaken-public/

Example node with 'blob fob' and pi PTT
https://www.flickr.com/photos/127794264@N08/18458513778/in/datetaken-public/

Hope this maybe of some use?

If anyone is interested I can email the two little programs gp0on and 
gp0off.

Peter
G7RPG
Node 41689


On 25/06/2015 15:04, Doug Crompton wrote:
> Jim,
>
>  I understand the desire to try to put all the parts on the board put 
> that is often a recipe for disaster and so much harder for most 
> people. Absolutely minimizing what you do to the board is the best 
> approach. I have done it both ways and cutting things or de-soldering 
> things often leads to problems so when I realized how easy it was to 
> do it this way I wanted to share it.
>
> *73 Doug
> WA3DSP
> http://www.crompton.com/hamradio*
>
>
> ------------------------------------------------------------------------
> Date: Wed, 24 Jun 2015 23:39:30 -0700
> From: jim.pilgram at gmail.com
> To: arm-allstar at hamvoip.org
> Subject: Re: [arm-allstar] A simplified USB FOB modification
>
> I've had better luck on the switches using a nipper and just simply 
> cutting the 4 corners at the board. The less you have to put the 
> soldering iron on the board, the less chance of lifting a trace. I 
> also use the nippers to cut off all the jacks. All parts go on the 
> board and a 5 conductor cable is fed out one of the jack holes in the 
> case. I use super glue to weld the buttons on the cover in place and 
> reuse them. ‎I've made about 25 of these to date for myself and our 
> group. We are using primarily CDM series Motorola simplex nodes and I 
> put them together including the motorola 20 pin connector for about 
> $16.50 total price. I have them on 3 motorola MTR2000's and they work 
> great.
>
> I don't think I'd personally  want to make a‎ career out of building 
> these but it was fun for a while and I only messed up 3 of them and 
> that was the pin 13 wire connect. Once I started putting hot melt glue 
> on them, I quit breaking off the lead.Jim
>
>
> Sent from my BlackBerry 10 smartphone on the Verizon Wireless 4G LTE 
> network.
> *From: *Larry
> *Sent: *Wednesday, June 24, 2015 20:32
> *To: *ARM Allstar
> *Reply To: *ARM Allstar
> *Subject: *Re: [arm-allstar] A simplified USB FOB modification
>
>
> Pictured in Doug's previous FOB article:
>
> If you are squeamish about connecting to the CM-108 chip there really 
> only needs to be a single wire added directly to the CM-108 chip. That 
> is PTT (pin 13).  COS (pin 48) is accessible on the left side (top or 
> bottom solder joint) of SW1 (Vol DN). If you want/need more room to 
> solder a wire take a needle and press it under each of the 4 corners 
> of SW1 as you touch each corner with a soldering iron. The switch will 
> lift right off and you will have the trace exposed under the left side 
> of the button to make your connection to pin 48.
>
> CTCSS detect (pin 39) is available on the right side of SW2 (Vol UP). 
> The same proceedure will work there if you want that signal.
>
> Larry - N7FM
>
>
> On 06/24/2015 12:28 PM, Doug Crompton wrote:
>
>     Well to answer your two points.  The link on the site for the FOB
>     is not potted. It is the one shown in the photos. As far as
>     soldering is concerned there are only two potentially tricky
>     connections to the pins of the CM108 but as I pointed out if you
>     use the right size wire and tack it on it is not a big deal. You
>     might be surprised how easy it is. At $3 each sacrifice one to
>     experiment and maybe it won't even be a sacrifice! The rest of the
>     components you can mount or build anyway you desire. It is shown
>     in a DB25 shell but that is certainly not a requirement. At first
>     I was going to put a little perf board in there but then realized
>     that most of the components could be mounted right of the connector.
>
>     *73 Doug
>     WA3DSP
>     http://www.crompton.com/hamradio*
>
>
>     ------------------------------------------------------------------------
>     Date: Wed, 24 Jun 2015 11:44:16 -0600
>     From: mike at mtweb.net <mailto:mike at mtweb.net>
>     To: arm-allstar at hamvoip.org <mailto:arm-allstar at hamvoip.org>
>     Subject: Re: [arm-allstar] A simplified USB FOB modification
>
>     On 6/24/2015 3:42 AM, Corey Dean wrote:
>
>         One of the Main reasons I was looking for this in acid and now
>         the pi2 is due to the blob.  Some of us ordered a bunch just
>         to find you could't get to the chip to modify it.
>
>         Corey N3FE
>
>         On Jun 24, 2015, at 2:11 AM, Doug Crompton <doug at crompton.com
>         <mailto:doug at crompton.com>> wrote:
>
>             I often get requests for GPIO control of COS and PTT on
>             the BBB and RPi2. While we are going to have that
>             capability in the next release at least for the RPi2 I
>             often wonder why the great desire to do this and what the
>             problem is with just modifying the FOB. No matter where
>             the I/O control comes from you still have to build a
>             minimal interface for the signals. Having it all come from
>             one place, the FOB, has several advantages. One is you can
>             use the code as it is now, the other is is you are not
>             tying up I/O on the main board and running wires from two
>             different places.
>
>             In our testing I have built and tested it both ways GPIO 
>             from the RPi2 or the FOB and I honestly think it is easier
>             to just modify the FOB. I have written an article showing
>             an easy way to modify the FOB that I think most hams who
>             have soldering and small construction experience could
>             handle. It saves you about $70/node to do this and a
>             couple of hours of your time. The article is in the how-to
>             section at hamvoip.org <http://hamvoip.org>
>
>             Here is a direct link to it -
>
>             http://crompton.com/hamradio/usb_fob_simple_modification/
>
>             So give it a try. You certainly don't have much to lose at
>             about $3.50 in single quantities!
>
>             I would be glad to answer any questions you may have about
>             this project.
>
>             *73 Doug
>             WA3DSP
>             http://www.crompton.com/hamradio*
>
>             _______________________________________________
>
>             arm-allstar mailing list
>             arm-allstar at hamvoip.org <mailto:arm-allstar at hamvoip.org>
>             http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
>
>             Visit the BBB web page -
>             http://www.crompton.com/hamradio/BeagleBoneBlackAllstar/
>
>
>
>         _______________________________________________
>
>         arm-allstar mailing list
>         arm-allstar at hamvoip.org  <mailto:arm-allstar at hamvoip.org>
>         http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
>
>         Visit the BBB web page -http://www.crompton.com/hamradio/BeagleBoneBlackAllstar/
>
>     For me, it is my eye site, isn't as good as it use to be and
>     everything has gotten way to small.
>     Just finished up building a controller and had to use a 5x
>     magnifier.  At least when you bread board stuff you can space
>     things 2 microns further apart than half an atom:)
>     I think most hams are older now.  I don't see the younger crowd
>     getting in to the hobby, sad to say.  So size of stuff is more
>     important to me now.  As I wont tackle a project that requires a
>     lot of smt components.
>     Mike
>
>     _______________________________________________ arm-allstar
>     mailing list arm-allstar at hamvoip.org
>     <mailto:arm-allstar at hamvoip.org>
>     http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
>     Visit the BBB web page -
>     http://www.crompton.com/hamradio/BeagleBoneBlackAllstar/
>
>
>     _______________________________________________
>
>     arm-allstar mailing list
>     arm-allstar at hamvoip.org  <mailto:arm-allstar at hamvoip.org>
>     http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
>
>     Visit the BBB web page -http://www.crompton.com/hamradio/BeagleBoneBlackAllstar/
>
>
>
>
> _______________________________________________ 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
>
>
> _______________________________________________
>
> 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/20150625/fed08d11/attachment-0001.html>


More information about the arm-allstar mailing list