[GreenKeys] Auto Machine Power Switch

[Harold Hallikainen]

Attached is a circuit and simulation. So far, I have not built it, just
simulated it using LTSPICE.

The entire circuit can be floating, anywhere in the loop. R2 senses the 60
mA current and develops about 6.3 volts when there is 60 mA. The stuff to
the left of R2 is just simulating the loop. D3 and C3 provide the high
side voltage of about 5.6 volts to the SSR control input (R4).

When idle (with loop current), C1 charges through D1 to about 5.6 volts
with the positive side on the left. This puts 0.7 volts on the left side
of D2, so no current flows through D2 or the base of Q1.

When the loop current is interrupted (by a start bit), the voltage across
R2 drops to zero, and C1 is discharged. When the loop current returns,
there is now 0V across C1, so the 6.3 volts on the high side of R2 is
passed through D2, charging C2, and turning on Q1. This pulls the low side
of the SSR control input low, turning on the motor.

In the waveform graph, the green trace is the voltage at the top of R2.
The red trace is the collector voltage of Q1. You can see that on the
first loop current interruption, Q1 collector voltage drops to about a
volt, turning on the SSR. On the next loop current interruption, Q1
collector voltage drops to the saturation voltage of Q1 (about 300 mV). It
stays there until about a minute after the last loop current interruption.

I am thinking about putting this in a "patch panel" that has a loop
supply, a bunch of 1/4 inch TRS jacks, and an AC outlet for the motor.

Harold
https://w6iwi.org


On Fri, December 8, 2023 7:02 am, Daniel Jones wrote:
>
> I use a TU-170 for my machines for autostart which is convenient 
because it automatically powers up the machine upon receiving a signal.
I would like to build something that would allow me to do the same for
850 shift that would allow me to leave my machines on while using my
military gear.
>
> I guess it could be audio driven or even loop driven (once it detects
loop activity it turns the motor on) I would prefer a loop driven option
as it would eliminate the need to differentiate between 170/850.   I
could install it close to the machine if it was in a different room on
an extended loop run ect…
>
> Does anyone have any ideas on a good workable solution?
>
> Daniel
>
>
>
> www.K6YIC.com
> DJones at K6YIC.com
> HH#11973
> ______________________________________________________________
> GreenKeys mailing list
> Home: http://mailman.qth.net/mailman/listinfo/greenkeys
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:GreenKeys at mailman.qth.net
>
>>>> Jordan Spencer Cunningham's GreenKeys Search Tool:
>>>> https://teletype.net/gksearch
>>>> 2002-to-present greenkeys archive:
>>>> http://mailman.qth.net/pipermail/greenkeys/
>>>> 1998-to-2001 greenkeys archive:
>>>> http://mailman.qth.net/archive/greenkeys/greenkeys.html
>>>> Randy Guttery's 2001-to-2009 GreenKeys Search Tool:
>>>> http://comcents.com/tty/greenkeyssearch.html
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
Message delivered to harold at w6iwi.org
>


-- 
Not sent from an iPhone.


-- 
Not sent from an iPhone.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: AutostartSchematic.png
Type: image/png
Size: 22756 bytes
Desc: not available
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20231208/5d83d32d/attachment.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: AutostartWaveform.png
Type: image/png
Size: 25224 bytes
Desc: not available
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20231208/5d83d32d/attachment-0001.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Autostart.asc
Type: application/octet-stream
Size: 1675 bytes
Desc: not available
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20231208/5d83d32d/attachment.obj>