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12V trigger

epsilon24

Re: 12V trigger

Postby mpa2 » December 22nd, 2017, 10:06 am

Added an OR (XOR) gate at the output, and the cap's. It's still working :) Have to struggle with some design rules though.

12V-Trigger_2.png


PCB_LQ.png
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Re: 12V trigger

Postby mpa2 » January 17th, 2018, 1:41 pm

Had to modify the schematic a little, and here we go:

12V Trigger 0.6.jpg


The SMD version also seems to do what it supposed to. Time to test it with ε24 in real life.

The ε24 itself however makes some troubles. During long test runs it switches off sporadically. I've already read about this problem here. Interestingly, switching on an AV receiver (huge transformer, very high inrush current, sometimes causing a 16A "C" circuit breaker to disengage), connected to the same socket doesn't have any effect on ε24, so it is probably not a mains voltage drop that leads to this behavior. How did you guys cure your ε24's?
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Re: 12V trigger

Postby amb » January 18th, 2018, 3:22 am

Can you correlate the switch-off to any event? Tried the 0.1uF capacitor across the transformer secondary fix? Or increasing the value of C1?
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Re: 12V trigger

Postby mpa2 » January 19th, 2018, 1:05 am

Couldn't see any correlation so far. It switched off once in 1-2 hours, sometimes it worked much longer. Anyway, I increased the C1 to 1000uf and added 100nf at AC in, maybe it will cure it. I could imagine that the problem is on the "switch" side, maybe RF, though. The switch seems to be very sensitive, maybe some additional capacitance there could be the way to go.

Another thing is, for the trigger circuit logic I need 12V as an amplifier "on" state signal. I assumed, I could pick it at ε24, but of course I was wrong :) Would be easy to modify logic to use "low" as on state, but the device is ready... So a workaround was necessary.
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Re: 12V trigger

Postby mpa2 » January 20th, 2018, 8:03 am

So, the trigger circuit is built in an works fine, now i don't have to move my ass to switch Beta24 on :)

Another point is, I could indeed find out what causes the ε24 to unlatch. I couldn't believe it first, but switching light in a restroom on causes Beta24 to switch off. It happens in 9 of 10 cases. The restroom is about 10 m away, three walls between, it has its own circuit and a circuit breaker (could be on the same phase with the living room though), and it is only a small LED PSU and two 2 Watts LED lights, nothing more...

I know that LED SMPS's are noisy, I even switch off my LED workbench light when working with an oscilloscope, but i couldn't imagine that such small unit could interact with an ε24 so far away and in a different circuit.

Any idea how could i solve this problem? C1 is increased to 1000 uF and 0.1uF on AC input is installed. Changing the LED supply is of course an option, but maybe there are another possibilities :)
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12V trigger

Postby amb » January 20th, 2018, 8:34 am

Wow. Maybe the switch is arcing on the LED light? Try installing a 0.1uF capacitor across the LED light’s switch contacts if it’s possible. The capacitor voltage rating must be high enough for the purpose of course.
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Re: 12V trigger

Postby mpa2 » January 20th, 2018, 10:30 am

I would expect arcing, if any, when switching off, but the load is negligible. Maybe I can catch HF spikes with the oscilloscope, but the question will still be how to get rid of them or let them stay outside the Beta...
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Re: 12V trigger

Postby amb » January 20th, 2018, 11:37 am

You've tried the usual measures, and they seem to be insufficient. Even though the culprit is a lowly LED light, we don't know what the magnitude of the glitch is, and there is no sure way to cure all such glitches unless you're running on a good power conditioner...
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Re: 12V trigger

Postby mpa2 » January 21st, 2018, 7:06 am

I have installed a different LED power supply an added ferrite beads on its input and output wires. The problem seems to be solved.

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Re: 12V trigger

Postby amb » January 21st, 2018, 1:25 pm

Great!
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