[arm-allstar] Analog inputs on BBB

[Elliott L]

Hi Doug and All,

Do you know where I can find the kernel source that was used
for 3.16.3-1-ARCH? This is needed before the device tree can be rebuilt
(the github code you uncovered -- very applicable -- does not cover
releases prior to 3.19.x). I can't find the headers or source anywhere for
this arch-specific kernel build. My knowledge of arch linux and the whole
rolling-release scheme is very limited, so any input would be great. I
would guess you ran into this compiling the DAHDI against the current
kernel?

Thanks again,

--E

On Mon, Jan 2, 2017 at 10:16 PM, Elliott L <kilocharlie8 at gmail.com> wrote:

> Hi Doug,
>
> Thank you for your quick reply!
>
> I am going to try what is suggested in that link -- it sounds exactly
> right. I will try the reboot after I make another backup.
>
> With regards to the input level, this particular circuit cannot create
> more than about 0.770 volts, so I think there is a reasonable expectation
> of not exceeding the headroom. But I'll pick up a zener if I see one.
>
> The USB solution is probably better since it would work on any computer,
> in particular a RPi, which will be an upgrade I make in the near future.
>
> Thanks again for your continued support on Allstar,
>
> --E
>
> On Mon, Jan 2, 2017 at 7:42 PM, "Doug Crompton via arm-allstar" <
> arm-allstar at hamvoip.org> wrote:
>
>> Elliott,
>>
>>  First of you may already know this but let me warn you that the ADC pins
>> are max 1.8 volts on the BBB. So you need to scale anything down and make
>> sure it does not exceed that. A zener and series resistor would be a good
>> idea for protection.
>>
>> The later kernels abandoned or changed the cape manager. I don't remember
>> exactly at what point that happened but Dave would know. Here is a link to
>> some info that might help. If you do need to upgrade and recompile you
>> could experiment on an SD card copy of what you have so you can go back.
>>
>> https://gist.github.com/matthewmcneely/bf44655c74096ff96475
>>
>> As a side not the Arduino boards (nano) have ADC inputs and could be used
>> to read analog voltages. This would be done via USB and would be
>> independent of the processor board. This might be a better approach should
>> the BBB method not work out. The BBB is becoming an unsupported board  and
>> it is not clear how long there will be updates for it.
>>
>>
>>
>> *73 Doug*
>>
>> *WA3DSP*
>>
>> *http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*
>>
>> On Mon, Jan 2, 2017 at 8:31 PM, "Elliott L via arm-allstar" <
>> arm-allstar at hamvoip.org> wrote:
>>
>> > Hi All,
>> >
>> > Does anyone know how to access the analog inputs on the beagle bone
>> black
>> > using the Ham VoIP release with kernel 3.16? I do not see any of the
>> usual
>> > entries in /sys for the analog pins. I do see something for the GPIO
>> pins
>> > in /sys/class/gpio/ which looks functional, but not analog.
>> >
>> > I have wired the first analog input pin of the BBB's header to the IF
>> > amplifier in my GE MSTR Exec II receiver, and I am hoping to be able to
>> > report signal levels over the air by reading out the voltage. I remember
>> > some repeaters having this capability "back in the day" using expensive
>> > computerized controllers. Should be a piece of cake with a real computer
>> > available.
>> >
>> > I know these ADCs are pretty low quality but I think for low-precision
>> DC
>> > measurements they should be sufficient.
>> >
>> > Any help before I start upgrading packages and breaking stuff would be
>> > greatly appreciated ;-) Once I get the script working I will share it
>> here.
>> >
>> > Happy New Year all,
>> >
>> > --Elliott, W6EL
>> > _______________________________________________
>> >
>> > arm-allstar mailing list
>> > arm-allstar at hamvoip.org
>> > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
>> >
>> > Visit the BBB and RPi2/3 web page - http://hamvoip.org
>> >
>> >
>> _______________________________________________
>>
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>>
>> Visit the BBB and RPi2/3 web page - http://hamvoip.org
>>
>
>