[ARC5] adventures in battery ops

Tue Apr 7 09:17:13 EDT 2015

I have a question about the original premise of this thread.You mentioned  that you are using the radios in mobile mode, so why not operate them on the car battery?
There is a very non-destructive method for putting all the filaments in parallel which is just a matter of moving a few connections.At present, I am using a 12 volt dynamotor, but I am going to  build a replacement 12v SMPS supply to fit onto the dynamotor plug.I found that the noise in these radios is dramatically reduced if the receiver rack is grounded to the frame of the vehicle with a short strap. The noise is probably dynamotor hash, so I am curious how much less noise and current demand will come from a properly bypassed SMPS.

     On Monday, April 6, 2015 7:21 PM, AKLDGUY . <neilb0627 at gmail.com> wrote:

 Hi Bill

OK, I see you have other reasons for using the Arduino. I have not listened
on HF for many years, but the work I'm doing on getting my BC-230 up and
running will soon change that.

Yes, the op-amp comparator will be ideal for field use, consuming only a
few mA.

All the best in the learning curve with the Arduino, something I haven't
tackled yet.

73 de Neil ZL1ANM

Sent from my Raspberry Pi computer, running Debian 7.8 (Linux optimized for
the Pi).

On Tue, Apr 7, 2015 at 1:06 AM, Bill Cromwell <wrcromwell at gmail.com> wrote:

> Hi Neil,
>
> The Arduino, or any computer at all really *is* overkill for this
> particular job. That is the first thing that occurred to me. Next thing
> that occurred to me about a half second later is having to deal with the
> digital noise it might add. Have you listened to LF and low MF lately.
> What's a little more noise <evil grin>. It might not be too difficult to
> suppress.
>
> The real reason to use the Arduino is to gain more experience using it.
> The next step will be using the computers to monitor and help control
> battery charges - with data logging. The data logging part will help track
> battery health. I'm still doing that with paper and as I get more batteries
> it consumes more time. I also want to use the data logging in other, non
> radio investigations. It's time to trade in the clipboard. So this is
> really a stepping stone to bigger projects. And..I get to point at the cool
> Arduino and the pretty blinking LEDs.
>
> I am NOT going to drag all that to the park with me for field operations!!
> An op-amp comparator with an LED will do nicely. That is even smaller than
> a dedicated voltmeter. Umm...how much are they getting for those Harbor
> Freight DMMs?
>
> 73,
>
> Bill  KU8H
>
>
> On 04/06/2015 02:54 AM, AKLDGUY . wrote:
>
>> Arduino seems a bit overkill for battery level warning.
>> Why not configure a $2 op-amp in a window comparator circuit?
>>
>> I set one up years ago to monitor the falling voltage of my cellphone's
>> NiCad battery, when discharging in my homebrew discharger
>> (remember how we had to ensure NiCads were fully discharged before
>> charging?). The window comparator's output operated a high-pitched
>> buzzer via a cheap transistor of the BC108 class.
>>
>> For those who don't know, a window comparator makes use of the
>> way the op-amp's output rapidly switches from ground to + rail (or vice
>> versa) when one of its input voltages crosses the threshhold voltage on
>> the other input.
>>
>> With a voltage divider or pot, you set the desired battery minimum
>> voltage (eg. 11.5 volts) on the appropriate input of the op-amp and
>> connect the battery to the other input. Nothing happens 'till the battery
>> discharges to the preset voltage, when the op-amp abruptly turns on
>> (or off), triggering the buzzer.
>>
>> 73 de Neil ZL1ANM
>>
>>
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